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3839 lines
158 KiB
Rust
3839 lines
158 KiB
Rust
// ignore-tidy-filelength
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use super::diagnostics::SnapshotParser;
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use super::pat::{CommaRecoveryMode, Expected, RecoverColon, RecoverComma};
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use super::ty::{AllowPlus, RecoverQPath, RecoverReturnSign};
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use super::{
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AttrWrapper, BlockMode, ClosureSpans, ForceCollect, Parser, PathStyle, Restrictions,
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SemiColonMode, SeqSep, TokenExpectType, TokenType, TrailingToken,
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};
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use crate::errors;
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use crate::maybe_recover_from_interpolated_ty_qpath;
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use ast::mut_visit::{noop_visit_expr, MutVisitor};
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use ast::{CoroutineKind, ForLoopKind, GenBlockKind, Pat, Path, PathSegment};
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use core::mem;
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use rustc_ast::ptr::P;
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use rustc_ast::token::{self, Delimiter, Token, TokenKind};
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use rustc_ast::tokenstream::Spacing;
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use rustc_ast::util::case::Case;
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use rustc_ast::util::classify;
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use rustc_ast::util::parser::{prec_let_scrutinee_needs_par, AssocOp, Fixity};
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use rustc_ast::visit::Visitor;
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use rustc_ast::{self as ast, AttrStyle, AttrVec, CaptureBy, ExprField, UnOp, DUMMY_NODE_ID};
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use rustc_ast::{AnonConst, BinOp, BinOpKind, FnDecl, FnRetTy, MacCall, Param, Ty, TyKind};
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use rustc_ast::{Arm, BlockCheckMode, Expr, ExprKind, Label, Movability, RangeLimits};
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use rustc_ast::{ClosureBinder, MetaItemLit, StmtKind};
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use rustc_ast_pretty::pprust;
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use rustc_data_structures::stack::ensure_sufficient_stack;
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use rustc_errors::{
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AddToDiagnostic, Applicability, Diagnostic, DiagnosticBuilder, PResult, StashKey,
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};
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use rustc_macros::Subdiagnostic;
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use rustc_session::errors::{report_lit_error, ExprParenthesesNeeded};
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use rustc_session::lint::builtin::BREAK_WITH_LABEL_AND_LOOP;
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use rustc_session::lint::BuiltinLintDiagnostics;
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use rustc_span::source_map::{self, Spanned};
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use rustc_span::symbol::kw::PathRoot;
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use rustc_span::symbol::{kw, sym, Ident, Symbol};
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use rustc_span::{BytePos, Pos, Span};
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use thin_vec::{thin_vec, ThinVec};
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/// Possibly accepts an `token::Interpolated` expression (a pre-parsed expression
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/// dropped into the token stream, which happens while parsing the result of
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/// macro expansion). Placement of these is not as complex as I feared it would
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/// be. The important thing is to make sure that lookahead doesn't balk at
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/// `token::Interpolated` tokens.
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macro_rules! maybe_whole_expr {
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($p:expr) => {
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if let token::Interpolated(nt) = &$p.token.kind {
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match &nt.0 {
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token::NtExpr(e) | token::NtLiteral(e) => {
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let e = e.clone();
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$p.bump();
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return Ok(e);
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}
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token::NtPath(path) => {
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let path = (**path).clone();
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$p.bump();
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return Ok($p.mk_expr($p.prev_token.span, ExprKind::Path(None, path)));
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}
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token::NtBlock(block) => {
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let block = block.clone();
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$p.bump();
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return Ok($p.mk_expr($p.prev_token.span, ExprKind::Block(block, None)));
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}
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_ => {}
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};
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}
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};
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}
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#[derive(Debug)]
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pub(super) enum LhsExpr {
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NotYetParsed,
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AttributesParsed(AttrWrapper),
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AlreadyParsed { expr: P<Expr>, starts_statement: bool },
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}
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impl From<Option<AttrWrapper>> for LhsExpr {
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/// Converts `Some(attrs)` into `LhsExpr::AttributesParsed(attrs)`
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/// and `None` into `LhsExpr::NotYetParsed`.
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///
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/// This conversion does not allocate.
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fn from(o: Option<AttrWrapper>) -> Self {
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if let Some(attrs) = o { LhsExpr::AttributesParsed(attrs) } else { LhsExpr::NotYetParsed }
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}
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}
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impl From<P<Expr>> for LhsExpr {
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/// Converts the `expr: P<Expr>` into `LhsExpr::AlreadyParsed { expr, starts_statement: false }`.
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///
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/// This conversion does not allocate.
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fn from(expr: P<Expr>) -> Self {
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LhsExpr::AlreadyParsed { expr, starts_statement: false }
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}
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}
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#[derive(Debug)]
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enum DestructuredFloat {
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/// 1e2
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Single(Symbol, Span),
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/// 1.
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TrailingDot(Symbol, Span, Span),
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/// 1.2 | 1.2e3
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MiddleDot(Symbol, Span, Span, Symbol, Span),
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/// Invalid
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Error,
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}
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impl<'a> Parser<'a> {
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/// Parses an expression.
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#[inline]
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pub fn parse_expr(&mut self) -> PResult<'a, P<Expr>> {
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self.current_closure.take();
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self.parse_expr_res(Restrictions::empty(), None)
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}
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/// Parses an expression, forcing tokens to be collected
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pub fn parse_expr_force_collect(&mut self) -> PResult<'a, P<Expr>> {
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self.collect_tokens_no_attrs(|this| this.parse_expr())
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}
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pub fn parse_expr_anon_const(&mut self) -> PResult<'a, AnonConst> {
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self.parse_expr().map(|value| AnonConst { id: DUMMY_NODE_ID, value })
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}
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fn parse_expr_catch_underscore(&mut self, restrictions: Restrictions) -> PResult<'a, P<Expr>> {
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match self.parse_expr_res(restrictions, None) {
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Ok(expr) => Ok(expr),
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Err(mut err) => match self.token.ident() {
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Some((Ident { name: kw::Underscore, .. }, false))
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if self.may_recover() && self.look_ahead(1, |t| t == &token::Comma) =>
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{
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// Special-case handling of `foo(_, _, _)`
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err.emit();
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self.bump();
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Ok(self.mk_expr(self.prev_token.span, ExprKind::Err))
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}
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_ => Err(err),
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},
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}
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}
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/// Parses a sequence of expressions delimited by parentheses.
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fn parse_expr_paren_seq(&mut self) -> PResult<'a, ThinVec<P<Expr>>> {
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self.parse_paren_comma_seq(|p| p.parse_expr_catch_underscore(Restrictions::empty()))
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.map(|(r, _)| r)
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}
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/// Parses an expression, subject to the given restrictions.
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#[inline]
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pub(super) fn parse_expr_res(
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&mut self,
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r: Restrictions,
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already_parsed_attrs: Option<AttrWrapper>,
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) -> PResult<'a, P<Expr>> {
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self.with_res(r, |this| this.parse_expr_assoc(already_parsed_attrs))
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}
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/// Parses an associative expression.
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///
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/// This parses an expression accounting for associativity and precedence of the operators in
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/// the expression.
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#[inline]
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fn parse_expr_assoc(
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&mut self,
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already_parsed_attrs: Option<AttrWrapper>,
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) -> PResult<'a, P<Expr>> {
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self.parse_expr_assoc_with(0, already_parsed_attrs.into())
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}
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/// Parses an associative expression with operators of at least `min_prec` precedence.
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pub(super) fn parse_expr_assoc_with(
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&mut self,
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min_prec: usize,
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lhs: LhsExpr,
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) -> PResult<'a, P<Expr>> {
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let mut starts_stmt = false;
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let mut lhs = if let LhsExpr::AlreadyParsed { expr, starts_statement } = lhs {
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starts_stmt = starts_statement;
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expr
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} else {
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let attrs = match lhs {
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LhsExpr::AttributesParsed(attrs) => Some(attrs),
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_ => None,
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};
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if self.token.is_range_separator() {
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return self.parse_expr_prefix_range(attrs);
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} else {
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self.parse_expr_prefix(attrs)?
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}
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};
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if !self.should_continue_as_assoc_expr(&lhs) {
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return Ok(lhs);
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}
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self.expected_tokens.push(TokenType::Operator);
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while let Some(op) = self.check_assoc_op() {
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let lhs_span = self.interpolated_or_expr_span(&lhs);
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let cur_op_span = self.token.span;
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let restrictions = if op.node.is_assign_like() {
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self.restrictions & Restrictions::NO_STRUCT_LITERAL
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} else {
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self.restrictions
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};
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let prec = op.node.precedence();
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if prec < min_prec {
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break;
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}
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// Check for deprecated `...` syntax
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if self.token == token::DotDotDot && op.node == AssocOp::DotDotEq {
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self.err_dotdotdot_syntax(self.token.span);
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}
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if self.token == token::LArrow {
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self.err_larrow_operator(self.token.span);
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}
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self.bump();
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if op.node.is_comparison() {
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if let Some(expr) = self.check_no_chained_comparison(&lhs, &op)? {
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return Ok(expr);
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}
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}
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// Look for JS' `===` and `!==` and recover
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if (op.node == AssocOp::Equal || op.node == AssocOp::NotEqual)
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&& self.token.kind == token::Eq
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&& self.prev_token.span.hi() == self.token.span.lo()
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{
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let sp = op.span.to(self.token.span);
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let sugg = match op.node {
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AssocOp::Equal => "==",
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AssocOp::NotEqual => "!=",
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_ => unreachable!(),
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}
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.into();
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let invalid = format!("{sugg}=");
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self.sess.emit_err(errors::InvalidComparisonOperator {
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span: sp,
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invalid: invalid.clone(),
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sub: errors::InvalidComparisonOperatorSub::Correctable {
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span: sp,
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invalid,
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correct: sugg,
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},
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});
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self.bump();
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}
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// Look for PHP's `<>` and recover
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if op.node == AssocOp::Less
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&& self.token.kind == token::Gt
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&& self.prev_token.span.hi() == self.token.span.lo()
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{
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let sp = op.span.to(self.token.span);
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self.sess.emit_err(errors::InvalidComparisonOperator {
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span: sp,
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invalid: "<>".into(),
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sub: errors::InvalidComparisonOperatorSub::Correctable {
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span: sp,
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invalid: "<>".into(),
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correct: "!=".into(),
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},
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});
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self.bump();
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}
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// Look for C++'s `<=>` and recover
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if op.node == AssocOp::LessEqual
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&& self.token.kind == token::Gt
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&& self.prev_token.span.hi() == self.token.span.lo()
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{
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let sp = op.span.to(self.token.span);
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self.sess.emit_err(errors::InvalidComparisonOperator {
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span: sp,
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invalid: "<=>".into(),
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sub: errors::InvalidComparisonOperatorSub::Spaceship(sp),
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});
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self.bump();
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}
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if self.prev_token == token::BinOp(token::Plus)
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&& self.token == token::BinOp(token::Plus)
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&& self.prev_token.span.between(self.token.span).is_empty()
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{
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let op_span = self.prev_token.span.to(self.token.span);
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// Eat the second `+`
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self.bump();
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lhs = self.recover_from_postfix_increment(lhs, op_span, starts_stmt)?;
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continue;
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}
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if self.prev_token == token::BinOp(token::Minus)
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&& self.token == token::BinOp(token::Minus)
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&& self.prev_token.span.between(self.token.span).is_empty()
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&& !self.look_ahead(1, |tok| tok.can_begin_expr())
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{
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let op_span = self.prev_token.span.to(self.token.span);
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// Eat the second `-`
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self.bump();
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lhs = self.recover_from_postfix_decrement(lhs, op_span, starts_stmt)?;
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continue;
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}
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let op = op.node;
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// Special cases:
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if op == AssocOp::As {
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lhs = self.parse_assoc_op_cast(lhs, lhs_span, ExprKind::Cast)?;
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continue;
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} else if op == AssocOp::DotDot || op == AssocOp::DotDotEq {
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// If we didn't have to handle `x..`/`x..=`, it would be pretty easy to
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// generalise it to the Fixity::None code.
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lhs = self.parse_expr_range(prec, lhs, op, cur_op_span)?;
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break;
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}
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let fixity = op.fixity();
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let prec_adjustment = match fixity {
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Fixity::Right => 0,
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Fixity::Left => 1,
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// We currently have no non-associative operators that are not handled above by
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// the special cases. The code is here only for future convenience.
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Fixity::None => 1,
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};
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let rhs = self.with_res(restrictions - Restrictions::STMT_EXPR, |this| {
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this.parse_expr_assoc_with(prec + prec_adjustment, LhsExpr::NotYetParsed)
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})?;
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let span = self.mk_expr_sp(&lhs, lhs_span, rhs.span);
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lhs = match op {
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AssocOp::Add
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| AssocOp::Subtract
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| AssocOp::Multiply
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| AssocOp::Divide
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| AssocOp::Modulus
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| AssocOp::LAnd
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| AssocOp::LOr
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| AssocOp::BitXor
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| AssocOp::BitAnd
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| AssocOp::BitOr
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| AssocOp::ShiftLeft
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| AssocOp::ShiftRight
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| AssocOp::Equal
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| AssocOp::Less
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| AssocOp::LessEqual
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| AssocOp::NotEqual
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| AssocOp::Greater
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| AssocOp::GreaterEqual => {
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let ast_op = op.to_ast_binop().unwrap();
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let binary = self.mk_binary(source_map::respan(cur_op_span, ast_op), lhs, rhs);
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self.mk_expr(span, binary)
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}
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AssocOp::Assign => self.mk_expr(span, ExprKind::Assign(lhs, rhs, cur_op_span)),
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AssocOp::AssignOp(k) => {
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let aop = match k {
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token::Plus => BinOpKind::Add,
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token::Minus => BinOpKind::Sub,
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token::Star => BinOpKind::Mul,
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token::Slash => BinOpKind::Div,
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token::Percent => BinOpKind::Rem,
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token::Caret => BinOpKind::BitXor,
|
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token::And => BinOpKind::BitAnd,
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token::Or => BinOpKind::BitOr,
|
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token::Shl => BinOpKind::Shl,
|
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token::Shr => BinOpKind::Shr,
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};
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let aopexpr = self.mk_assign_op(source_map::respan(cur_op_span, aop), lhs, rhs);
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self.mk_expr(span, aopexpr)
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}
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AssocOp::As | AssocOp::DotDot | AssocOp::DotDotEq => {
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self.dcx().span_bug(span, "AssocOp should have been handled by special case")
|
|
}
|
|
};
|
|
|
|
if let Fixity::None = fixity {
|
|
break;
|
|
}
|
|
}
|
|
|
|
Ok(lhs)
|
|
}
|
|
|
|
fn should_continue_as_assoc_expr(&mut self, lhs: &Expr) -> bool {
|
|
match (self.expr_is_complete(lhs), AssocOp::from_token(&self.token)) {
|
|
// Semi-statement forms are odd:
|
|
// See https://github.com/rust-lang/rust/issues/29071
|
|
(true, None) => false,
|
|
(false, _) => true, // Continue parsing the expression.
|
|
// An exhaustive check is done in the following block, but these are checked first
|
|
// because they *are* ambiguous but also reasonable looking incorrect syntax, so we
|
|
// want to keep their span info to improve diagnostics in these cases in a later stage.
|
|
(true, Some(AssocOp::Multiply)) | // `{ 42 } *foo = bar;` or `{ 42 } * 3`
|
|
(true, Some(AssocOp::Subtract)) | // `{ 42 } -5`
|
|
(true, Some(AssocOp::Add)) | // `{ 42 } + 42` (unary plus)
|
|
(true, Some(AssocOp::LAnd)) | // `{ 42 } &&x` (#61475) or `{ 42 } && if x { 1 } else { 0 }`
|
|
(true, Some(AssocOp::LOr)) | // `{ 42 } || 42` ("logical or" or closure)
|
|
(true, Some(AssocOp::BitOr)) // `{ 42 } | 42` or `{ 42 } |x| 42`
|
|
=> {
|
|
// These cases are ambiguous and can't be identified in the parser alone.
|
|
//
|
|
// Bitwise AND is left out because guessing intent is hard. We can make
|
|
// suggestions based on the assumption that double-refs are rarely intentional,
|
|
// and closures are distinct enough that they don't get mixed up with their
|
|
// return value.
|
|
let sp = self.sess.source_map().start_point(self.token.span);
|
|
self.sess.ambiguous_block_expr_parse.borrow_mut().insert(sp, lhs.span);
|
|
false
|
|
}
|
|
(true, Some(op)) if !op.can_continue_expr_unambiguously() => false,
|
|
(true, Some(_)) => {
|
|
self.error_found_expr_would_be_stmt(lhs);
|
|
true
|
|
}
|
|
}
|
|
}
|
|
|
|
/// We've found an expression that would be parsed as a statement,
|
|
/// but the next token implies this should be parsed as an expression.
|
|
/// For example: `if let Some(x) = x { x } else { 0 } / 2`.
|
|
fn error_found_expr_would_be_stmt(&self, lhs: &Expr) {
|
|
self.sess.emit_err(errors::FoundExprWouldBeStmt {
|
|
span: self.token.span,
|
|
token: self.token.clone(),
|
|
suggestion: ExprParenthesesNeeded::surrounding(lhs.span),
|
|
});
|
|
}
|
|
|
|
/// Possibly translate the current token to an associative operator.
|
|
/// The method does not advance the current token.
|
|
///
|
|
/// Also performs recovery for `and` / `or` which are mistaken for `&&` and `||` respectively.
|
|
fn check_assoc_op(&self) -> Option<Spanned<AssocOp>> {
|
|
let (op, span) = match (AssocOp::from_token(&self.token), self.token.ident()) {
|
|
// When parsing const expressions, stop parsing when encountering `>`.
|
|
(
|
|
Some(
|
|
AssocOp::ShiftRight
|
|
| AssocOp::Greater
|
|
| AssocOp::GreaterEqual
|
|
| AssocOp::AssignOp(token::BinOpToken::Shr),
|
|
),
|
|
_,
|
|
) if self.restrictions.contains(Restrictions::CONST_EXPR) => {
|
|
return None;
|
|
}
|
|
(Some(op), _) => (op, self.token.span),
|
|
(None, Some((Ident { name: sym::and, span }, false))) if self.may_recover() => {
|
|
self.sess.emit_err(errors::InvalidLogicalOperator {
|
|
span: self.token.span,
|
|
incorrect: "and".into(),
|
|
sub: errors::InvalidLogicalOperatorSub::Conjunction(self.token.span),
|
|
});
|
|
(AssocOp::LAnd, span)
|
|
}
|
|
(None, Some((Ident { name: sym::or, span }, false))) if self.may_recover() => {
|
|
self.sess.emit_err(errors::InvalidLogicalOperator {
|
|
span: self.token.span,
|
|
incorrect: "or".into(),
|
|
sub: errors::InvalidLogicalOperatorSub::Disjunction(self.token.span),
|
|
});
|
|
(AssocOp::LOr, span)
|
|
}
|
|
_ => return None,
|
|
};
|
|
Some(source_map::respan(span, op))
|
|
}
|
|
|
|
/// Checks if this expression is a successfully parsed statement.
|
|
fn expr_is_complete(&self, e: &Expr) -> bool {
|
|
self.restrictions.contains(Restrictions::STMT_EXPR)
|
|
&& !classify::expr_requires_semi_to_be_stmt(e)
|
|
}
|
|
|
|
/// Parses `x..y`, `x..=y`, and `x..`/`x..=`.
|
|
/// The other two variants are handled in `parse_prefix_range_expr` below.
|
|
fn parse_expr_range(
|
|
&mut self,
|
|
prec: usize,
|
|
lhs: P<Expr>,
|
|
op: AssocOp,
|
|
cur_op_span: Span,
|
|
) -> PResult<'a, P<Expr>> {
|
|
let rhs = if self.is_at_start_of_range_notation_rhs() {
|
|
Some(self.parse_expr_assoc_with(prec + 1, LhsExpr::NotYetParsed)?)
|
|
} else {
|
|
None
|
|
};
|
|
let rhs_span = rhs.as_ref().map_or(cur_op_span, |x| x.span);
|
|
let span = self.mk_expr_sp(&lhs, lhs.span, rhs_span);
|
|
let limits =
|
|
if op == AssocOp::DotDot { RangeLimits::HalfOpen } else { RangeLimits::Closed };
|
|
let range = self.mk_range(Some(lhs), rhs, limits);
|
|
Ok(self.mk_expr(span, range))
|
|
}
|
|
|
|
fn is_at_start_of_range_notation_rhs(&self) -> bool {
|
|
if self.token.can_begin_expr() {
|
|
// Parse `for i in 1.. { }` as infinite loop, not as `for i in (1..{})`.
|
|
if self.token == token::OpenDelim(Delimiter::Brace) {
|
|
return !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL);
|
|
}
|
|
true
|
|
} else {
|
|
false
|
|
}
|
|
}
|
|
|
|
/// Parses prefix-forms of range notation: `..expr`, `..`, `..=expr`.
|
|
fn parse_expr_prefix_range(&mut self, attrs: Option<AttrWrapper>) -> PResult<'a, P<Expr>> {
|
|
// Check for deprecated `...` syntax.
|
|
if self.token == token::DotDotDot {
|
|
self.err_dotdotdot_syntax(self.token.span);
|
|
}
|
|
|
|
debug_assert!(
|
|
self.token.is_range_separator(),
|
|
"parse_prefix_range_expr: token {:?} is not DotDot/DotDotEq",
|
|
self.token
|
|
);
|
|
|
|
let limits = match self.token.kind {
|
|
token::DotDot => RangeLimits::HalfOpen,
|
|
_ => RangeLimits::Closed,
|
|
};
|
|
let op = AssocOp::from_token(&self.token);
|
|
// FIXME: `parse_prefix_range_expr` is called when the current
|
|
// token is `DotDot`, `DotDotDot`, or `DotDotEq`. If we haven't already
|
|
// parsed attributes, then trying to parse them here will always fail.
|
|
// We should figure out how we want attributes on range expressions to work.
|
|
let attrs = self.parse_or_use_outer_attributes(attrs)?;
|
|
self.collect_tokens_for_expr(attrs, |this, attrs| {
|
|
let lo = this.token.span;
|
|
this.bump();
|
|
let (span, opt_end) = if this.is_at_start_of_range_notation_rhs() {
|
|
// RHS must be parsed with more associativity than the dots.
|
|
this.parse_expr_assoc_with(op.unwrap().precedence() + 1, LhsExpr::NotYetParsed)
|
|
.map(|x| (lo.to(x.span), Some(x)))?
|
|
} else {
|
|
(lo, None)
|
|
};
|
|
let range = this.mk_range(None, opt_end, limits);
|
|
Ok(this.mk_expr_with_attrs(span, range, attrs))
|
|
})
|
|
}
|
|
|
|
/// Parses a prefix-unary-operator expr.
|
|
fn parse_expr_prefix(&mut self, attrs: Option<AttrWrapper>) -> PResult<'a, P<Expr>> {
|
|
let attrs = self.parse_or_use_outer_attributes(attrs)?;
|
|
let lo = self.token.span;
|
|
|
|
macro_rules! make_it {
|
|
($this:ident, $attrs:expr, |this, _| $body:expr) => {
|
|
$this.collect_tokens_for_expr($attrs, |$this, attrs| {
|
|
let (hi, ex) = $body?;
|
|
Ok($this.mk_expr_with_attrs(lo.to(hi), ex, attrs))
|
|
})
|
|
};
|
|
}
|
|
|
|
let this = self;
|
|
|
|
// Note: when adding new unary operators, don't forget to adjust TokenKind::can_begin_expr()
|
|
match this.token.uninterpolate().kind {
|
|
// `!expr`
|
|
token::Not => make_it!(this, attrs, |this, _| this.parse_expr_unary(lo, UnOp::Not)),
|
|
// `~expr`
|
|
token::Tilde => make_it!(this, attrs, |this, _| this.recover_tilde_expr(lo)),
|
|
// `-expr`
|
|
token::BinOp(token::Minus) => {
|
|
make_it!(this, attrs, |this, _| this.parse_expr_unary(lo, UnOp::Neg))
|
|
}
|
|
// `*expr`
|
|
token::BinOp(token::Star) => {
|
|
make_it!(this, attrs, |this, _| this.parse_expr_unary(lo, UnOp::Deref))
|
|
}
|
|
// `&expr` and `&&expr`
|
|
token::BinOp(token::And) | token::AndAnd => {
|
|
make_it!(this, attrs, |this, _| this.parse_expr_borrow(lo))
|
|
}
|
|
// `+lit`
|
|
token::BinOp(token::Plus) if this.look_ahead(1, |tok| tok.is_numeric_lit()) => {
|
|
let mut err = errors::LeadingPlusNotSupported {
|
|
span: lo,
|
|
remove_plus: None,
|
|
add_parentheses: None,
|
|
};
|
|
|
|
// a block on the LHS might have been intended to be an expression instead
|
|
if let Some(sp) = this.sess.ambiguous_block_expr_parse.borrow().get(&lo) {
|
|
err.add_parentheses = Some(ExprParenthesesNeeded::surrounding(*sp));
|
|
} else {
|
|
err.remove_plus = Some(lo);
|
|
}
|
|
this.sess.emit_err(err);
|
|
|
|
this.bump();
|
|
this.parse_expr_prefix(None)
|
|
}
|
|
// Recover from `++x`:
|
|
token::BinOp(token::Plus)
|
|
if this.look_ahead(1, |t| *t == token::BinOp(token::Plus)) =>
|
|
{
|
|
let starts_stmt = this.prev_token == token::Semi
|
|
|| this.prev_token == token::CloseDelim(Delimiter::Brace);
|
|
let pre_span = this.token.span.to(this.look_ahead(1, |t| t.span));
|
|
// Eat both `+`s.
|
|
this.bump();
|
|
this.bump();
|
|
|
|
let operand_expr = this.parse_expr_dot_or_call(Default::default())?;
|
|
this.recover_from_prefix_increment(operand_expr, pre_span, starts_stmt)
|
|
}
|
|
token::Ident(..) if this.token.is_keyword(kw::Box) => {
|
|
make_it!(this, attrs, |this, _| this.parse_expr_box(lo))
|
|
}
|
|
token::Ident(..) if this.may_recover() && this.is_mistaken_not_ident_negation() => {
|
|
make_it!(this, attrs, |this, _| this.recover_not_expr(lo))
|
|
}
|
|
_ => return this.parse_expr_dot_or_call(Some(attrs)),
|
|
}
|
|
}
|
|
|
|
fn parse_expr_prefix_common(&mut self, lo: Span) -> PResult<'a, (Span, P<Expr>)> {
|
|
self.bump();
|
|
let expr = self.parse_expr_prefix(None)?;
|
|
let span = self.interpolated_or_expr_span(&expr);
|
|
Ok((lo.to(span), expr))
|
|
}
|
|
|
|
fn parse_expr_unary(&mut self, lo: Span, op: UnOp) -> PResult<'a, (Span, ExprKind)> {
|
|
let (span, expr) = self.parse_expr_prefix_common(lo)?;
|
|
Ok((span, self.mk_unary(op, expr)))
|
|
}
|
|
|
|
/// Recover on `~expr` in favor of `!expr`.
|
|
fn recover_tilde_expr(&mut self, lo: Span) -> PResult<'a, (Span, ExprKind)> {
|
|
self.sess.emit_err(errors::TildeAsUnaryOperator(lo));
|
|
|
|
self.parse_expr_unary(lo, UnOp::Not)
|
|
}
|
|
|
|
/// Parse `box expr` - this syntax has been removed, but we still parse this
|
|
/// for now to provide an automated way to fix usages of it
|
|
fn parse_expr_box(&mut self, lo: Span) -> PResult<'a, (Span, ExprKind)> {
|
|
let (span, expr) = self.parse_expr_prefix_common(lo)?;
|
|
let code = self.sess.source_map().span_to_snippet(span.with_lo(lo.hi())).unwrap();
|
|
self.sess.emit_err(errors::BoxSyntaxRemoved { span, code: code.trim() });
|
|
// So typechecking works, parse `box <expr>` as `::std::boxed::Box::new(expr)`
|
|
let path = Path {
|
|
span,
|
|
segments: [
|
|
PathSegment::from_ident(Ident::with_dummy_span(PathRoot)),
|
|
PathSegment::from_ident(Ident::with_dummy_span(sym::std)),
|
|
PathSegment::from_ident(Ident::from_str("boxed")),
|
|
PathSegment::from_ident(Ident::from_str("Box")),
|
|
PathSegment::from_ident(Ident::with_dummy_span(sym::new)),
|
|
]
|
|
.into(),
|
|
tokens: None,
|
|
};
|
|
let path = self.mk_expr(span, ExprKind::Path(None, path));
|
|
Ok((span, self.mk_call(path, ThinVec::from([expr]))))
|
|
}
|
|
|
|
fn is_mistaken_not_ident_negation(&self) -> bool {
|
|
let token_cannot_continue_expr = |t: &Token| match t.uninterpolate().kind {
|
|
// These tokens can start an expression after `!`, but
|
|
// can't continue an expression after an ident
|
|
token::Ident(name, is_raw) => token::ident_can_begin_expr(name, t.span, is_raw),
|
|
token::Literal(..) | token::Pound => true,
|
|
_ => t.is_whole_expr(),
|
|
};
|
|
self.token.is_ident_named(sym::not) && self.look_ahead(1, token_cannot_continue_expr)
|
|
}
|
|
|
|
/// Recover on `not expr` in favor of `!expr`.
|
|
fn recover_not_expr(&mut self, lo: Span) -> PResult<'a, (Span, ExprKind)> {
|
|
let negated_token = self.look_ahead(1, |t| t.clone());
|
|
|
|
let sub_diag = if negated_token.is_numeric_lit() {
|
|
errors::NotAsNegationOperatorSub::SuggestNotBitwise
|
|
} else if negated_token.is_bool_lit() {
|
|
errors::NotAsNegationOperatorSub::SuggestNotLogical
|
|
} else {
|
|
errors::NotAsNegationOperatorSub::SuggestNotDefault
|
|
};
|
|
|
|
self.sess.emit_err(errors::NotAsNegationOperator {
|
|
negated: negated_token.span,
|
|
negated_desc: super::token_descr(&negated_token),
|
|
// Span the `not` plus trailing whitespace to avoid
|
|
// trailing whitespace after the `!` in our suggestion
|
|
sub: sub_diag(
|
|
self.sess.source_map().span_until_non_whitespace(lo.to(negated_token.span)),
|
|
),
|
|
});
|
|
|
|
self.parse_expr_unary(lo, UnOp::Not)
|
|
}
|
|
|
|
/// Returns the span of expr if it was not interpolated, or the span of the interpolated token.
|
|
fn interpolated_or_expr_span(&self, expr: &Expr) -> Span {
|
|
match self.prev_token.kind {
|
|
TokenKind::Interpolated(..) => self.prev_token.span,
|
|
_ => expr.span,
|
|
}
|
|
}
|
|
|
|
fn parse_assoc_op_cast(
|
|
&mut self,
|
|
lhs: P<Expr>,
|
|
lhs_span: Span,
|
|
expr_kind: fn(P<Expr>, P<Ty>) -> ExprKind,
|
|
) -> PResult<'a, P<Expr>> {
|
|
let mk_expr = |this: &mut Self, lhs: P<Expr>, rhs: P<Ty>| {
|
|
this.mk_expr(this.mk_expr_sp(&lhs, lhs_span, rhs.span), expr_kind(lhs, rhs))
|
|
};
|
|
|
|
// Save the state of the parser before parsing type normally, in case there is a
|
|
// LessThan comparison after this cast.
|
|
let parser_snapshot_before_type = self.clone();
|
|
let cast_expr = match self.parse_as_cast_ty() {
|
|
Ok(rhs) => mk_expr(self, lhs, rhs),
|
|
Err(type_err) => {
|
|
if !self.may_recover() {
|
|
return Err(type_err);
|
|
}
|
|
|
|
// Rewind to before attempting to parse the type with generics, to recover
|
|
// from situations like `x as usize < y` in which we first tried to parse
|
|
// `usize < y` as a type with generic arguments.
|
|
let parser_snapshot_after_type = mem::replace(self, parser_snapshot_before_type);
|
|
|
|
// Check for typo of `'a: loop { break 'a }` with a missing `'`.
|
|
match (&lhs.kind, &self.token.kind) {
|
|
(
|
|
// `foo: `
|
|
ExprKind::Path(None, ast::Path { segments, .. }),
|
|
token::Ident(kw::For | kw::Loop | kw::While, false),
|
|
) if segments.len() == 1 => {
|
|
let snapshot = self.create_snapshot_for_diagnostic();
|
|
let label = Label {
|
|
ident: Ident::from_str_and_span(
|
|
&format!("'{}", segments[0].ident),
|
|
segments[0].ident.span,
|
|
),
|
|
};
|
|
match self.parse_expr_labeled(label, false) {
|
|
Ok(expr) => {
|
|
type_err.cancel();
|
|
self.sess.emit_err(errors::MalformedLoopLabel {
|
|
span: label.ident.span,
|
|
correct_label: label.ident,
|
|
});
|
|
return Ok(expr);
|
|
}
|
|
Err(err) => {
|
|
err.cancel();
|
|
self.restore_snapshot(snapshot);
|
|
}
|
|
}
|
|
}
|
|
_ => {}
|
|
}
|
|
|
|
match self.parse_path(PathStyle::Expr) {
|
|
Ok(path) => {
|
|
let span_after_type = parser_snapshot_after_type.token.span;
|
|
let expr = mk_expr(
|
|
self,
|
|
lhs,
|
|
self.mk_ty(path.span, TyKind::Path(None, path.clone())),
|
|
);
|
|
|
|
let args_span = self.look_ahead(1, |t| t.span).to(span_after_type);
|
|
let suggestion = errors::ComparisonOrShiftInterpretedAsGenericSugg {
|
|
left: expr.span.shrink_to_lo(),
|
|
right: expr.span.shrink_to_hi(),
|
|
};
|
|
|
|
match self.token.kind {
|
|
token::Lt => {
|
|
self.sess.emit_err(errors::ComparisonInterpretedAsGeneric {
|
|
comparison: self.token.span,
|
|
r#type: path,
|
|
args: args_span,
|
|
suggestion,
|
|
})
|
|
}
|
|
token::BinOp(token::Shl) => {
|
|
self.sess.emit_err(errors::ShiftInterpretedAsGeneric {
|
|
shift: self.token.span,
|
|
r#type: path,
|
|
args: args_span,
|
|
suggestion,
|
|
})
|
|
}
|
|
_ => {
|
|
// We can end up here even without `<` being the next token, for
|
|
// example because `parse_ty_no_plus` returns `Err` on keywords,
|
|
// but `parse_path` returns `Ok` on them due to error recovery.
|
|
// Return original error and parser state.
|
|
*self = parser_snapshot_after_type;
|
|
return Err(type_err);
|
|
}
|
|
};
|
|
|
|
// Successfully parsed the type path leaving a `<` yet to parse.
|
|
type_err.cancel();
|
|
|
|
// Keep `x as usize` as an expression in AST and continue parsing.
|
|
expr
|
|
}
|
|
Err(path_err) => {
|
|
// Couldn't parse as a path, return original error and parser state.
|
|
path_err.cancel();
|
|
*self = parser_snapshot_after_type;
|
|
return Err(type_err);
|
|
}
|
|
}
|
|
}
|
|
};
|
|
|
|
self.parse_and_disallow_postfix_after_cast(cast_expr)
|
|
}
|
|
|
|
/// Parses a postfix operators such as `.`, `?`, or index (`[]`) after a cast,
|
|
/// then emits an error and returns the newly parsed tree.
|
|
/// The resulting parse tree for `&x as T[0]` has a precedence of `((&x) as T)[0]`.
|
|
fn parse_and_disallow_postfix_after_cast(
|
|
&mut self,
|
|
cast_expr: P<Expr>,
|
|
) -> PResult<'a, P<Expr>> {
|
|
if let ExprKind::Type(_, _) = cast_expr.kind {
|
|
panic!("ExprKind::Type must not be parsed");
|
|
}
|
|
|
|
let span = cast_expr.span;
|
|
|
|
let with_postfix = self.parse_expr_dot_or_call_with_(cast_expr, span)?;
|
|
|
|
// Check if an illegal postfix operator has been added after the cast.
|
|
// If the resulting expression is not a cast, it is an illegal postfix operator.
|
|
if !matches!(with_postfix.kind, ExprKind::Cast(_, _)) {
|
|
let msg = format!(
|
|
"cast cannot be followed by {}",
|
|
match with_postfix.kind {
|
|
ExprKind::Index(..) => "indexing",
|
|
ExprKind::Try(_) => "`?`",
|
|
ExprKind::Field(_, _) => "a field access",
|
|
ExprKind::MethodCall(_) => "a method call",
|
|
ExprKind::Call(_, _) => "a function call",
|
|
ExprKind::Await(_, _) => "`.await`",
|
|
ExprKind::Err => return Ok(with_postfix),
|
|
_ => unreachable!("parse_dot_or_call_expr_with_ shouldn't produce this"),
|
|
}
|
|
);
|
|
let mut err = self.dcx().struct_span_err(span, msg);
|
|
|
|
let suggest_parens = |err: &mut Diagnostic| {
|
|
let suggestions = vec![
|
|
(span.shrink_to_lo(), "(".to_string()),
|
|
(span.shrink_to_hi(), ")".to_string()),
|
|
];
|
|
err.multipart_suggestion(
|
|
"try surrounding the expression in parentheses",
|
|
suggestions,
|
|
Applicability::MachineApplicable,
|
|
);
|
|
};
|
|
|
|
suggest_parens(&mut err);
|
|
|
|
err.emit();
|
|
};
|
|
Ok(with_postfix)
|
|
}
|
|
|
|
/// Parse `& mut? <expr>` or `& raw [ const | mut ] <expr>`.
|
|
fn parse_expr_borrow(&mut self, lo: Span) -> PResult<'a, (Span, ExprKind)> {
|
|
self.expect_and()?;
|
|
let has_lifetime = self.token.is_lifetime() && self.look_ahead(1, |t| t != &token::Colon);
|
|
let lifetime = has_lifetime.then(|| self.expect_lifetime()); // For recovery, see below.
|
|
let (borrow_kind, mutbl) = self.parse_borrow_modifiers(lo);
|
|
let expr = if self.token.is_range_separator() {
|
|
self.parse_expr_prefix_range(None)
|
|
} else {
|
|
self.parse_expr_prefix(None)
|
|
}?;
|
|
let hi = self.interpolated_or_expr_span(&expr);
|
|
let span = lo.to(hi);
|
|
if let Some(lt) = lifetime {
|
|
self.error_remove_borrow_lifetime(span, lt.ident.span);
|
|
}
|
|
Ok((span, ExprKind::AddrOf(borrow_kind, mutbl, expr)))
|
|
}
|
|
|
|
fn error_remove_borrow_lifetime(&self, span: Span, lt_span: Span) {
|
|
self.sess.emit_err(errors::LifetimeInBorrowExpression { span, lifetime_span: lt_span });
|
|
}
|
|
|
|
/// Parse `mut?` or `raw [ const | mut ]`.
|
|
fn parse_borrow_modifiers(&mut self, lo: Span) -> (ast::BorrowKind, ast::Mutability) {
|
|
if self.check_keyword(kw::Raw) && self.look_ahead(1, Token::is_mutability) {
|
|
// `raw [ const | mut ]`.
|
|
let found_raw = self.eat_keyword(kw::Raw);
|
|
assert!(found_raw);
|
|
let mutability = self.parse_const_or_mut().unwrap();
|
|
self.sess.gated_spans.gate(sym::raw_ref_op, lo.to(self.prev_token.span));
|
|
(ast::BorrowKind::Raw, mutability)
|
|
} else {
|
|
// `mut?`
|
|
(ast::BorrowKind::Ref, self.parse_mutability())
|
|
}
|
|
}
|
|
|
|
/// Parses `a.b` or `a(13)` or `a[4]` or just `a`.
|
|
fn parse_expr_dot_or_call(&mut self, attrs: Option<AttrWrapper>) -> PResult<'a, P<Expr>> {
|
|
let attrs = self.parse_or_use_outer_attributes(attrs)?;
|
|
self.collect_tokens_for_expr(attrs, |this, attrs| {
|
|
let base = this.parse_expr_bottom()?;
|
|
let span = this.interpolated_or_expr_span(&base);
|
|
this.parse_expr_dot_or_call_with(base, span, attrs)
|
|
})
|
|
}
|
|
|
|
pub(super) fn parse_expr_dot_or_call_with(
|
|
&mut self,
|
|
e0: P<Expr>,
|
|
lo: Span,
|
|
mut attrs: ast::AttrVec,
|
|
) -> PResult<'a, P<Expr>> {
|
|
// Stitch the list of outer attributes onto the return value.
|
|
// A little bit ugly, but the best way given the current code
|
|
// structure
|
|
let res = self.parse_expr_dot_or_call_with_(e0, lo);
|
|
if attrs.is_empty() {
|
|
res
|
|
} else {
|
|
res.map(|expr| {
|
|
expr.map(|mut expr| {
|
|
attrs.extend(expr.attrs);
|
|
expr.attrs = attrs;
|
|
expr
|
|
})
|
|
})
|
|
}
|
|
}
|
|
|
|
fn parse_expr_dot_or_call_with_(&mut self, mut e: P<Expr>, lo: Span) -> PResult<'a, P<Expr>> {
|
|
loop {
|
|
let has_question = if self.prev_token.kind == TokenKind::Ident(kw::Return, false) {
|
|
// we are using noexpect here because we don't expect a `?` directly after a `return`
|
|
// which could be suggested otherwise
|
|
self.eat_noexpect(&token::Question)
|
|
} else {
|
|
self.eat(&token::Question)
|
|
};
|
|
if has_question {
|
|
// `expr?`
|
|
e = self.mk_expr(lo.to(self.prev_token.span), ExprKind::Try(e));
|
|
continue;
|
|
}
|
|
let has_dot = if self.prev_token.kind == TokenKind::Ident(kw::Return, false) {
|
|
// we are using noexpect here because we don't expect a `.` directly after a `return`
|
|
// which could be suggested otherwise
|
|
self.eat_noexpect(&token::Dot)
|
|
} else {
|
|
self.eat(&token::Dot)
|
|
};
|
|
if has_dot {
|
|
// expr.f
|
|
e = self.parse_dot_suffix_expr(lo, e)?;
|
|
continue;
|
|
}
|
|
if self.expr_is_complete(&e) {
|
|
return Ok(e);
|
|
}
|
|
e = match self.token.kind {
|
|
token::OpenDelim(Delimiter::Parenthesis) => self.parse_expr_fn_call(lo, e),
|
|
token::OpenDelim(Delimiter::Bracket) => self.parse_expr_index(lo, e)?,
|
|
_ => return Ok(e),
|
|
}
|
|
}
|
|
}
|
|
|
|
fn parse_dot_suffix_expr(&mut self, lo: Span, base: P<Expr>) -> PResult<'a, P<Expr>> {
|
|
match self.token.uninterpolate().kind {
|
|
token::Ident(..) => self.parse_dot_suffix(base, lo),
|
|
token::Literal(token::Lit { kind: token::Integer, symbol, suffix }) => {
|
|
Ok(self.parse_expr_tuple_field_access(lo, base, symbol, suffix, None))
|
|
}
|
|
token::Literal(token::Lit { kind: token::Float, symbol, suffix }) => {
|
|
Ok(self.parse_expr_tuple_field_access_float(lo, base, symbol, suffix))
|
|
}
|
|
_ => {
|
|
self.error_unexpected_after_dot();
|
|
Ok(base)
|
|
}
|
|
}
|
|
}
|
|
|
|
fn error_unexpected_after_dot(&self) {
|
|
let actual = pprust::token_to_string(&self.token);
|
|
let span = self.token.span;
|
|
let sm = self.sess.source_map();
|
|
let (span, actual) = match (&self.token.kind, self.subparser_name) {
|
|
(token::Eof, Some(_)) if let Ok(actual) = sm.span_to_snippet(sm.next_point(span)) => {
|
|
(span.shrink_to_hi(), actual.into())
|
|
}
|
|
_ => (span, actual),
|
|
};
|
|
self.sess.emit_err(errors::UnexpectedTokenAfterDot { span, actual });
|
|
}
|
|
|
|
// We need an identifier or integer, but the next token is a float.
|
|
// Break the float into components to extract the identifier or integer.
|
|
// FIXME: With current `TokenCursor` it's hard to break tokens into more than 2
|
|
// parts unless those parts are processed immediately. `TokenCursor` should either
|
|
// support pushing "future tokens" (would be also helpful to `break_and_eat`), or
|
|
// we should break everything including floats into more basic proc-macro style
|
|
// tokens in the lexer (probably preferable).
|
|
// See also `TokenKind::break_two_token_op` which does similar splitting of `>>` into `>`.
|
|
fn break_up_float(&mut self, float: Symbol) -> DestructuredFloat {
|
|
#[derive(Debug)]
|
|
enum FloatComponent {
|
|
IdentLike(String),
|
|
Punct(char),
|
|
}
|
|
use FloatComponent::*;
|
|
|
|
let float_str = float.as_str();
|
|
let mut components = Vec::new();
|
|
let mut ident_like = String::new();
|
|
for c in float_str.chars() {
|
|
if c == '_' || c.is_ascii_alphanumeric() {
|
|
ident_like.push(c);
|
|
} else if matches!(c, '.' | '+' | '-') {
|
|
if !ident_like.is_empty() {
|
|
components.push(IdentLike(mem::take(&mut ident_like)));
|
|
}
|
|
components.push(Punct(c));
|
|
} else {
|
|
panic!("unexpected character in a float token: {c:?}")
|
|
}
|
|
}
|
|
if !ident_like.is_empty() {
|
|
components.push(IdentLike(ident_like));
|
|
}
|
|
|
|
// With proc macros the span can refer to anything, the source may be too short,
|
|
// or too long, or non-ASCII. It only makes sense to break our span into components
|
|
// if its underlying text is identical to our float literal.
|
|
let span = self.token.span;
|
|
let can_take_span_apart =
|
|
|| self.span_to_snippet(span).as_deref() == Ok(float_str).as_deref();
|
|
|
|
match &*components {
|
|
// 1e2
|
|
[IdentLike(i)] => {
|
|
DestructuredFloat::Single(Symbol::intern(i), span)
|
|
}
|
|
// 1.
|
|
[IdentLike(i), Punct('.')] => {
|
|
let (ident_span, dot_span) = if can_take_span_apart() {
|
|
let (span, ident_len) = (span.data(), BytePos::from_usize(i.len()));
|
|
let ident_span = span.with_hi(span.lo + ident_len);
|
|
let dot_span = span.with_lo(span.lo + ident_len);
|
|
(ident_span, dot_span)
|
|
} else {
|
|
(span, span)
|
|
};
|
|
let symbol = Symbol::intern(i);
|
|
DestructuredFloat::TrailingDot(symbol, ident_span, dot_span)
|
|
}
|
|
// 1.2 | 1.2e3
|
|
[IdentLike(i1), Punct('.'), IdentLike(i2)] => {
|
|
let (ident1_span, dot_span, ident2_span) = if can_take_span_apart() {
|
|
let (span, ident1_len) = (span.data(), BytePos::from_usize(i1.len()));
|
|
let ident1_span = span.with_hi(span.lo + ident1_len);
|
|
let dot_span = span
|
|
.with_lo(span.lo + ident1_len)
|
|
.with_hi(span.lo + ident1_len + BytePos(1));
|
|
let ident2_span = self.token.span.with_lo(span.lo + ident1_len + BytePos(1));
|
|
(ident1_span, dot_span, ident2_span)
|
|
} else {
|
|
(span, span, span)
|
|
};
|
|
let symbol1 = Symbol::intern(i1);
|
|
let symbol2 = Symbol::intern(i2);
|
|
DestructuredFloat::MiddleDot(symbol1, ident1_span, dot_span, symbol2, ident2_span)
|
|
}
|
|
// 1e+ | 1e- (recovered)
|
|
[IdentLike(_), Punct('+' | '-')] |
|
|
// 1e+2 | 1e-2
|
|
[IdentLike(_), Punct('+' | '-'), IdentLike(_)] |
|
|
// 1.2e+ | 1.2e-
|
|
[IdentLike(_), Punct('.'), IdentLike(_), Punct('+' | '-')] |
|
|
// 1.2e+3 | 1.2e-3
|
|
[IdentLike(_), Punct('.'), IdentLike(_), Punct('+' | '-'), IdentLike(_)] => {
|
|
// See the FIXME about `TokenCursor` above.
|
|
self.error_unexpected_after_dot();
|
|
DestructuredFloat::Error
|
|
}
|
|
_ => panic!("unexpected components in a float token: {components:?}"),
|
|
}
|
|
}
|
|
|
|
fn parse_expr_tuple_field_access_float(
|
|
&mut self,
|
|
lo: Span,
|
|
base: P<Expr>,
|
|
float: Symbol,
|
|
suffix: Option<Symbol>,
|
|
) -> P<Expr> {
|
|
match self.break_up_float(float) {
|
|
// 1e2
|
|
DestructuredFloat::Single(sym, _sp) => {
|
|
self.parse_expr_tuple_field_access(lo, base, sym, suffix, None)
|
|
}
|
|
// 1.
|
|
DestructuredFloat::TrailingDot(sym, ident_span, dot_span) => {
|
|
assert!(suffix.is_none());
|
|
self.token = Token::new(token::Ident(sym, false), ident_span);
|
|
let next_token = (Token::new(token::Dot, dot_span), self.token_spacing);
|
|
self.parse_expr_tuple_field_access(lo, base, sym, None, Some(next_token))
|
|
}
|
|
// 1.2 | 1.2e3
|
|
DestructuredFloat::MiddleDot(symbol1, ident1_span, dot_span, symbol2, ident2_span) => {
|
|
self.token = Token::new(token::Ident(symbol1, false), ident1_span);
|
|
// This needs to be `Spacing::Alone` to prevent regressions.
|
|
// See issue #76399 and PR #76285 for more details
|
|
let next_token1 = (Token::new(token::Dot, dot_span), Spacing::Alone);
|
|
let base1 =
|
|
self.parse_expr_tuple_field_access(lo, base, symbol1, None, Some(next_token1));
|
|
let next_token2 = Token::new(token::Ident(symbol2, false), ident2_span);
|
|
self.bump_with((next_token2, self.token_spacing)); // `.`
|
|
self.parse_expr_tuple_field_access(lo, base1, symbol2, suffix, None)
|
|
}
|
|
DestructuredFloat::Error => base,
|
|
}
|
|
}
|
|
|
|
fn parse_field_name_maybe_tuple(&mut self) -> PResult<'a, ThinVec<Ident>> {
|
|
let token::Literal(token::Lit { kind: token::Float, symbol, suffix }) = self.token.kind
|
|
else {
|
|
return Ok(thin_vec![self.parse_field_name()?]);
|
|
};
|
|
Ok(match self.break_up_float(symbol) {
|
|
// 1e2
|
|
DestructuredFloat::Single(sym, sp) => {
|
|
self.bump();
|
|
thin_vec![Ident::new(sym, sp)]
|
|
}
|
|
// 1.
|
|
DestructuredFloat::TrailingDot(sym, sym_span, dot_span) => {
|
|
assert!(suffix.is_none());
|
|
// Analogous to `Self::break_and_eat`
|
|
self.break_last_token = true;
|
|
// This might work, in cases like `1. 2`, and might not,
|
|
// in cases like `offset_of!(Ty, 1.)`. It depends on what comes
|
|
// after the float-like token, and therefore we have to make
|
|
// the other parts of the parser think that there is a dot literal.
|
|
self.token = Token::new(token::Ident(sym, false), sym_span);
|
|
self.bump_with((Token::new(token::Dot, dot_span), self.token_spacing));
|
|
thin_vec![Ident::new(sym, sym_span)]
|
|
}
|
|
// 1.2 | 1.2e3
|
|
DestructuredFloat::MiddleDot(symbol1, ident1_span, _dot_span, symbol2, ident2_span) => {
|
|
self.bump();
|
|
thin_vec![Ident::new(symbol1, ident1_span), Ident::new(symbol2, ident2_span)]
|
|
}
|
|
DestructuredFloat::Error => {
|
|
self.bump();
|
|
thin_vec![Ident::new(symbol, self.prev_token.span)]
|
|
}
|
|
})
|
|
}
|
|
|
|
fn parse_expr_tuple_field_access(
|
|
&mut self,
|
|
lo: Span,
|
|
base: P<Expr>,
|
|
field: Symbol,
|
|
suffix: Option<Symbol>,
|
|
next_token: Option<(Token, Spacing)>,
|
|
) -> P<Expr> {
|
|
match next_token {
|
|
Some(next_token) => self.bump_with(next_token),
|
|
None => self.bump(),
|
|
}
|
|
let span = self.prev_token.span;
|
|
let field = ExprKind::Field(base, Ident::new(field, span));
|
|
if let Some(suffix) = suffix {
|
|
self.expect_no_tuple_index_suffix(span, suffix);
|
|
}
|
|
self.mk_expr(lo.to(span), field)
|
|
}
|
|
|
|
/// Parse a function call expression, `expr(...)`.
|
|
fn parse_expr_fn_call(&mut self, lo: Span, fun: P<Expr>) -> P<Expr> {
|
|
let snapshot = if self.token.kind == token::OpenDelim(Delimiter::Parenthesis) {
|
|
Some((self.create_snapshot_for_diagnostic(), fun.kind.clone()))
|
|
} else {
|
|
None
|
|
};
|
|
let open_paren = self.token.span;
|
|
|
|
let mut seq = self
|
|
.parse_expr_paren_seq()
|
|
.map(|args| self.mk_expr(lo.to(self.prev_token.span), self.mk_call(fun, args)));
|
|
if let Some(expr) =
|
|
self.maybe_recover_struct_lit_bad_delims(lo, open_paren, &mut seq, snapshot)
|
|
{
|
|
return expr;
|
|
}
|
|
self.recover_seq_parse_error(Delimiter::Parenthesis, lo, seq)
|
|
}
|
|
|
|
/// If we encounter a parser state that looks like the user has written a `struct` literal with
|
|
/// parentheses instead of braces, recover the parser state and provide suggestions.
|
|
#[instrument(skip(self, seq, snapshot), level = "trace")]
|
|
fn maybe_recover_struct_lit_bad_delims(
|
|
&mut self,
|
|
lo: Span,
|
|
open_paren: Span,
|
|
seq: &mut PResult<'a, P<Expr>>,
|
|
snapshot: Option<(SnapshotParser<'a>, ExprKind)>,
|
|
) -> Option<P<Expr>> {
|
|
if !self.may_recover() {
|
|
return None;
|
|
}
|
|
match (seq.as_mut(), snapshot) {
|
|
(Err(err), Some((mut snapshot, ExprKind::Path(None, path)))) => {
|
|
snapshot.bump(); // `(`
|
|
match snapshot.parse_struct_fields(path.clone(), false, Delimiter::Parenthesis) {
|
|
Ok((fields, ..))
|
|
if snapshot.eat(&token::CloseDelim(Delimiter::Parenthesis)) =>
|
|
{
|
|
// We are certain we have `Enum::Foo(a: 3, b: 4)`, suggest
|
|
// `Enum::Foo { a: 3, b: 4 }` or `Enum::Foo(3, 4)`.
|
|
self.restore_snapshot(snapshot);
|
|
let close_paren = self.prev_token.span;
|
|
let span = lo.to(close_paren);
|
|
// filter shorthand fields
|
|
let fields: Vec<_> =
|
|
fields.into_iter().filter(|field| !field.is_shorthand).collect();
|
|
|
|
if !fields.is_empty() &&
|
|
// `token.kind` should not be compared here.
|
|
// This is because the `snapshot.token.kind` is treated as the same as
|
|
// that of the open delim in `TokenTreesReader::parse_token_tree`, even if they are different.
|
|
self.span_to_snippet(close_paren).is_ok_and(|snippet| snippet == ")")
|
|
{
|
|
let mut replacement_err =
|
|
self.dcx().create_err(errors::ParenthesesWithStructFields {
|
|
span,
|
|
r#type: path,
|
|
braces_for_struct: errors::BracesForStructLiteral {
|
|
first: open_paren,
|
|
second: close_paren,
|
|
},
|
|
no_fields_for_fn: errors::NoFieldsForFnCall {
|
|
fields: fields
|
|
.into_iter()
|
|
.map(|field| field.span.until(field.expr.span))
|
|
.collect(),
|
|
},
|
|
});
|
|
replacement_err.emit();
|
|
|
|
let old_err = mem::replace(err, replacement_err);
|
|
old_err.cancel();
|
|
} else {
|
|
err.emit();
|
|
}
|
|
return Some(self.mk_expr_err(span));
|
|
}
|
|
Ok(_) => {}
|
|
Err(err) => err.cancel(),
|
|
}
|
|
}
|
|
_ => {}
|
|
}
|
|
None
|
|
}
|
|
|
|
/// Parse an indexing expression `expr[...]`.
|
|
fn parse_expr_index(&mut self, lo: Span, base: P<Expr>) -> PResult<'a, P<Expr>> {
|
|
let prev_span = self.prev_token.span;
|
|
let open_delim_span = self.token.span;
|
|
self.bump(); // `[`
|
|
let index = self.parse_expr()?;
|
|
self.suggest_missing_semicolon_before_array(prev_span, open_delim_span)?;
|
|
self.expect(&token::CloseDelim(Delimiter::Bracket))?;
|
|
Ok(self.mk_expr(
|
|
lo.to(self.prev_token.span),
|
|
self.mk_index(base, index, open_delim_span.to(self.prev_token.span)),
|
|
))
|
|
}
|
|
|
|
/// Assuming we have just parsed `.`, continue parsing into an expression.
|
|
fn parse_dot_suffix(&mut self, self_arg: P<Expr>, lo: Span) -> PResult<'a, P<Expr>> {
|
|
if self.token.uninterpolated_span().at_least_rust_2018() && self.eat_keyword(kw::Await) {
|
|
return Ok(self.mk_await_expr(self_arg, lo));
|
|
}
|
|
|
|
let fn_span_lo = self.token.span;
|
|
let mut seg = self.parse_path_segment(PathStyle::Expr, None)?;
|
|
self.check_trailing_angle_brackets(&seg, &[&token::OpenDelim(Delimiter::Parenthesis)]);
|
|
self.check_turbofish_missing_angle_brackets(&mut seg);
|
|
|
|
if self.check(&token::OpenDelim(Delimiter::Parenthesis)) {
|
|
// Method call `expr.f()`
|
|
let args = self.parse_expr_paren_seq()?;
|
|
let fn_span = fn_span_lo.to(self.prev_token.span);
|
|
let span = lo.to(self.prev_token.span);
|
|
Ok(self.mk_expr(
|
|
span,
|
|
ExprKind::MethodCall(Box::new(ast::MethodCall {
|
|
seg,
|
|
receiver: self_arg,
|
|
args,
|
|
span: fn_span,
|
|
})),
|
|
))
|
|
} else {
|
|
// Field access `expr.f`
|
|
if let Some(args) = seg.args {
|
|
self.sess.emit_err(errors::FieldExpressionWithGeneric(args.span()));
|
|
}
|
|
|
|
let span = lo.to(self.prev_token.span);
|
|
Ok(self.mk_expr(span, ExprKind::Field(self_arg, seg.ident)))
|
|
}
|
|
}
|
|
|
|
/// At the bottom (top?) of the precedence hierarchy,
|
|
/// Parses things like parenthesized exprs, macros, `return`, etc.
|
|
///
|
|
/// N.B., this does not parse outer attributes, and is private because it only works
|
|
/// correctly if called from `parse_dot_or_call_expr()`.
|
|
fn parse_expr_bottom(&mut self) -> PResult<'a, P<Expr>> {
|
|
maybe_recover_from_interpolated_ty_qpath!(self, true);
|
|
maybe_whole_expr!(self);
|
|
|
|
// Outer attributes are already parsed and will be
|
|
// added to the return value after the fact.
|
|
|
|
let restrictions = self.restrictions;
|
|
self.with_res(restrictions - Restrictions::ALLOW_LET, |this| {
|
|
// Note: when adding new syntax here, don't forget to adjust `TokenKind::can_begin_expr()`.
|
|
let lo = this.token.span;
|
|
if let token::Literal(_) = this.token.kind {
|
|
// This match arm is a special-case of the `_` match arm below and
|
|
// could be removed without changing functionality, but it's faster
|
|
// to have it here, especially for programs with large constants.
|
|
this.parse_expr_lit()
|
|
} else if this.check(&token::OpenDelim(Delimiter::Parenthesis)) {
|
|
this.parse_expr_tuple_parens(restrictions)
|
|
} else if this.check(&token::OpenDelim(Delimiter::Brace)) {
|
|
this.parse_expr_block(None, lo, BlockCheckMode::Default)
|
|
} else if this.check(&token::BinOp(token::Or)) || this.check(&token::OrOr) {
|
|
this.parse_expr_closure().map_err(|mut err| {
|
|
// If the input is something like `if a { 1 } else { 2 } | if a { 3 } else { 4 }`
|
|
// then suggest parens around the lhs.
|
|
if let Some(sp) = this.sess.ambiguous_block_expr_parse.borrow().get(&lo) {
|
|
err.subdiagnostic(ExprParenthesesNeeded::surrounding(*sp));
|
|
}
|
|
err
|
|
})
|
|
} else if this.check(&token::OpenDelim(Delimiter::Bracket)) {
|
|
this.parse_expr_array_or_repeat(Delimiter::Bracket)
|
|
} else if this.is_builtin() {
|
|
this.parse_expr_builtin()
|
|
} else if this.check_path() {
|
|
this.parse_expr_path_start()
|
|
} else if this.check_keyword(kw::Move)
|
|
|| this.check_keyword(kw::Static)
|
|
|| this.check_const_closure()
|
|
{
|
|
this.parse_expr_closure()
|
|
} else if this.eat_keyword(kw::If) {
|
|
this.parse_expr_if()
|
|
} else if this.check_keyword(kw::For) {
|
|
if this.choose_generics_over_qpath(1) {
|
|
this.parse_expr_closure()
|
|
} else {
|
|
assert!(this.eat_keyword(kw::For));
|
|
this.parse_expr_for(None, this.prev_token.span)
|
|
}
|
|
} else if this.eat_keyword(kw::While) {
|
|
this.parse_expr_while(None, this.prev_token.span)
|
|
} else if let Some(label) = this.eat_label() {
|
|
this.parse_expr_labeled(label, true)
|
|
} else if this.eat_keyword(kw::Loop) {
|
|
let sp = this.prev_token.span;
|
|
this.parse_expr_loop(None, this.prev_token.span).map_err(|mut err| {
|
|
err.span_label(sp, "while parsing this `loop` expression");
|
|
err
|
|
})
|
|
} else if this.eat_keyword(kw::Match) {
|
|
let match_sp = this.prev_token.span;
|
|
this.parse_expr_match().map_err(|mut err| {
|
|
err.span_label(match_sp, "while parsing this `match` expression");
|
|
err
|
|
})
|
|
} else if this.eat_keyword(kw::Unsafe) {
|
|
let sp = this.prev_token.span;
|
|
this.parse_expr_block(None, lo, BlockCheckMode::Unsafe(ast::UserProvided)).map_err(
|
|
|mut err| {
|
|
err.span_label(sp, "while parsing this `unsafe` expression");
|
|
err
|
|
},
|
|
)
|
|
} else if this.check_inline_const(0) {
|
|
this.parse_const_block(lo.to(this.token.span), false)
|
|
} else if this.may_recover() && this.is_do_catch_block() {
|
|
this.recover_do_catch()
|
|
} else if this.is_try_block() {
|
|
this.expect_keyword(kw::Try)?;
|
|
this.parse_try_block(lo)
|
|
} else if this.eat_keyword(kw::Return) {
|
|
this.parse_expr_return()
|
|
} else if this.eat_keyword(kw::Continue) {
|
|
this.parse_expr_continue(lo)
|
|
} else if this.eat_keyword(kw::Break) {
|
|
this.parse_expr_break()
|
|
} else if this.eat_keyword(kw::Yield) {
|
|
this.parse_expr_yield()
|
|
} else if this.is_do_yeet() {
|
|
this.parse_expr_yeet()
|
|
} else if this.eat_keyword(kw::Become) {
|
|
this.parse_expr_become()
|
|
} else if this.check_keyword(kw::Let) {
|
|
this.parse_expr_let(restrictions)
|
|
} else if this.eat_keyword(kw::Underscore) {
|
|
Ok(this.mk_expr(this.prev_token.span, ExprKind::Underscore))
|
|
} else if this.token.uninterpolated_span().at_least_rust_2018() {
|
|
// `Span::at_least_rust_2018()` is somewhat expensive; don't get it repeatedly.
|
|
if this.token.uninterpolated_span().at_least_rust_2024()
|
|
// check for `gen {}` and `gen move {}`
|
|
// or `async gen {}` and `async gen move {}`
|
|
&& (this.is_gen_block(kw::Gen, 0)
|
|
|| (this.check_keyword(kw::Async) && this.is_gen_block(kw::Gen, 1)))
|
|
{
|
|
// FIXME: (async) gen closures aren't yet parsed.
|
|
this.parse_gen_block()
|
|
} else if this.check_keyword(kw::Async) {
|
|
// FIXME(gen_blocks): Parse `gen async` and suggest swap
|
|
if this.is_gen_block(kw::Async, 0) {
|
|
// Check for `async {` and `async move {`,
|
|
this.parse_gen_block()
|
|
} else {
|
|
this.parse_expr_closure()
|
|
}
|
|
} else if this.eat_keyword_noexpect(kw::Await) {
|
|
this.recover_incorrect_await_syntax(lo, this.prev_token.span)
|
|
} else {
|
|
this.parse_expr_lit()
|
|
}
|
|
} else {
|
|
this.parse_expr_lit()
|
|
}
|
|
})
|
|
}
|
|
|
|
fn parse_expr_lit(&mut self) -> PResult<'a, P<Expr>> {
|
|
let lo = self.token.span;
|
|
match self.parse_opt_token_lit() {
|
|
Some((token_lit, _)) => {
|
|
let expr = self.mk_expr(lo.to(self.prev_token.span), ExprKind::Lit(token_lit));
|
|
self.maybe_recover_from_bad_qpath(expr)
|
|
}
|
|
None => self.try_macro_suggestion(),
|
|
}
|
|
}
|
|
|
|
fn parse_expr_tuple_parens(&mut self, restrictions: Restrictions) -> PResult<'a, P<Expr>> {
|
|
let lo = self.token.span;
|
|
self.expect(&token::OpenDelim(Delimiter::Parenthesis))?;
|
|
let (es, trailing_comma) = match self.parse_seq_to_end(
|
|
&token::CloseDelim(Delimiter::Parenthesis),
|
|
SeqSep::trailing_allowed(token::Comma),
|
|
|p| p.parse_expr_catch_underscore(restrictions.intersection(Restrictions::ALLOW_LET)),
|
|
) {
|
|
Ok(x) => x,
|
|
Err(err) => {
|
|
return Ok(self.recover_seq_parse_error(Delimiter::Parenthesis, lo, Err(err)));
|
|
}
|
|
};
|
|
let kind = if es.len() == 1 && !trailing_comma {
|
|
// `(e)` is parenthesized `e`.
|
|
ExprKind::Paren(es.into_iter().next().unwrap())
|
|
} else {
|
|
// `(e,)` is a tuple with only one field, `e`.
|
|
ExprKind::Tup(es)
|
|
};
|
|
let expr = self.mk_expr(lo.to(self.prev_token.span), kind);
|
|
self.maybe_recover_from_bad_qpath(expr)
|
|
}
|
|
|
|
fn parse_expr_array_or_repeat(&mut self, close_delim: Delimiter) -> PResult<'a, P<Expr>> {
|
|
let lo = self.token.span;
|
|
self.bump(); // `[` or other open delim
|
|
|
|
let close = &token::CloseDelim(close_delim);
|
|
let kind = if self.eat(close) {
|
|
// Empty vector
|
|
ExprKind::Array(ThinVec::new())
|
|
} else {
|
|
// Non-empty vector
|
|
let first_expr = self.parse_expr()?;
|
|
if self.eat(&token::Semi) {
|
|
// Repeating array syntax: `[ 0; 512 ]`
|
|
let count = self.parse_expr_anon_const()?;
|
|
self.expect(close)?;
|
|
ExprKind::Repeat(first_expr, count)
|
|
} else if self.eat(&token::Comma) {
|
|
// Vector with two or more elements.
|
|
let sep = SeqSep::trailing_allowed(token::Comma);
|
|
let (mut exprs, _) = self.parse_seq_to_end(close, sep, |p| p.parse_expr())?;
|
|
exprs.insert(0, first_expr);
|
|
ExprKind::Array(exprs)
|
|
} else {
|
|
// Vector with one element
|
|
self.expect(close)?;
|
|
ExprKind::Array(thin_vec![first_expr])
|
|
}
|
|
};
|
|
let expr = self.mk_expr(lo.to(self.prev_token.span), kind);
|
|
self.maybe_recover_from_bad_qpath(expr)
|
|
}
|
|
|
|
fn parse_expr_path_start(&mut self) -> PResult<'a, P<Expr>> {
|
|
let maybe_eq_tok = self.prev_token.clone();
|
|
let (qself, path) = if self.eat_lt() {
|
|
let lt_span = self.prev_token.span;
|
|
let (qself, path) = self.parse_qpath(PathStyle::Expr).map_err(|mut err| {
|
|
// Suggests using '<=' if there is an error parsing qpath when the previous token
|
|
// is an '=' token. Only emits suggestion if the '<' token and '=' token are
|
|
// directly adjacent (i.e. '=<')
|
|
if maybe_eq_tok.kind == TokenKind::Eq && maybe_eq_tok.span.hi() == lt_span.lo() {
|
|
let eq_lt = maybe_eq_tok.span.to(lt_span);
|
|
err.span_suggestion(eq_lt, "did you mean", "<=", Applicability::Unspecified);
|
|
}
|
|
err
|
|
})?;
|
|
(Some(qself), path)
|
|
} else {
|
|
(None, self.parse_path(PathStyle::Expr)?)
|
|
};
|
|
|
|
// `!`, as an operator, is prefix, so we know this isn't that.
|
|
let (span, kind) = if self.eat(&token::Not) {
|
|
// MACRO INVOCATION expression
|
|
if qself.is_some() {
|
|
self.sess.emit_err(errors::MacroInvocationWithQualifiedPath(path.span));
|
|
}
|
|
let lo = path.span;
|
|
let mac = P(MacCall { path, args: self.parse_delim_args()? });
|
|
(lo.to(self.prev_token.span), ExprKind::MacCall(mac))
|
|
} else if self.check(&token::OpenDelim(Delimiter::Brace))
|
|
&& let Some(expr) = self.maybe_parse_struct_expr(&qself, &path)
|
|
{
|
|
if qself.is_some() {
|
|
self.sess.gated_spans.gate(sym::more_qualified_paths, path.span);
|
|
}
|
|
return expr;
|
|
} else {
|
|
(path.span, ExprKind::Path(qself, path))
|
|
};
|
|
|
|
let expr = self.mk_expr(span, kind);
|
|
self.maybe_recover_from_bad_qpath(expr)
|
|
}
|
|
|
|
/// Parse `'label: $expr`. The label is already parsed.
|
|
pub(super) fn parse_expr_labeled(
|
|
&mut self,
|
|
label_: Label,
|
|
mut consume_colon: bool,
|
|
) -> PResult<'a, P<Expr>> {
|
|
let lo = label_.ident.span;
|
|
let label = Some(label_);
|
|
let ate_colon = self.eat(&token::Colon);
|
|
let expr = if self.eat_keyword(kw::While) {
|
|
self.parse_expr_while(label, lo)
|
|
} else if self.eat_keyword(kw::For) {
|
|
self.parse_expr_for(label, lo)
|
|
} else if self.eat_keyword(kw::Loop) {
|
|
self.parse_expr_loop(label, lo)
|
|
} else if self.check_noexpect(&token::OpenDelim(Delimiter::Brace))
|
|
|| self.token.is_whole_block()
|
|
{
|
|
self.parse_expr_block(label, lo, BlockCheckMode::Default)
|
|
} else if !ate_colon
|
|
&& self.may_recover()
|
|
&& (matches!(self.token.kind, token::CloseDelim(_) | token::Comma)
|
|
|| self.token.is_punct())
|
|
{
|
|
let (lit, _) =
|
|
self.recover_unclosed_char(label_.ident, Parser::mk_token_lit_char, |self_| {
|
|
self_.sess.create_err(errors::UnexpectedTokenAfterLabel {
|
|
span: self_.token.span,
|
|
remove_label: None,
|
|
enclose_in_block: None,
|
|
})
|
|
});
|
|
consume_colon = false;
|
|
Ok(self.mk_expr(lo, ExprKind::Lit(lit)))
|
|
} else if !ate_colon
|
|
&& (self.check_noexpect(&TokenKind::Comma) || self.check_noexpect(&TokenKind::Gt))
|
|
{
|
|
// We're probably inside of a `Path<'a>` that needs a turbofish
|
|
self.sess.emit_err(errors::UnexpectedTokenAfterLabel {
|
|
span: self.token.span,
|
|
remove_label: None,
|
|
enclose_in_block: None,
|
|
});
|
|
consume_colon = false;
|
|
Ok(self.mk_expr_err(lo))
|
|
} else {
|
|
let mut err = errors::UnexpectedTokenAfterLabel {
|
|
span: self.token.span,
|
|
remove_label: None,
|
|
enclose_in_block: None,
|
|
};
|
|
|
|
// Continue as an expression in an effort to recover on `'label: non_block_expr`.
|
|
let expr = self.parse_expr().map(|expr| {
|
|
let span = expr.span;
|
|
|
|
let found_labeled_breaks = {
|
|
struct FindLabeledBreaksVisitor(bool);
|
|
|
|
impl<'ast> Visitor<'ast> for FindLabeledBreaksVisitor {
|
|
fn visit_expr_post(&mut self, ex: &'ast Expr) {
|
|
if let ExprKind::Break(Some(_label), _) = ex.kind {
|
|
self.0 = true;
|
|
}
|
|
}
|
|
}
|
|
|
|
let mut vis = FindLabeledBreaksVisitor(false);
|
|
vis.visit_expr(&expr);
|
|
vis.0
|
|
};
|
|
|
|
// Suggestion involves adding a labeled block.
|
|
//
|
|
// If there are no breaks that may use this label, suggest removing the label and
|
|
// recover to the unmodified expression.
|
|
if !found_labeled_breaks {
|
|
err.remove_label = Some(lo.until(span));
|
|
|
|
return expr;
|
|
}
|
|
|
|
err.enclose_in_block = Some(errors::UnexpectedTokenAfterLabelSugg {
|
|
left: span.shrink_to_lo(),
|
|
right: span.shrink_to_hi(),
|
|
});
|
|
|
|
// Replace `'label: non_block_expr` with `'label: {non_block_expr}` in order to suppress future errors about `break 'label`.
|
|
let stmt = self.mk_stmt(span, StmtKind::Expr(expr));
|
|
let blk = self.mk_block(thin_vec![stmt], BlockCheckMode::Default, span);
|
|
self.mk_expr(span, ExprKind::Block(blk, label))
|
|
});
|
|
|
|
self.sess.emit_err(err);
|
|
expr
|
|
}?;
|
|
|
|
if !ate_colon && consume_colon {
|
|
self.sess.emit_err(errors::RequireColonAfterLabeledExpression {
|
|
span: expr.span,
|
|
label: lo,
|
|
label_end: lo.shrink_to_hi(),
|
|
});
|
|
}
|
|
|
|
Ok(expr)
|
|
}
|
|
|
|
/// Emit an error when a char is parsed as a lifetime because of a missing quote.
|
|
pub(super) fn recover_unclosed_char<L>(
|
|
&self,
|
|
lifetime: Ident,
|
|
mk_lit_char: impl FnOnce(Symbol, Span) -> L,
|
|
err: impl FnOnce(&Self) -> DiagnosticBuilder<'a>,
|
|
) -> L {
|
|
if let Some(mut diag) = self.dcx().steal_diagnostic(lifetime.span, StashKey::LifetimeIsChar)
|
|
{
|
|
diag.span_suggestion_verbose(
|
|
lifetime.span.shrink_to_hi(),
|
|
"add `'` to close the char literal",
|
|
"'",
|
|
Applicability::MaybeIncorrect,
|
|
)
|
|
.emit();
|
|
} else {
|
|
err(self)
|
|
.span_suggestion_verbose(
|
|
lifetime.span.shrink_to_hi(),
|
|
"add `'` to close the char literal",
|
|
"'",
|
|
Applicability::MaybeIncorrect,
|
|
)
|
|
.emit();
|
|
}
|
|
let name = lifetime.without_first_quote().name;
|
|
mk_lit_char(name, lifetime.span)
|
|
}
|
|
|
|
/// Recover on the syntax `do catch { ... }` suggesting `try { ... }` instead.
|
|
fn recover_do_catch(&mut self) -> PResult<'a, P<Expr>> {
|
|
let lo = self.token.span;
|
|
|
|
self.bump(); // `do`
|
|
self.bump(); // `catch`
|
|
|
|
let span = lo.to(self.prev_token.span);
|
|
self.sess.emit_err(errors::DoCatchSyntaxRemoved { span });
|
|
|
|
self.parse_try_block(lo)
|
|
}
|
|
|
|
/// Parse an expression if the token can begin one.
|
|
fn parse_expr_opt(&mut self) -> PResult<'a, Option<P<Expr>>> {
|
|
Ok(if self.token.can_begin_expr() { Some(self.parse_expr()?) } else { None })
|
|
}
|
|
|
|
/// Parse `"return" expr?`.
|
|
fn parse_expr_return(&mut self) -> PResult<'a, P<Expr>> {
|
|
let lo = self.prev_token.span;
|
|
let kind = ExprKind::Ret(self.parse_expr_opt()?);
|
|
let expr = self.mk_expr(lo.to(self.prev_token.span), kind);
|
|
self.maybe_recover_from_bad_qpath(expr)
|
|
}
|
|
|
|
/// Parse `"do" "yeet" expr?`.
|
|
fn parse_expr_yeet(&mut self) -> PResult<'a, P<Expr>> {
|
|
let lo = self.token.span;
|
|
|
|
self.bump(); // `do`
|
|
self.bump(); // `yeet`
|
|
|
|
let kind = ExprKind::Yeet(self.parse_expr_opt()?);
|
|
|
|
let span = lo.to(self.prev_token.span);
|
|
self.sess.gated_spans.gate(sym::yeet_expr, span);
|
|
let expr = self.mk_expr(span, kind);
|
|
self.maybe_recover_from_bad_qpath(expr)
|
|
}
|
|
|
|
/// Parse `"become" expr`, with `"become"` token already eaten.
|
|
fn parse_expr_become(&mut self) -> PResult<'a, P<Expr>> {
|
|
let lo = self.prev_token.span;
|
|
let kind = ExprKind::Become(self.parse_expr()?);
|
|
let span = lo.to(self.prev_token.span);
|
|
self.sess.gated_spans.gate(sym::explicit_tail_calls, span);
|
|
let expr = self.mk_expr(span, kind);
|
|
self.maybe_recover_from_bad_qpath(expr)
|
|
}
|
|
|
|
/// Parse `"break" (('label (:? expr)?) | expr?)` with `"break"` token already eaten.
|
|
/// If the label is followed immediately by a `:` token, the label and `:` are
|
|
/// parsed as part of the expression (i.e. a labeled loop). The language team has
|
|
/// decided in #87026 to require parentheses as a visual aid to avoid confusion if
|
|
/// the break expression of an unlabeled break is a labeled loop (as in
|
|
/// `break 'lbl: loop {}`); a labeled break with an unlabeled loop as its value
|
|
/// expression only gets a warning for compatibility reasons; and a labeled break
|
|
/// with a labeled loop does not even get a warning because there is no ambiguity.
|
|
fn parse_expr_break(&mut self) -> PResult<'a, P<Expr>> {
|
|
let lo = self.prev_token.span;
|
|
let mut label = self.eat_label();
|
|
let kind = if self.token == token::Colon
|
|
&& let Some(label) = label.take()
|
|
{
|
|
// The value expression can be a labeled loop, see issue #86948, e.g.:
|
|
// `loop { break 'label: loop { break 'label 42; }; }`
|
|
let lexpr = self.parse_expr_labeled(label, true)?;
|
|
self.sess.emit_err(errors::LabeledLoopInBreak {
|
|
span: lexpr.span,
|
|
sub: errors::WrapExpressionInParentheses {
|
|
left: lexpr.span.shrink_to_lo(),
|
|
right: lexpr.span.shrink_to_hi(),
|
|
},
|
|
});
|
|
Some(lexpr)
|
|
} else if self.token != token::OpenDelim(Delimiter::Brace)
|
|
|| !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL)
|
|
{
|
|
let mut expr = self.parse_expr_opt()?;
|
|
if let Some(expr) = &mut expr {
|
|
if label.is_some()
|
|
&& matches!(
|
|
expr.kind,
|
|
ExprKind::While(_, _, None)
|
|
| ExprKind::ForLoop { label: None, .. }
|
|
| ExprKind::Loop(_, None, _)
|
|
| ExprKind::Block(_, None)
|
|
)
|
|
{
|
|
self.sess.buffer_lint_with_diagnostic(
|
|
BREAK_WITH_LABEL_AND_LOOP,
|
|
lo.to(expr.span),
|
|
ast::CRATE_NODE_ID,
|
|
"this labeled break expression is easy to confuse with an unlabeled break with a labeled value expression",
|
|
BuiltinLintDiagnostics::BreakWithLabelAndLoop(expr.span),
|
|
);
|
|
}
|
|
|
|
// Recover `break label aaaaa`
|
|
if self.may_recover()
|
|
&& let ExprKind::Path(None, p) = &expr.kind
|
|
&& let [segment] = &*p.segments
|
|
&& let &ast::PathSegment { ident, args: None, .. } = segment
|
|
&& let Some(next) = self.parse_expr_opt()?
|
|
{
|
|
label = Some(self.recover_ident_into_label(ident));
|
|
*expr = next;
|
|
}
|
|
}
|
|
|
|
expr
|
|
} else {
|
|
None
|
|
};
|
|
let expr = self.mk_expr(lo.to(self.prev_token.span), ExprKind::Break(label, kind));
|
|
self.maybe_recover_from_bad_qpath(expr)
|
|
}
|
|
|
|
/// Parse `"continue" label?`.
|
|
fn parse_expr_continue(&mut self, lo: Span) -> PResult<'a, P<Expr>> {
|
|
let mut label = self.eat_label();
|
|
|
|
// Recover `continue label` -> `continue 'label`
|
|
if self.may_recover()
|
|
&& label.is_none()
|
|
&& let Some((ident, _)) = self.token.ident()
|
|
{
|
|
self.bump();
|
|
label = Some(self.recover_ident_into_label(ident));
|
|
}
|
|
|
|
let kind = ExprKind::Continue(label);
|
|
Ok(self.mk_expr(lo.to(self.prev_token.span), kind))
|
|
}
|
|
|
|
/// Parse `"yield" expr?`.
|
|
fn parse_expr_yield(&mut self) -> PResult<'a, P<Expr>> {
|
|
let lo = self.prev_token.span;
|
|
let kind = ExprKind::Yield(self.parse_expr_opt()?);
|
|
let span = lo.to(self.prev_token.span);
|
|
self.sess.gated_spans.gate(sym::yield_expr, span);
|
|
let expr = self.mk_expr(span, kind);
|
|
self.maybe_recover_from_bad_qpath(expr)
|
|
}
|
|
|
|
/// Parse `builtin # ident(args,*)`.
|
|
fn parse_expr_builtin(&mut self) -> PResult<'a, P<Expr>> {
|
|
self.parse_builtin(|this, lo, ident| {
|
|
if ident.name == sym::offset_of {
|
|
return Ok(Some(this.parse_expr_offset_of(lo)?));
|
|
}
|
|
|
|
Ok(None)
|
|
})
|
|
}
|
|
|
|
pub(crate) fn parse_builtin<T>(
|
|
&mut self,
|
|
parse: impl FnOnce(&mut Parser<'a>, Span, Ident) -> PResult<'a, Option<T>>,
|
|
) -> PResult<'a, T> {
|
|
let lo = self.token.span;
|
|
|
|
self.bump(); // `builtin`
|
|
self.bump(); // `#`
|
|
|
|
let Some((ident, false)) = self.token.ident() else {
|
|
let err = self.dcx().create_err(errors::ExpectedBuiltinIdent { span: self.token.span });
|
|
return Err(err);
|
|
};
|
|
self.sess.gated_spans.gate(sym::builtin_syntax, ident.span);
|
|
self.bump();
|
|
|
|
self.expect(&TokenKind::OpenDelim(Delimiter::Parenthesis))?;
|
|
let ret = if let Some(res) = parse(self, lo, ident)? {
|
|
Ok(res)
|
|
} else {
|
|
let err = self.dcx().create_err(errors::UnknownBuiltinConstruct {
|
|
span: lo.to(ident.span),
|
|
name: ident.name,
|
|
});
|
|
return Err(err);
|
|
};
|
|
self.expect(&TokenKind::CloseDelim(Delimiter::Parenthesis))?;
|
|
|
|
ret
|
|
}
|
|
|
|
pub(crate) fn parse_expr_offset_of(&mut self, lo: Span) -> PResult<'a, P<Expr>> {
|
|
let container = self.parse_ty()?;
|
|
self.expect(&TokenKind::Comma)?;
|
|
|
|
let seq_sep = SeqSep { sep: Some(token::Dot), trailing_sep_allowed: false };
|
|
let (fields, _trailing, _recovered) = self.parse_seq_to_before_end(
|
|
&TokenKind::CloseDelim(Delimiter::Parenthesis),
|
|
seq_sep,
|
|
Parser::parse_field_name_maybe_tuple,
|
|
)?;
|
|
let fields = fields.into_iter().flatten().collect::<Vec<_>>();
|
|
let span = lo.to(self.token.span);
|
|
Ok(self.mk_expr(span, ExprKind::OffsetOf(container, fields.into())))
|
|
}
|
|
|
|
/// Returns a string literal if the next token is a string literal.
|
|
/// In case of error returns `Some(lit)` if the next token is a literal with a wrong kind,
|
|
/// and returns `None` if the next token is not literal at all.
|
|
pub fn parse_str_lit(&mut self) -> Result<ast::StrLit, Option<MetaItemLit>> {
|
|
match self.parse_opt_meta_item_lit() {
|
|
Some(lit) => match lit.kind {
|
|
ast::LitKind::Str(symbol_unescaped, style) => Ok(ast::StrLit {
|
|
style,
|
|
symbol: lit.symbol,
|
|
suffix: lit.suffix,
|
|
span: lit.span,
|
|
symbol_unescaped,
|
|
}),
|
|
_ => Err(Some(lit)),
|
|
},
|
|
None => Err(None),
|
|
}
|
|
}
|
|
|
|
pub(crate) fn mk_token_lit_char(name: Symbol, span: Span) -> (token::Lit, Span) {
|
|
(token::Lit { symbol: name, suffix: None, kind: token::Char }, span)
|
|
}
|
|
|
|
fn mk_meta_item_lit_char(name: Symbol, span: Span) -> MetaItemLit {
|
|
ast::MetaItemLit {
|
|
symbol: name,
|
|
suffix: None,
|
|
kind: ast::LitKind::Char(name.as_str().chars().next().unwrap_or('_')),
|
|
span,
|
|
}
|
|
}
|
|
|
|
fn handle_missing_lit<L>(
|
|
&mut self,
|
|
mk_lit_char: impl FnOnce(Symbol, Span) -> L,
|
|
) -> PResult<'a, L> {
|
|
if let token::Interpolated(nt) = &self.token.kind
|
|
&& let token::NtExpr(e) | token::NtLiteral(e) = &nt.0
|
|
&& matches!(e.kind, ExprKind::Err)
|
|
{
|
|
let mut err = self
|
|
.dcx()
|
|
.create_err(errors::InvalidInterpolatedExpression { span: self.token.span });
|
|
err.downgrade_to_delayed_bug();
|
|
return Err(err);
|
|
}
|
|
let token = self.token.clone();
|
|
let err = |self_: &Self| {
|
|
let msg = format!("unexpected token: {}", super::token_descr(&token));
|
|
self_.dcx().struct_span_err(token.span, msg)
|
|
};
|
|
// On an error path, eagerly consider a lifetime to be an unclosed character lit
|
|
if self.token.is_lifetime() {
|
|
let lt = self.expect_lifetime();
|
|
Ok(self.recover_unclosed_char(lt.ident, mk_lit_char, err))
|
|
} else {
|
|
Err(err(self))
|
|
}
|
|
}
|
|
|
|
pub(super) fn parse_token_lit(&mut self) -> PResult<'a, (token::Lit, Span)> {
|
|
self.parse_opt_token_lit()
|
|
.ok_or(())
|
|
.or_else(|()| self.handle_missing_lit(Parser::mk_token_lit_char))
|
|
}
|
|
|
|
pub(super) fn parse_meta_item_lit(&mut self) -> PResult<'a, MetaItemLit> {
|
|
self.parse_opt_meta_item_lit()
|
|
.ok_or(())
|
|
.or_else(|()| self.handle_missing_lit(Parser::mk_meta_item_lit_char))
|
|
}
|
|
|
|
fn recover_after_dot(&mut self) -> Option<Token> {
|
|
let mut recovered = None;
|
|
if self.token == token::Dot {
|
|
// Attempt to recover `.4` as `0.4`. We don't currently have any syntax where
|
|
// dot would follow an optional literal, so we do this unconditionally.
|
|
recovered = self.look_ahead(1, |next_token| {
|
|
if let token::Literal(token::Lit { kind: token::Integer, symbol, suffix }) =
|
|
next_token.kind
|
|
{
|
|
// If this integer looks like a float, then recover as such.
|
|
//
|
|
// We will never encounter the exponent part of a floating
|
|
// point literal here, since there's no use of the exponent
|
|
// syntax that also constitutes a valid integer, so we need
|
|
// not check for that.
|
|
if suffix.map_or(true, |s| s == sym::f32 || s == sym::f64)
|
|
&& symbol.as_str().chars().all(|c| c.is_numeric() || c == '_')
|
|
&& self.token.span.hi() == next_token.span.lo()
|
|
{
|
|
let s = String::from("0.") + symbol.as_str();
|
|
let kind = TokenKind::lit(token::Float, Symbol::intern(&s), suffix);
|
|
return Some(Token::new(kind, self.token.span.to(next_token.span)));
|
|
}
|
|
}
|
|
None
|
|
});
|
|
if let Some(token) = &recovered {
|
|
self.bump();
|
|
self.sess.emit_err(errors::FloatLiteralRequiresIntegerPart {
|
|
span: token.span,
|
|
correct: pprust::token_to_string(token).into_owned(),
|
|
});
|
|
}
|
|
}
|
|
|
|
recovered
|
|
}
|
|
|
|
/// Matches `lit = true | false | token_lit`.
|
|
/// Returns `None` if the next token is not a literal.
|
|
pub(super) fn parse_opt_token_lit(&mut self) -> Option<(token::Lit, Span)> {
|
|
let recovered = self.recover_after_dot();
|
|
let token = recovered.as_ref().unwrap_or(&self.token);
|
|
let span = token.span;
|
|
|
|
token::Lit::from_token(token).map(|token_lit| {
|
|
self.bump();
|
|
(token_lit, span)
|
|
})
|
|
}
|
|
|
|
/// Matches `lit = true | false | token_lit`.
|
|
/// Returns `None` if the next token is not a literal.
|
|
pub(super) fn parse_opt_meta_item_lit(&mut self) -> Option<MetaItemLit> {
|
|
let recovered = self.recover_after_dot();
|
|
let token = recovered.as_ref().unwrap_or(&self.token);
|
|
match token::Lit::from_token(token) {
|
|
Some(lit) => {
|
|
match MetaItemLit::from_token_lit(lit, token.span) {
|
|
Ok(lit) => {
|
|
self.bump();
|
|
Some(lit)
|
|
}
|
|
Err(err) => {
|
|
let span = token.uninterpolated_span();
|
|
self.bump();
|
|
report_lit_error(self.sess, err, lit, span);
|
|
// Pack possible quotes and prefixes from the original literal into
|
|
// the error literal's symbol so they can be pretty-printed faithfully.
|
|
let suffixless_lit = token::Lit::new(lit.kind, lit.symbol, None);
|
|
let symbol = Symbol::intern(&suffixless_lit.to_string());
|
|
let lit = token::Lit::new(token::Err, symbol, lit.suffix);
|
|
Some(
|
|
MetaItemLit::from_token_lit(lit, span)
|
|
.unwrap_or_else(|_| unreachable!()),
|
|
)
|
|
}
|
|
}
|
|
}
|
|
None => None,
|
|
}
|
|
}
|
|
|
|
pub(super) fn expect_no_tuple_index_suffix(&self, span: Span, suffix: Symbol) {
|
|
if [sym::i32, sym::u32, sym::isize, sym::usize].contains(&suffix) {
|
|
// #59553: warn instead of reject out of hand to allow the fix to percolate
|
|
// through the ecosystem when people fix their macros
|
|
self.sess.emit_warning(errors::InvalidLiteralSuffixOnTupleIndex {
|
|
span,
|
|
suffix,
|
|
exception: Some(()),
|
|
});
|
|
} else {
|
|
self.sess.emit_err(errors::InvalidLiteralSuffixOnTupleIndex {
|
|
span,
|
|
suffix,
|
|
exception: None,
|
|
});
|
|
}
|
|
}
|
|
|
|
/// Matches `'-' lit | lit` (cf. `ast_validation::AstValidator::check_expr_within_pat`).
|
|
/// Keep this in sync with `Token::can_begin_literal_maybe_minus`.
|
|
pub fn parse_literal_maybe_minus(&mut self) -> PResult<'a, P<Expr>> {
|
|
maybe_whole_expr!(self);
|
|
|
|
let lo = self.token.span;
|
|
let minus_present = self.eat(&token::BinOp(token::Minus));
|
|
let (token_lit, span) = self.parse_token_lit()?;
|
|
let expr = self.mk_expr(span, ExprKind::Lit(token_lit));
|
|
|
|
if minus_present {
|
|
Ok(self.mk_expr(lo.to(self.prev_token.span), self.mk_unary(UnOp::Neg, expr)))
|
|
} else {
|
|
Ok(expr)
|
|
}
|
|
}
|
|
|
|
fn is_array_like_block(&mut self) -> bool {
|
|
self.look_ahead(1, |t| matches!(t.kind, TokenKind::Ident(..) | TokenKind::Literal(_)))
|
|
&& self.look_ahead(2, |t| t == &token::Comma)
|
|
&& self.look_ahead(3, |t| t.can_begin_expr())
|
|
}
|
|
|
|
/// Emits a suggestion if it looks like the user meant an array but
|
|
/// accidentally used braces, causing the code to be interpreted as a block
|
|
/// expression.
|
|
fn maybe_suggest_brackets_instead_of_braces(&mut self, lo: Span) -> Option<P<Expr>> {
|
|
let mut snapshot = self.create_snapshot_for_diagnostic();
|
|
match snapshot.parse_expr_array_or_repeat(Delimiter::Brace) {
|
|
Ok(arr) => {
|
|
self.sess.emit_err(errors::ArrayBracketsInsteadOfSpaces {
|
|
span: arr.span,
|
|
sub: errors::ArrayBracketsInsteadOfSpacesSugg {
|
|
left: lo,
|
|
right: snapshot.prev_token.span,
|
|
},
|
|
});
|
|
|
|
self.restore_snapshot(snapshot);
|
|
Some(self.mk_expr_err(arr.span))
|
|
}
|
|
Err(e) => {
|
|
e.cancel();
|
|
None
|
|
}
|
|
}
|
|
}
|
|
|
|
fn suggest_missing_semicolon_before_array(
|
|
&self,
|
|
prev_span: Span,
|
|
open_delim_span: Span,
|
|
) -> PResult<'a, ()> {
|
|
if !self.may_recover() {
|
|
return Ok(());
|
|
}
|
|
|
|
if self.token.kind == token::Comma {
|
|
if !self.sess.source_map().is_multiline(prev_span.until(self.token.span)) {
|
|
return Ok(());
|
|
}
|
|
let mut snapshot = self.create_snapshot_for_diagnostic();
|
|
snapshot.bump();
|
|
match snapshot.parse_seq_to_before_end(
|
|
&token::CloseDelim(Delimiter::Bracket),
|
|
SeqSep::trailing_allowed(token::Comma),
|
|
|p| p.parse_expr(),
|
|
) {
|
|
Ok(_)
|
|
// When the close delim is `)`, `token.kind` is expected to be `token::CloseDelim(Delimiter::Parenthesis)`,
|
|
// but the actual `token.kind` is `token::CloseDelim(Delimiter::Bracket)`.
|
|
// This is because the `token.kind` of the close delim is treated as the same as
|
|
// that of the open delim in `TokenTreesReader::parse_token_tree`, even if the delimiters of them are different.
|
|
// Therefore, `token.kind` should not be compared here.
|
|
if snapshot
|
|
.span_to_snippet(snapshot.token.span)
|
|
.is_ok_and(|snippet| snippet == "]") =>
|
|
{
|
|
return Err(self.dcx().create_err(errors::MissingSemicolonBeforeArray {
|
|
open_delim: open_delim_span,
|
|
semicolon: prev_span.shrink_to_hi(),
|
|
}));
|
|
}
|
|
Ok(_) => (),
|
|
Err(err) => err.cancel(),
|
|
}
|
|
}
|
|
Ok(())
|
|
}
|
|
|
|
/// Parses a block or unsafe block.
|
|
pub(super) fn parse_expr_block(
|
|
&mut self,
|
|
opt_label: Option<Label>,
|
|
lo: Span,
|
|
blk_mode: BlockCheckMode,
|
|
) -> PResult<'a, P<Expr>> {
|
|
if self.may_recover() && self.is_array_like_block() {
|
|
if let Some(arr) = self.maybe_suggest_brackets_instead_of_braces(lo) {
|
|
return Ok(arr);
|
|
}
|
|
}
|
|
|
|
if self.token.is_whole_block() {
|
|
self.sess.emit_err(errors::InvalidBlockMacroSegment {
|
|
span: self.token.span,
|
|
context: lo.to(self.token.span),
|
|
wrap: errors::WrapInExplicitBlock {
|
|
lo: self.token.span.shrink_to_lo(),
|
|
hi: self.token.span.shrink_to_hi(),
|
|
},
|
|
});
|
|
}
|
|
|
|
let (attrs, blk) = self.parse_block_common(lo, blk_mode, true)?;
|
|
Ok(self.mk_expr_with_attrs(blk.span, ExprKind::Block(blk, opt_label), attrs))
|
|
}
|
|
|
|
/// Parse a block which takes no attributes and has no label
|
|
fn parse_simple_block(&mut self) -> PResult<'a, P<Expr>> {
|
|
let blk = self.parse_block()?;
|
|
Ok(self.mk_expr(blk.span, ExprKind::Block(blk, None)))
|
|
}
|
|
|
|
/// Parses a closure expression (e.g., `move |args| expr`).
|
|
fn parse_expr_closure(&mut self) -> PResult<'a, P<Expr>> {
|
|
let lo = self.token.span;
|
|
|
|
let before = self.prev_token.clone();
|
|
let binder = if self.check_keyword(kw::For) {
|
|
let lo = self.token.span;
|
|
let lifetime_defs = self.parse_late_bound_lifetime_defs()?;
|
|
let span = lo.to(self.prev_token.span);
|
|
|
|
self.sess.gated_spans.gate(sym::closure_lifetime_binder, span);
|
|
|
|
ClosureBinder::For { span, generic_params: lifetime_defs }
|
|
} else {
|
|
ClosureBinder::NotPresent
|
|
};
|
|
|
|
let constness = self.parse_closure_constness();
|
|
|
|
let movability =
|
|
if self.eat_keyword(kw::Static) { Movability::Static } else { Movability::Movable };
|
|
|
|
let coroutine_kind = if self.token.uninterpolated_span().at_least_rust_2018() {
|
|
self.parse_coroutine_kind(Case::Sensitive)
|
|
} else {
|
|
None
|
|
};
|
|
|
|
let capture_clause = self.parse_capture_clause()?;
|
|
let (fn_decl, fn_arg_span) = self.parse_fn_block_decl()?;
|
|
let decl_hi = self.prev_token.span;
|
|
let mut body = match fn_decl.output {
|
|
FnRetTy::Default(_) => {
|
|
let restrictions =
|
|
self.restrictions - Restrictions::STMT_EXPR - Restrictions::ALLOW_LET;
|
|
let prev = self.prev_token.clone();
|
|
let token = self.token.clone();
|
|
match self.parse_expr_res(restrictions, None) {
|
|
Ok(expr) => expr,
|
|
Err(err) => self.recover_closure_body(err, before, prev, token, lo, decl_hi)?,
|
|
}
|
|
}
|
|
_ => {
|
|
// If an explicit return type is given, require a block to appear (RFC 968).
|
|
let body_lo = self.token.span;
|
|
self.parse_expr_block(None, body_lo, BlockCheckMode::Default)?
|
|
}
|
|
};
|
|
|
|
match coroutine_kind {
|
|
Some(CoroutineKind::Async { span, .. }) => {
|
|
// Feature-gate `async ||` closures.
|
|
self.sess.gated_spans.gate(sym::async_closure, span);
|
|
}
|
|
Some(CoroutineKind::Gen { span, .. }) | Some(CoroutineKind::AsyncGen { span, .. }) => {
|
|
// Feature-gate `gen ||` and `async gen ||` closures.
|
|
// FIXME(gen_blocks): This perhaps should be a different gate.
|
|
self.sess.gated_spans.gate(sym::gen_blocks, span);
|
|
}
|
|
None => {}
|
|
}
|
|
|
|
if self.token.kind == TokenKind::Semi
|
|
&& matches!(self.token_cursor.stack.last(), Some((.., Delimiter::Parenthesis)))
|
|
&& self.may_recover()
|
|
{
|
|
// It is likely that the closure body is a block but where the
|
|
// braces have been removed. We will recover and eat the next
|
|
// statements later in the parsing process.
|
|
body = self.mk_expr_err(body.span);
|
|
}
|
|
|
|
let body_span = body.span;
|
|
|
|
let closure = self.mk_expr(
|
|
lo.to(body.span),
|
|
ExprKind::Closure(Box::new(ast::Closure {
|
|
binder,
|
|
capture_clause,
|
|
constness,
|
|
coroutine_kind,
|
|
movability,
|
|
fn_decl,
|
|
body,
|
|
fn_decl_span: lo.to(decl_hi),
|
|
fn_arg_span,
|
|
})),
|
|
);
|
|
|
|
// Disable recovery for closure body
|
|
let spans =
|
|
ClosureSpans { whole_closure: closure.span, closing_pipe: decl_hi, body: body_span };
|
|
self.current_closure = Some(spans);
|
|
|
|
Ok(closure)
|
|
}
|
|
|
|
/// Parses an optional `move` prefix to a closure-like construct.
|
|
fn parse_capture_clause(&mut self) -> PResult<'a, CaptureBy> {
|
|
if self.eat_keyword(kw::Move) {
|
|
let move_kw_span = self.prev_token.span;
|
|
// Check for `move async` and recover
|
|
if self.check_keyword(kw::Async) {
|
|
let move_async_span = self.token.span.with_lo(self.prev_token.span.data().lo);
|
|
Err(self
|
|
.dcx()
|
|
.create_err(errors::AsyncMoveOrderIncorrect { span: move_async_span }))
|
|
} else {
|
|
Ok(CaptureBy::Value { move_kw: move_kw_span })
|
|
}
|
|
} else {
|
|
Ok(CaptureBy::Ref)
|
|
}
|
|
}
|
|
|
|
/// Parses the `|arg, arg|` header of a closure.
|
|
fn parse_fn_block_decl(&mut self) -> PResult<'a, (P<FnDecl>, Span)> {
|
|
let arg_start = self.token.span.lo();
|
|
|
|
let inputs = if self.eat(&token::OrOr) {
|
|
ThinVec::new()
|
|
} else {
|
|
self.expect(&token::BinOp(token::Or))?;
|
|
let args = self
|
|
.parse_seq_to_before_tokens(
|
|
&[&token::BinOp(token::Or), &token::OrOr],
|
|
SeqSep::trailing_allowed(token::Comma),
|
|
TokenExpectType::NoExpect,
|
|
|p| p.parse_fn_block_param(),
|
|
)?
|
|
.0;
|
|
self.expect_or()?;
|
|
args
|
|
};
|
|
let arg_span = self.prev_token.span.with_lo(arg_start);
|
|
let output =
|
|
self.parse_ret_ty(AllowPlus::Yes, RecoverQPath::Yes, RecoverReturnSign::Yes)?;
|
|
|
|
Ok((P(FnDecl { inputs, output }), arg_span))
|
|
}
|
|
|
|
/// Parses a parameter in a closure header (e.g., `|arg, arg|`).
|
|
fn parse_fn_block_param(&mut self) -> PResult<'a, Param> {
|
|
let lo = self.token.span;
|
|
let attrs = self.parse_outer_attributes()?;
|
|
self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| {
|
|
let pat = this.parse_pat_no_top_alt(Some(Expected::ParameterName), None)?;
|
|
let ty = if this.eat(&token::Colon) {
|
|
this.parse_ty()?
|
|
} else {
|
|
this.mk_ty(pat.span, TyKind::Infer)
|
|
};
|
|
|
|
Ok((
|
|
Param {
|
|
attrs,
|
|
ty,
|
|
pat,
|
|
span: lo.to(this.prev_token.span),
|
|
id: DUMMY_NODE_ID,
|
|
is_placeholder: false,
|
|
},
|
|
TrailingToken::MaybeComma,
|
|
))
|
|
})
|
|
}
|
|
|
|
/// Parses an `if` expression (`if` token already eaten).
|
|
fn parse_expr_if(&mut self) -> PResult<'a, P<Expr>> {
|
|
let lo = self.prev_token.span;
|
|
let cond = self.parse_expr_cond()?;
|
|
self.parse_if_after_cond(lo, cond)
|
|
}
|
|
|
|
fn parse_if_after_cond(&mut self, lo: Span, mut cond: P<Expr>) -> PResult<'a, P<Expr>> {
|
|
let cond_span = cond.span;
|
|
// Tries to interpret `cond` as either a missing expression if it's a block,
|
|
// or as an unfinished expression if it's a binop and the RHS is a block.
|
|
// We could probably add more recoveries here too...
|
|
let mut recover_block_from_condition = |this: &mut Self| {
|
|
let block = match &mut cond.kind {
|
|
ExprKind::Binary(Spanned { span: binop_span, .. }, _, right)
|
|
if let ExprKind::Block(_, None) = right.kind =>
|
|
{
|
|
self.sess.emit_err(errors::IfExpressionMissingThenBlock {
|
|
if_span: lo,
|
|
missing_then_block_sub:
|
|
errors::IfExpressionMissingThenBlockSub::UnfinishedCondition(
|
|
cond_span.shrink_to_lo().to(*binop_span),
|
|
),
|
|
let_else_sub: None,
|
|
});
|
|
std::mem::replace(right, this.mk_expr_err(binop_span.shrink_to_hi()))
|
|
}
|
|
ExprKind::Block(_, None) => {
|
|
self.sess.emit_err(errors::IfExpressionMissingCondition {
|
|
if_span: lo.shrink_to_hi(),
|
|
block_span: self.sess.source_map().start_point(cond_span),
|
|
});
|
|
std::mem::replace(&mut cond, this.mk_expr_err(cond_span.shrink_to_hi()))
|
|
}
|
|
_ => {
|
|
return None;
|
|
}
|
|
};
|
|
if let ExprKind::Block(block, _) = &block.kind {
|
|
Some(block.clone())
|
|
} else {
|
|
unreachable!()
|
|
}
|
|
};
|
|
// Parse then block
|
|
let thn = if self.token.is_keyword(kw::Else) {
|
|
if let Some(block) = recover_block_from_condition(self) {
|
|
block
|
|
} else {
|
|
let let_else_sub = matches!(cond.kind, ExprKind::Let(..))
|
|
.then(|| errors::IfExpressionLetSomeSub { if_span: lo.until(cond_span) });
|
|
|
|
self.sess.emit_err(errors::IfExpressionMissingThenBlock {
|
|
if_span: lo,
|
|
missing_then_block_sub: errors::IfExpressionMissingThenBlockSub::AddThenBlock(
|
|
cond_span.shrink_to_hi(),
|
|
),
|
|
let_else_sub,
|
|
});
|
|
self.mk_block_err(cond_span.shrink_to_hi())
|
|
}
|
|
} else {
|
|
let attrs = self.parse_outer_attributes()?; // For recovery.
|
|
let block = if self.check(&token::OpenDelim(Delimiter::Brace)) {
|
|
self.parse_block()?
|
|
} else {
|
|
if let Some(block) = recover_block_from_condition(self) {
|
|
block
|
|
} else {
|
|
self.error_on_extra_if(&cond)?;
|
|
// Parse block, which will always fail, but we can add a nice note to the error
|
|
self.parse_block().map_err(|mut err| {
|
|
if self.prev_token == token::Semi
|
|
&& self.token == token::AndAnd
|
|
&& let maybe_let = self.look_ahead(1, |t| t.clone())
|
|
&& maybe_let.is_keyword(kw::Let)
|
|
{
|
|
err.span_suggestion(
|
|
self.prev_token.span,
|
|
"consider removing this semicolon to parse the `let` as part of the same chain",
|
|
"",
|
|
Applicability::MachineApplicable,
|
|
).span_note(
|
|
self.token.span.to(maybe_let.span),
|
|
"you likely meant to continue parsing the let-chain starting here",
|
|
);
|
|
} else {
|
|
err.span_note(
|
|
cond_span,
|
|
"the `if` expression is missing a block after this condition",
|
|
);
|
|
}
|
|
err
|
|
})?
|
|
}
|
|
};
|
|
self.error_on_if_block_attrs(lo, false, block.span, attrs);
|
|
block
|
|
};
|
|
let els = if self.eat_keyword(kw::Else) { Some(self.parse_expr_else()?) } else { None };
|
|
Ok(self.mk_expr(lo.to(self.prev_token.span), ExprKind::If(cond, thn, els)))
|
|
}
|
|
|
|
/// Parses the condition of a `if` or `while` expression.
|
|
fn parse_expr_cond(&mut self) -> PResult<'a, P<Expr>> {
|
|
let mut cond =
|
|
self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL | Restrictions::ALLOW_LET, None)?;
|
|
|
|
CondChecker::new(self).visit_expr(&mut cond);
|
|
|
|
if let ExprKind::Let(_, _, _, None) = cond.kind {
|
|
// Remove the last feature gating of a `let` expression since it's stable.
|
|
self.sess.gated_spans.ungate_last(sym::let_chains, cond.span);
|
|
}
|
|
|
|
Ok(cond)
|
|
}
|
|
|
|
/// Parses a `let $pat = $expr` pseudo-expression.
|
|
fn parse_expr_let(&mut self, restrictions: Restrictions) -> PResult<'a, P<Expr>> {
|
|
let is_recovered = if !restrictions.contains(Restrictions::ALLOW_LET) {
|
|
let err = errors::ExpectedExpressionFoundLet {
|
|
span: self.token.span,
|
|
reason: ForbiddenLetReason::OtherForbidden,
|
|
missing_let: None,
|
|
comparison: None,
|
|
};
|
|
if self.prev_token.kind == token::BinOp(token::Or) {
|
|
// This was part of a closure, the that part of the parser recover.
|
|
return Err(self.dcx().create_err(err));
|
|
} else {
|
|
Some(self.sess.emit_err(err))
|
|
}
|
|
} else {
|
|
None
|
|
};
|
|
self.bump(); // Eat `let` token
|
|
let lo = self.prev_token.span;
|
|
let pat = self.parse_pat_allow_top_alt(
|
|
None,
|
|
RecoverComma::Yes,
|
|
RecoverColon::Yes,
|
|
CommaRecoveryMode::LikelyTuple,
|
|
)?;
|
|
if self.token == token::EqEq {
|
|
self.sess.emit_err(errors::ExpectedEqForLetExpr {
|
|
span: self.token.span,
|
|
sugg_span: self.token.span,
|
|
});
|
|
self.bump();
|
|
} else {
|
|
self.expect(&token::Eq)?;
|
|
}
|
|
let expr = self.parse_expr_assoc_with(1 + prec_let_scrutinee_needs_par(), None.into())?;
|
|
let span = lo.to(expr.span);
|
|
Ok(self.mk_expr(span, ExprKind::Let(pat, expr, span, is_recovered)))
|
|
}
|
|
|
|
/// Parses an `else { ... }` expression (`else` token already eaten).
|
|
fn parse_expr_else(&mut self) -> PResult<'a, P<Expr>> {
|
|
let else_span = self.prev_token.span; // `else`
|
|
let attrs = self.parse_outer_attributes()?; // For recovery.
|
|
let expr = if self.eat_keyword(kw::If) {
|
|
ensure_sufficient_stack(|| self.parse_expr_if())?
|
|
} else if self.check(&TokenKind::OpenDelim(Delimiter::Brace)) {
|
|
self.parse_simple_block()?
|
|
} else {
|
|
let snapshot = self.create_snapshot_for_diagnostic();
|
|
let first_tok = super::token_descr(&self.token);
|
|
let first_tok_span = self.token.span;
|
|
match self.parse_expr() {
|
|
Ok(cond)
|
|
// If it's not a free-standing expression, and is followed by a block,
|
|
// then it's very likely the condition to an `else if`.
|
|
if self.check(&TokenKind::OpenDelim(Delimiter::Brace))
|
|
&& classify::expr_requires_semi_to_be_stmt(&cond) =>
|
|
{
|
|
self.sess.emit_err(errors::ExpectedElseBlock {
|
|
first_tok_span,
|
|
first_tok,
|
|
else_span,
|
|
condition_start: cond.span.shrink_to_lo(),
|
|
});
|
|
self.parse_if_after_cond(cond.span.shrink_to_lo(), cond)?
|
|
}
|
|
Err(e) => {
|
|
e.cancel();
|
|
self.restore_snapshot(snapshot);
|
|
self.parse_simple_block()?
|
|
},
|
|
Ok(_) => {
|
|
self.restore_snapshot(snapshot);
|
|
self.parse_simple_block()?
|
|
},
|
|
}
|
|
};
|
|
self.error_on_if_block_attrs(else_span, true, expr.span, attrs);
|
|
Ok(expr)
|
|
}
|
|
|
|
fn error_on_if_block_attrs(
|
|
&self,
|
|
ctx_span: Span,
|
|
is_ctx_else: bool,
|
|
branch_span: Span,
|
|
attrs: AttrWrapper,
|
|
) {
|
|
if attrs.is_empty() {
|
|
return;
|
|
}
|
|
|
|
let attrs: &[ast::Attribute] = &attrs.take_for_recovery(self.sess);
|
|
let (attributes, last) = match attrs {
|
|
[] => return,
|
|
[x0 @ xn] | [x0, .., xn] => (x0.span.to(xn.span), xn.span),
|
|
};
|
|
let ctx = if is_ctx_else { "else" } else { "if" };
|
|
self.sess.emit_err(errors::OuterAttributeNotAllowedOnIfElse {
|
|
last,
|
|
branch_span,
|
|
ctx_span,
|
|
ctx: ctx.to_string(),
|
|
attributes,
|
|
});
|
|
}
|
|
|
|
fn error_on_extra_if(&mut self, cond: &P<Expr>) -> PResult<'a, ()> {
|
|
if let ExprKind::Binary(Spanned { span: binop_span, node: binop }, _, right) = &cond.kind
|
|
&& let BinOpKind::And = binop
|
|
&& let ExprKind::If(cond, ..) = &right.kind
|
|
{
|
|
Err(self.sess.create_err(errors::UnexpectedIfWithIf(
|
|
binop_span.shrink_to_hi().to(cond.span.shrink_to_lo()),
|
|
)))
|
|
} else {
|
|
Ok(())
|
|
}
|
|
}
|
|
|
|
fn parse_for_head(&mut self) -> PResult<'a, (P<Pat>, P<Expr>)> {
|
|
let begin_paren = if self.token.kind == token::OpenDelim(Delimiter::Parenthesis) {
|
|
// Record whether we are about to parse `for (`.
|
|
// This is used below for recovery in case of `for ( $stuff ) $block`
|
|
// in which case we will suggest `for $stuff $block`.
|
|
let start_span = self.token.span;
|
|
let left = self.prev_token.span.between(self.look_ahead(1, |t| t.span));
|
|
Some((start_span, left))
|
|
} else {
|
|
None
|
|
};
|
|
// Try to parse the pattern `for ($PAT) in $EXPR`.
|
|
let pat = match (
|
|
self.parse_pat_allow_top_alt(
|
|
None,
|
|
RecoverComma::Yes,
|
|
RecoverColon::Yes,
|
|
CommaRecoveryMode::LikelyTuple,
|
|
),
|
|
begin_paren,
|
|
) {
|
|
(Ok(pat), _) => pat, // Happy path.
|
|
(Err(err), Some((start_span, left))) if self.eat_keyword(kw::In) => {
|
|
// We know for sure we have seen `for ($SOMETHING in`. In the happy path this would
|
|
// happen right before the return of this method.
|
|
let expr = match self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None) {
|
|
Ok(expr) => expr,
|
|
Err(expr_err) => {
|
|
// We don't know what followed the `in`, so cancel and bubble up the
|
|
// original error.
|
|
expr_err.cancel();
|
|
return Err(err);
|
|
}
|
|
};
|
|
return if self.token.kind == token::CloseDelim(Delimiter::Parenthesis) {
|
|
// We know for sure we have seen `for ($SOMETHING in $EXPR)`, so we recover the
|
|
// parser state and emit a targetted suggestion.
|
|
let span = vec![start_span, self.token.span];
|
|
let right = self.prev_token.span.between(self.look_ahead(1, |t| t.span));
|
|
self.bump(); // )
|
|
err.cancel();
|
|
self.sess.emit_err(errors::ParenthesesInForHead {
|
|
span,
|
|
// With e.g. `for (x) in y)` this would replace `(x) in y)`
|
|
// with `x) in y)` which is syntactically invalid.
|
|
// However, this is prevented before we get here.
|
|
sugg: errors::ParenthesesInForHeadSugg { left, right },
|
|
});
|
|
Ok((self.mk_pat(start_span.to(right), ast::PatKind::Wild), expr))
|
|
} else {
|
|
Err(err) // Some other error, bubble up.
|
|
};
|
|
}
|
|
(Err(err), _) => return Err(err), // Some other error, bubble up.
|
|
};
|
|
if !self.eat_keyword(kw::In) {
|
|
self.error_missing_in_for_loop();
|
|
}
|
|
self.check_for_for_in_in_typo(self.prev_token.span);
|
|
let expr = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?;
|
|
Ok((pat, expr))
|
|
}
|
|
|
|
/// Parses `for await? <src_pat> in <src_expr> <src_loop_block>` (`for` token already eaten).
|
|
fn parse_expr_for(&mut self, opt_label: Option<Label>, lo: Span) -> PResult<'a, P<Expr>> {
|
|
let is_await =
|
|
self.token.uninterpolated_span().at_least_rust_2018() && self.eat_keyword(kw::Await);
|
|
|
|
if is_await {
|
|
self.sess.gated_spans.gate(sym::async_for_loop, self.prev_token.span);
|
|
}
|
|
|
|
let kind = if is_await { ForLoopKind::ForAwait } else { ForLoopKind::For };
|
|
|
|
let (pat, expr) = self.parse_for_head()?;
|
|
// Recover from missing expression in `for` loop
|
|
if matches!(expr.kind, ExprKind::Block(..))
|
|
&& !matches!(self.token.kind, token::OpenDelim(Delimiter::Brace))
|
|
&& self.may_recover()
|
|
{
|
|
self.sess
|
|
.emit_err(errors::MissingExpressionInForLoop { span: expr.span.shrink_to_lo() });
|
|
let err_expr = self.mk_expr(expr.span, ExprKind::Err);
|
|
let block = self.mk_block(thin_vec![], BlockCheckMode::Default, self.prev_token.span);
|
|
return Ok(self.mk_expr(
|
|
lo.to(self.prev_token.span),
|
|
ExprKind::ForLoop { pat, iter: err_expr, body: block, label: opt_label, kind },
|
|
));
|
|
}
|
|
|
|
let (attrs, loop_block) = self.parse_inner_attrs_and_block()?;
|
|
|
|
let kind = ExprKind::ForLoop { pat, iter: expr, body: loop_block, label: opt_label, kind };
|
|
|
|
self.recover_loop_else("for", lo)?;
|
|
|
|
Ok(self.mk_expr_with_attrs(lo.to(self.prev_token.span), kind, attrs))
|
|
}
|
|
|
|
/// Recovers from an `else` clause after a loop (`for...else`, `while...else`)
|
|
fn recover_loop_else(&mut self, loop_kind: &'static str, loop_kw: Span) -> PResult<'a, ()> {
|
|
if self.token.is_keyword(kw::Else) && self.may_recover() {
|
|
let else_span = self.token.span;
|
|
self.bump();
|
|
let else_clause = self.parse_expr_else()?;
|
|
self.sess.emit_err(errors::LoopElseNotSupported {
|
|
span: else_span.to(else_clause.span),
|
|
loop_kind,
|
|
loop_kw,
|
|
});
|
|
}
|
|
Ok(())
|
|
}
|
|
|
|
fn error_missing_in_for_loop(&mut self) {
|
|
let (span, sub): (_, fn(_) -> _) = if self.token.is_ident_named(sym::of) {
|
|
// Possibly using JS syntax (#75311).
|
|
let span = self.token.span;
|
|
self.bump();
|
|
(span, errors::MissingInInForLoopSub::InNotOf)
|
|
} else {
|
|
(self.prev_token.span.between(self.token.span), errors::MissingInInForLoopSub::AddIn)
|
|
};
|
|
|
|
self.sess.emit_err(errors::MissingInInForLoop { span, sub: sub(span) });
|
|
}
|
|
|
|
/// Parses a `while` or `while let` expression (`while` token already eaten).
|
|
fn parse_expr_while(&mut self, opt_label: Option<Label>, lo: Span) -> PResult<'a, P<Expr>> {
|
|
let cond = self.parse_expr_cond().map_err(|mut err| {
|
|
err.span_label(lo, "while parsing the condition of this `while` expression");
|
|
err
|
|
})?;
|
|
let (attrs, body) = self.parse_inner_attrs_and_block().map_err(|mut err| {
|
|
err.span_label(lo, "while parsing the body of this `while` expression");
|
|
err.span_label(cond.span, "this `while` condition successfully parsed");
|
|
err
|
|
})?;
|
|
|
|
self.recover_loop_else("while", lo)?;
|
|
|
|
Ok(self.mk_expr_with_attrs(
|
|
lo.to(self.prev_token.span),
|
|
ExprKind::While(cond, body, opt_label),
|
|
attrs,
|
|
))
|
|
}
|
|
|
|
/// Parses `loop { ... }` (`loop` token already eaten).
|
|
fn parse_expr_loop(&mut self, opt_label: Option<Label>, lo: Span) -> PResult<'a, P<Expr>> {
|
|
let loop_span = self.prev_token.span;
|
|
let (attrs, body) = self.parse_inner_attrs_and_block()?;
|
|
self.recover_loop_else("loop", lo)?;
|
|
Ok(self.mk_expr_with_attrs(
|
|
lo.to(self.prev_token.span),
|
|
ExprKind::Loop(body, opt_label, loop_span),
|
|
attrs,
|
|
))
|
|
}
|
|
|
|
pub(crate) fn eat_label(&mut self) -> Option<Label> {
|
|
self.token.lifetime().map(|ident| {
|
|
self.bump();
|
|
Label { ident }
|
|
})
|
|
}
|
|
|
|
/// Parses a `match ... { ... }` expression (`match` token already eaten).
|
|
fn parse_expr_match(&mut self) -> PResult<'a, P<Expr>> {
|
|
let match_span = self.prev_token.span;
|
|
let lo = self.prev_token.span;
|
|
let scrutinee = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?;
|
|
if let Err(mut e) = self.expect(&token::OpenDelim(Delimiter::Brace)) {
|
|
if self.token == token::Semi {
|
|
e.span_suggestion_short(
|
|
match_span,
|
|
"try removing this `match`",
|
|
"",
|
|
Applicability::MaybeIncorrect, // speculative
|
|
);
|
|
}
|
|
if self.maybe_recover_unexpected_block_label() {
|
|
e.cancel();
|
|
self.bump();
|
|
} else {
|
|
return Err(e);
|
|
}
|
|
}
|
|
let attrs = self.parse_inner_attributes()?;
|
|
|
|
let mut arms = ThinVec::new();
|
|
while self.token != token::CloseDelim(Delimiter::Brace) {
|
|
match self.parse_arm() {
|
|
Ok(arm) => arms.push(arm),
|
|
Err(mut e) => {
|
|
// Recover by skipping to the end of the block.
|
|
e.emit();
|
|
self.recover_stmt();
|
|
let span = lo.to(self.token.span);
|
|
if self.token == token::CloseDelim(Delimiter::Brace) {
|
|
self.bump();
|
|
}
|
|
return Ok(self.mk_expr_with_attrs(
|
|
span,
|
|
ExprKind::Match(scrutinee, arms),
|
|
attrs,
|
|
));
|
|
}
|
|
}
|
|
}
|
|
let hi = self.token.span;
|
|
self.bump();
|
|
Ok(self.mk_expr_with_attrs(lo.to(hi), ExprKind::Match(scrutinee, arms), attrs))
|
|
}
|
|
|
|
/// Attempt to recover from match arm body with statements and no surrounding braces.
|
|
fn parse_arm_body_missing_braces(
|
|
&mut self,
|
|
first_expr: &P<Expr>,
|
|
arrow_span: Span,
|
|
) -> Option<P<Expr>> {
|
|
if self.token.kind != token::Semi {
|
|
return None;
|
|
}
|
|
let start_snapshot = self.create_snapshot_for_diagnostic();
|
|
let semi_sp = self.token.span;
|
|
self.bump(); // `;`
|
|
let mut stmts =
|
|
vec![self.mk_stmt(first_expr.span, ast::StmtKind::Expr(first_expr.clone()))];
|
|
let err = |this: &Parser<'_>, stmts: Vec<ast::Stmt>| {
|
|
let span = stmts[0].span.to(stmts[stmts.len() - 1].span);
|
|
|
|
this.sess.emit_err(errors::MatchArmBodyWithoutBraces {
|
|
statements: span,
|
|
arrow: arrow_span,
|
|
num_statements: stmts.len(),
|
|
sub: if stmts.len() > 1 {
|
|
errors::MatchArmBodyWithoutBracesSugg::AddBraces {
|
|
left: span.shrink_to_lo(),
|
|
right: span.shrink_to_hi(),
|
|
}
|
|
} else {
|
|
errors::MatchArmBodyWithoutBracesSugg::UseComma { semicolon: semi_sp }
|
|
},
|
|
});
|
|
this.mk_expr_err(span)
|
|
};
|
|
// We might have either a `,` -> `;` typo, or a block without braces. We need
|
|
// a more subtle parsing strategy.
|
|
loop {
|
|
if self.token.kind == token::CloseDelim(Delimiter::Brace) {
|
|
// We have reached the closing brace of the `match` expression.
|
|
return Some(err(self, stmts));
|
|
}
|
|
if self.token.kind == token::Comma {
|
|
self.restore_snapshot(start_snapshot);
|
|
return None;
|
|
}
|
|
let pre_pat_snapshot = self.create_snapshot_for_diagnostic();
|
|
match self.parse_pat_no_top_alt(None, None) {
|
|
Ok(_pat) => {
|
|
if self.token.kind == token::FatArrow {
|
|
// Reached arm end.
|
|
self.restore_snapshot(pre_pat_snapshot);
|
|
return Some(err(self, stmts));
|
|
}
|
|
}
|
|
Err(err) => {
|
|
err.cancel();
|
|
}
|
|
}
|
|
|
|
self.restore_snapshot(pre_pat_snapshot);
|
|
match self.parse_stmt_without_recovery(true, ForceCollect::No) {
|
|
// Consume statements for as long as possible.
|
|
Ok(Some(stmt)) => {
|
|
stmts.push(stmt);
|
|
}
|
|
Ok(None) => {
|
|
self.restore_snapshot(start_snapshot);
|
|
break;
|
|
}
|
|
// We couldn't parse either yet another statement missing it's
|
|
// enclosing block nor the next arm's pattern or closing brace.
|
|
Err(stmt_err) => {
|
|
stmt_err.cancel();
|
|
self.restore_snapshot(start_snapshot);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
None
|
|
}
|
|
|
|
pub(super) fn parse_arm(&mut self) -> PResult<'a, Arm> {
|
|
let attrs = self.parse_outer_attributes()?;
|
|
self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| {
|
|
let lo = this.token.span;
|
|
let (pat, guard) = this.parse_match_arm_pat_and_guard()?;
|
|
|
|
let span_before_body = this.prev_token.span;
|
|
let arm_body;
|
|
let is_fat_arrow = this.check(&token::FatArrow);
|
|
let is_almost_fat_arrow = TokenKind::FatArrow
|
|
.similar_tokens()
|
|
.is_some_and(|similar_tokens| similar_tokens.contains(&this.token.kind));
|
|
let mut result = if !is_fat_arrow && !is_almost_fat_arrow {
|
|
// A pattern without a body, allowed for never patterns.
|
|
arm_body = None;
|
|
this.expect_one_of(&[token::Comma], &[token::CloseDelim(Delimiter::Brace)]).map(
|
|
|x| {
|
|
// Don't gate twice
|
|
if !pat.contains_never_pattern() {
|
|
this.sess.gated_spans.gate(sym::never_patterns, pat.span);
|
|
}
|
|
x
|
|
},
|
|
)
|
|
} else {
|
|
if let Err(mut err) = this.expect(&token::FatArrow) {
|
|
// We might have a `=>` -> `=` or `->` typo (issue #89396).
|
|
if is_almost_fat_arrow {
|
|
err.span_suggestion(
|
|
this.token.span,
|
|
"use a fat arrow to start a match arm",
|
|
"=>",
|
|
Applicability::MachineApplicable,
|
|
);
|
|
if matches!(
|
|
(&this.prev_token.kind, &this.token.kind),
|
|
(token::DotDotEq, token::Gt)
|
|
) {
|
|
// `error_inclusive_range_match_arrow` handles cases like `0..=> {}`,
|
|
// so we suppress the error here
|
|
err.delay_as_bug();
|
|
} else {
|
|
err.emit();
|
|
}
|
|
this.bump();
|
|
} else {
|
|
return Err(err);
|
|
}
|
|
}
|
|
let arrow_span = this.prev_token.span;
|
|
let arm_start_span = this.token.span;
|
|
|
|
let expr =
|
|
this.parse_expr_res(Restrictions::STMT_EXPR, None).map_err(|mut err| {
|
|
err.span_label(arrow_span, "while parsing the `match` arm starting here");
|
|
err
|
|
})?;
|
|
|
|
let require_comma = classify::expr_requires_semi_to_be_stmt(&expr)
|
|
&& this.token != token::CloseDelim(Delimiter::Brace);
|
|
|
|
if !require_comma {
|
|
arm_body = Some(expr);
|
|
this.eat(&token::Comma);
|
|
Ok(false)
|
|
} else if let Some(body) = this.parse_arm_body_missing_braces(&expr, arrow_span) {
|
|
arm_body = Some(body);
|
|
Ok(true)
|
|
} else {
|
|
let expr_span = expr.span;
|
|
arm_body = Some(expr);
|
|
this.expect_one_of(&[token::Comma], &[token::CloseDelim(Delimiter::Brace)])
|
|
.map_err(|mut err| {
|
|
if this.token == token::FatArrow {
|
|
let sm = this.sess.source_map();
|
|
if let Ok(expr_lines) = sm.span_to_lines(expr_span)
|
|
&& let Ok(arm_start_lines) = sm.span_to_lines(arm_start_span)
|
|
&& arm_start_lines.lines[0].end_col
|
|
== expr_lines.lines[0].end_col
|
|
&& expr_lines.lines.len() == 2
|
|
{
|
|
// We check whether there's any trailing code in the parse span,
|
|
// if there isn't, we very likely have the following:
|
|
//
|
|
// X | &Y => "y"
|
|
// | -- - missing comma
|
|
// | |
|
|
// | arrow_span
|
|
// X | &X => "x"
|
|
// | - ^^ self.token.span
|
|
// | |
|
|
// | parsed until here as `"y" & X`
|
|
err.span_suggestion_short(
|
|
arm_start_span.shrink_to_hi(),
|
|
"missing a comma here to end this `match` arm",
|
|
",",
|
|
Applicability::MachineApplicable,
|
|
);
|
|
}
|
|
} else {
|
|
err.span_label(
|
|
arrow_span,
|
|
"while parsing the `match` arm starting here",
|
|
);
|
|
}
|
|
err
|
|
})
|
|
}
|
|
};
|
|
|
|
let hi_span = arm_body.as_ref().map_or(span_before_body, |body| body.span);
|
|
let arm_span = lo.to(hi_span);
|
|
|
|
// We want to recover:
|
|
// X | Some(_) => foo()
|
|
// | - missing comma
|
|
// X | None => "x"
|
|
// | ^^^^ self.token.span
|
|
// as well as:
|
|
// X | Some(!)
|
|
// | - missing comma
|
|
// X | None => "x"
|
|
// | ^^^^ self.token.span
|
|
// But we musn't recover
|
|
// X | pat[0] => {}
|
|
// | ^ self.token.span
|
|
let recover_missing_comma = arm_body.is_some() || pat.could_be_never_pattern();
|
|
if recover_missing_comma {
|
|
result = result.or_else(|err| {
|
|
// FIXME(compiler-errors): We could also recover `; PAT =>` here
|
|
|
|
// Try to parse a following `PAT =>`, if successful
|
|
// then we should recover.
|
|
let mut snapshot = this.create_snapshot_for_diagnostic();
|
|
let pattern_follows = snapshot
|
|
.parse_pat_allow_top_alt(
|
|
None,
|
|
RecoverComma::Yes,
|
|
RecoverColon::Yes,
|
|
CommaRecoveryMode::EitherTupleOrPipe,
|
|
)
|
|
.map_err(|err| err.cancel())
|
|
.is_ok();
|
|
if pattern_follows && snapshot.check(&TokenKind::FatArrow) {
|
|
err.cancel();
|
|
this.sess.emit_err(errors::MissingCommaAfterMatchArm {
|
|
span: arm_span.shrink_to_hi(),
|
|
});
|
|
return Ok(true);
|
|
}
|
|
Err(err)
|
|
});
|
|
}
|
|
result?;
|
|
|
|
Ok((
|
|
ast::Arm {
|
|
attrs,
|
|
pat,
|
|
guard,
|
|
body: arm_body,
|
|
span: arm_span,
|
|
id: DUMMY_NODE_ID,
|
|
is_placeholder: false,
|
|
},
|
|
TrailingToken::None,
|
|
))
|
|
})
|
|
}
|
|
|
|
fn parse_match_arm_guard(&mut self) -> PResult<'a, Option<P<Expr>>> {
|
|
// Used to check the `let_chains` and `if_let_guard` features mostly by scanning
|
|
// `&&` tokens.
|
|
fn check_let_expr(expr: &Expr) -> (bool, bool) {
|
|
match &expr.kind {
|
|
ExprKind::Binary(BinOp { node: BinOpKind::And, .. }, lhs, rhs) => {
|
|
let lhs_rslt = check_let_expr(lhs);
|
|
let rhs_rslt = check_let_expr(rhs);
|
|
(lhs_rslt.0 || rhs_rslt.0, false)
|
|
}
|
|
ExprKind::Let(..) => (true, true),
|
|
_ => (false, true),
|
|
}
|
|
}
|
|
if !self.eat_keyword(kw::If) {
|
|
// No match arm guard present.
|
|
return Ok(None);
|
|
}
|
|
|
|
let if_span = self.prev_token.span;
|
|
let mut cond = self.parse_match_guard_condition()?;
|
|
|
|
CondChecker::new(self).visit_expr(&mut cond);
|
|
|
|
let (has_let_expr, does_not_have_bin_op) = check_let_expr(&cond);
|
|
if has_let_expr {
|
|
if does_not_have_bin_op {
|
|
// Remove the last feature gating of a `let` expression since it's stable.
|
|
self.sess.gated_spans.ungate_last(sym::let_chains, cond.span);
|
|
}
|
|
let span = if_span.to(cond.span);
|
|
self.sess.gated_spans.gate(sym::if_let_guard, span);
|
|
}
|
|
Ok(Some(cond))
|
|
}
|
|
|
|
fn parse_match_arm_pat_and_guard(&mut self) -> PResult<'a, (P<Pat>, Option<P<Expr>>)> {
|
|
if self.token.kind == token::OpenDelim(Delimiter::Parenthesis) {
|
|
// Detect and recover from `($pat if $cond) => $arm`.
|
|
let left = self.token.span;
|
|
match self.parse_pat_allow_top_alt(
|
|
None,
|
|
RecoverComma::Yes,
|
|
RecoverColon::Yes,
|
|
CommaRecoveryMode::EitherTupleOrPipe,
|
|
) {
|
|
Ok(pat) => Ok((pat, self.parse_match_arm_guard()?)),
|
|
Err(err)
|
|
if let prev_sp = self.prev_token.span
|
|
&& let true = self.eat_keyword(kw::If) =>
|
|
{
|
|
// We know for certain we've found `($pat if` so far.
|
|
let mut cond = match self.parse_match_guard_condition() {
|
|
Ok(cond) => cond,
|
|
Err(cond_err) => {
|
|
cond_err.cancel();
|
|
return Err(err);
|
|
}
|
|
};
|
|
err.cancel();
|
|
CondChecker::new(self).visit_expr(&mut cond);
|
|
self.eat_to_tokens(&[&token::CloseDelim(Delimiter::Parenthesis)]);
|
|
self.expect(&token::CloseDelim(Delimiter::Parenthesis))?;
|
|
let right = self.prev_token.span;
|
|
self.sess.emit_err(errors::ParenthesesInMatchPat {
|
|
span: vec![left, right],
|
|
sugg: errors::ParenthesesInMatchPatSugg { left, right },
|
|
});
|
|
Ok((self.mk_pat(left.to(prev_sp), ast::PatKind::Wild), Some(cond)))
|
|
}
|
|
Err(err) => Err(err),
|
|
}
|
|
} else {
|
|
// Regular parser flow:
|
|
let pat = self.parse_pat_allow_top_alt(
|
|
None,
|
|
RecoverComma::Yes,
|
|
RecoverColon::Yes,
|
|
CommaRecoveryMode::EitherTupleOrPipe,
|
|
)?;
|
|
Ok((pat, self.parse_match_arm_guard()?))
|
|
}
|
|
}
|
|
|
|
fn parse_match_guard_condition(&mut self) -> PResult<'a, P<Expr>> {
|
|
self.parse_expr_res(Restrictions::ALLOW_LET | Restrictions::IN_IF_GUARD, None).map_err(
|
|
|mut err| {
|
|
if self.prev_token == token::OpenDelim(Delimiter::Brace) {
|
|
let sugg_sp = self.prev_token.span.shrink_to_lo();
|
|
// Consume everything within the braces, let's avoid further parse
|
|
// errors.
|
|
self.recover_stmt_(SemiColonMode::Ignore, BlockMode::Ignore);
|
|
let msg = "you might have meant to start a match arm after the match guard";
|
|
if self.eat(&token::CloseDelim(Delimiter::Brace)) {
|
|
let applicability = if self.token.kind != token::FatArrow {
|
|
// We have high confidence that we indeed didn't have a struct
|
|
// literal in the match guard, but rather we had some operation
|
|
// that ended in a path, immediately followed by a block that was
|
|
// meant to be the match arm.
|
|
Applicability::MachineApplicable
|
|
} else {
|
|
Applicability::MaybeIncorrect
|
|
};
|
|
err.span_suggestion_verbose(sugg_sp, msg, "=> ".to_string(), applicability);
|
|
}
|
|
}
|
|
err
|
|
},
|
|
)
|
|
}
|
|
|
|
pub(crate) fn is_builtin(&self) -> bool {
|
|
self.token.is_keyword(kw::Builtin) && self.look_ahead(1, |t| *t == token::Pound)
|
|
}
|
|
|
|
/// Parses a `try {...}` expression (`try` token already eaten).
|
|
fn parse_try_block(&mut self, span_lo: Span) -> PResult<'a, P<Expr>> {
|
|
let (attrs, body) = self.parse_inner_attrs_and_block()?;
|
|
if self.eat_keyword(kw::Catch) {
|
|
Err(self.dcx().create_err(errors::CatchAfterTry { span: self.prev_token.span }))
|
|
} else {
|
|
let span = span_lo.to(body.span);
|
|
self.sess.gated_spans.gate(sym::try_blocks, span);
|
|
Ok(self.mk_expr_with_attrs(span, ExprKind::TryBlock(body), attrs))
|
|
}
|
|
}
|
|
|
|
fn is_do_catch_block(&self) -> bool {
|
|
self.token.is_keyword(kw::Do)
|
|
&& self.is_keyword_ahead(1, &[kw::Catch])
|
|
&& self
|
|
.look_ahead(2, |t| *t == token::OpenDelim(Delimiter::Brace) || t.is_whole_block())
|
|
&& !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL)
|
|
}
|
|
|
|
fn is_do_yeet(&self) -> bool {
|
|
self.token.is_keyword(kw::Do) && self.is_keyword_ahead(1, &[kw::Yeet])
|
|
}
|
|
|
|
fn is_try_block(&self) -> bool {
|
|
self.token.is_keyword(kw::Try)
|
|
&& self
|
|
.look_ahead(1, |t| *t == token::OpenDelim(Delimiter::Brace) || t.is_whole_block())
|
|
&& self.token.uninterpolated_span().at_least_rust_2018()
|
|
}
|
|
|
|
/// Parses an `async move? {...}` or `gen move? {...}` expression.
|
|
fn parse_gen_block(&mut self) -> PResult<'a, P<Expr>> {
|
|
let lo = self.token.span;
|
|
let kind = if self.eat_keyword(kw::Async) {
|
|
if self.eat_keyword(kw::Gen) { GenBlockKind::AsyncGen } else { GenBlockKind::Async }
|
|
} else {
|
|
assert!(self.eat_keyword(kw::Gen));
|
|
GenBlockKind::Gen
|
|
};
|
|
match kind {
|
|
GenBlockKind::Async => {
|
|
// `async` blocks are stable
|
|
}
|
|
GenBlockKind::Gen | GenBlockKind::AsyncGen => {
|
|
self.sess.gated_spans.gate(sym::gen_blocks, lo.to(self.prev_token.span));
|
|
}
|
|
}
|
|
let capture_clause = self.parse_capture_clause()?;
|
|
let (attrs, body) = self.parse_inner_attrs_and_block()?;
|
|
let kind = ExprKind::Gen(capture_clause, body, kind);
|
|
Ok(self.mk_expr_with_attrs(lo.to(self.prev_token.span), kind, attrs))
|
|
}
|
|
|
|
fn is_gen_block(&self, kw: Symbol, lookahead: usize) -> bool {
|
|
self.is_keyword_ahead(lookahead, &[kw])
|
|
&& ((
|
|
// `async move {`
|
|
self.is_keyword_ahead(lookahead + 1, &[kw::Move])
|
|
&& self.look_ahead(lookahead + 2, |t| {
|
|
*t == token::OpenDelim(Delimiter::Brace) || t.is_whole_block()
|
|
})
|
|
) || (
|
|
// `async {`
|
|
self.look_ahead(lookahead + 1, |t| {
|
|
*t == token::OpenDelim(Delimiter::Brace) || t.is_whole_block()
|
|
})
|
|
))
|
|
}
|
|
|
|
pub(super) fn is_async_gen_block(&self) -> bool {
|
|
self.token.is_keyword(kw::Async) && self.is_gen_block(kw::Gen, 1)
|
|
}
|
|
|
|
fn is_certainly_not_a_block(&self) -> bool {
|
|
self.look_ahead(1, |t| t.is_ident())
|
|
&& (
|
|
// `{ ident, ` cannot start a block.
|
|
self.look_ahead(2, |t| t == &token::Comma)
|
|
|| self.look_ahead(2, |t| t == &token::Colon)
|
|
&& (
|
|
// `{ ident: token, ` cannot start a block.
|
|
self.look_ahead(4, |t| t == &token::Comma)
|
|
// `{ ident: ` cannot start a block unless it's a type ascription
|
|
// `ident: Type`.
|
|
|| self.look_ahead(3, |t| !t.can_begin_type())
|
|
)
|
|
)
|
|
}
|
|
|
|
fn maybe_parse_struct_expr(
|
|
&mut self,
|
|
qself: &Option<P<ast::QSelf>>,
|
|
path: &ast::Path,
|
|
) -> Option<PResult<'a, P<Expr>>> {
|
|
let struct_allowed = !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL);
|
|
if struct_allowed || self.is_certainly_not_a_block() {
|
|
if let Err(err) = self.expect(&token::OpenDelim(Delimiter::Brace)) {
|
|
return Some(Err(err));
|
|
}
|
|
let expr = self.parse_expr_struct(qself.clone(), path.clone(), true);
|
|
if let (Ok(expr), false) = (&expr, struct_allowed) {
|
|
// This is a struct literal, but we don't can't accept them here.
|
|
self.sess.emit_err(errors::StructLiteralNotAllowedHere {
|
|
span: expr.span,
|
|
sub: errors::StructLiteralNotAllowedHereSugg {
|
|
left: path.span.shrink_to_lo(),
|
|
right: expr.span.shrink_to_hi(),
|
|
},
|
|
});
|
|
}
|
|
return Some(expr);
|
|
}
|
|
None
|
|
}
|
|
|
|
pub(super) fn parse_struct_fields(
|
|
&mut self,
|
|
pth: ast::Path,
|
|
recover: bool,
|
|
close_delim: Delimiter,
|
|
) -> PResult<'a, (ThinVec<ExprField>, ast::StructRest, bool)> {
|
|
let mut fields = ThinVec::new();
|
|
let mut base = ast::StructRest::None;
|
|
let mut recover_async = false;
|
|
let in_if_guard = self.restrictions.contains(Restrictions::IN_IF_GUARD);
|
|
|
|
let mut async_block_err = |e: &mut Diagnostic, span: Span| {
|
|
recover_async = true;
|
|
errors::AsyncBlockIn2015 { span }.add_to_diagnostic(e);
|
|
errors::HelpUseLatestEdition::new().add_to_diagnostic(e);
|
|
};
|
|
|
|
while self.token != token::CloseDelim(close_delim) {
|
|
if self.eat(&token::DotDot) || self.recover_struct_field_dots(close_delim) {
|
|
let exp_span = self.prev_token.span;
|
|
// We permit `.. }` on the left-hand side of a destructuring assignment.
|
|
if self.check(&token::CloseDelim(close_delim)) {
|
|
base = ast::StructRest::Rest(self.prev_token.span.shrink_to_hi());
|
|
break;
|
|
}
|
|
match self.parse_expr() {
|
|
Ok(e) => base = ast::StructRest::Base(e),
|
|
Err(mut e) if recover => {
|
|
e.emit();
|
|
self.recover_stmt();
|
|
}
|
|
Err(e) => return Err(e),
|
|
}
|
|
self.recover_struct_comma_after_dotdot(exp_span);
|
|
break;
|
|
}
|
|
|
|
let recovery_field = self.find_struct_error_after_field_looking_code();
|
|
let parsed_field = match self.parse_expr_field() {
|
|
Ok(f) => Some(f),
|
|
Err(mut e) => {
|
|
if pth == kw::Async {
|
|
async_block_err(&mut e, pth.span);
|
|
} else {
|
|
e.span_label(pth.span, "while parsing this struct");
|
|
}
|
|
|
|
if let Some((ident, _)) = self.token.ident()
|
|
&& !self.token.is_reserved_ident()
|
|
&& self.look_ahead(1, |t| {
|
|
AssocOp::from_token(t).is_some()
|
|
|| matches!(t.kind, token::OpenDelim(_))
|
|
|| t.kind == token::Dot
|
|
})
|
|
{
|
|
// Looks like they tried to write a shorthand, complex expression.
|
|
e.span_suggestion_verbose(
|
|
self.token.span.shrink_to_lo(),
|
|
"try naming a field",
|
|
&format!("{ident}: ",),
|
|
Applicability::MaybeIncorrect,
|
|
);
|
|
}
|
|
if in_if_guard && close_delim == Delimiter::Brace {
|
|
return Err(e);
|
|
}
|
|
|
|
if !recover {
|
|
return Err(e);
|
|
}
|
|
|
|
e.emit();
|
|
|
|
// If the next token is a comma, then try to parse
|
|
// what comes next as additional fields, rather than
|
|
// bailing out until next `}`.
|
|
if self.token != token::Comma {
|
|
self.recover_stmt_(SemiColonMode::Comma, BlockMode::Ignore);
|
|
if self.token != token::Comma {
|
|
break;
|
|
}
|
|
}
|
|
|
|
None
|
|
}
|
|
};
|
|
|
|
let is_shorthand = parsed_field.as_ref().is_some_and(|f| f.is_shorthand);
|
|
// A shorthand field can be turned into a full field with `:`.
|
|
// We should point this out.
|
|
self.check_or_expected(!is_shorthand, TokenType::Token(token::Colon));
|
|
|
|
match self.expect_one_of(&[token::Comma], &[token::CloseDelim(close_delim)]) {
|
|
Ok(_) => {
|
|
if let Some(f) = parsed_field.or(recovery_field) {
|
|
// Only include the field if there's no parse error for the field name.
|
|
fields.push(f);
|
|
}
|
|
}
|
|
Err(mut e) => {
|
|
if pth == kw::Async {
|
|
async_block_err(&mut e, pth.span);
|
|
} else {
|
|
e.span_label(pth.span, "while parsing this struct");
|
|
if let Some(f) = recovery_field {
|
|
fields.push(f);
|
|
e.span_suggestion(
|
|
self.prev_token.span.shrink_to_hi(),
|
|
"try adding a comma",
|
|
",",
|
|
Applicability::MachineApplicable,
|
|
);
|
|
}
|
|
}
|
|
if !recover {
|
|
return Err(e);
|
|
}
|
|
e.emit();
|
|
self.recover_stmt_(SemiColonMode::Comma, BlockMode::Ignore);
|
|
self.eat(&token::Comma);
|
|
}
|
|
}
|
|
}
|
|
Ok((fields, base, recover_async))
|
|
}
|
|
|
|
/// Precondition: already parsed the '{'.
|
|
pub(super) fn parse_expr_struct(
|
|
&mut self,
|
|
qself: Option<P<ast::QSelf>>,
|
|
pth: ast::Path,
|
|
recover: bool,
|
|
) -> PResult<'a, P<Expr>> {
|
|
let lo = pth.span;
|
|
let (fields, base, recover_async) =
|
|
self.parse_struct_fields(pth.clone(), recover, Delimiter::Brace)?;
|
|
let span = lo.to(self.token.span);
|
|
self.expect(&token::CloseDelim(Delimiter::Brace))?;
|
|
let expr = if recover_async {
|
|
ExprKind::Err
|
|
} else {
|
|
ExprKind::Struct(P(ast::StructExpr { qself, path: pth, fields, rest: base }))
|
|
};
|
|
Ok(self.mk_expr(span, expr))
|
|
}
|
|
|
|
/// Use in case of error after field-looking code: `S { foo: () with a }`.
|
|
fn find_struct_error_after_field_looking_code(&self) -> Option<ExprField> {
|
|
match self.token.ident() {
|
|
Some((ident, is_raw))
|
|
if (is_raw || !ident.is_reserved())
|
|
&& self.look_ahead(1, |t| *t == token::Colon) =>
|
|
{
|
|
Some(ast::ExprField {
|
|
ident,
|
|
span: self.token.span,
|
|
expr: self.mk_expr_err(self.token.span),
|
|
is_shorthand: false,
|
|
attrs: AttrVec::new(),
|
|
id: DUMMY_NODE_ID,
|
|
is_placeholder: false,
|
|
})
|
|
}
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
fn recover_struct_comma_after_dotdot(&mut self, span: Span) {
|
|
if self.token != token::Comma {
|
|
return;
|
|
}
|
|
self.sess.emit_err(errors::CommaAfterBaseStruct {
|
|
span: span.to(self.prev_token.span),
|
|
comma: self.token.span,
|
|
});
|
|
self.recover_stmt();
|
|
}
|
|
|
|
fn recover_struct_field_dots(&mut self, close_delim: Delimiter) -> bool {
|
|
if !self.look_ahead(1, |t| *t == token::CloseDelim(close_delim))
|
|
&& self.eat(&token::DotDotDot)
|
|
{
|
|
// recover from typo of `...`, suggest `..`
|
|
let span = self.prev_token.span;
|
|
self.sess.emit_err(errors::MissingDotDot { token_span: span, sugg_span: span });
|
|
return true;
|
|
}
|
|
false
|
|
}
|
|
|
|
/// Converts an ident into 'label and emits an "expected a label, found an identifier" error.
|
|
fn recover_ident_into_label(&mut self, ident: Ident) -> Label {
|
|
// Convert `label` -> `'label`,
|
|
// so that nameres doesn't complain about non-existing label
|
|
let label = format!("'{}", ident.name);
|
|
let ident = Ident { name: Symbol::intern(&label), span: ident.span };
|
|
|
|
self.sess.emit_err(errors::ExpectedLabelFoundIdent {
|
|
span: ident.span,
|
|
start: ident.span.shrink_to_lo(),
|
|
});
|
|
|
|
Label { ident }
|
|
}
|
|
|
|
/// Parses `ident (COLON expr)?`.
|
|
fn parse_expr_field(&mut self) -> PResult<'a, ExprField> {
|
|
let attrs = self.parse_outer_attributes()?;
|
|
self.recover_diff_marker();
|
|
self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| {
|
|
let lo = this.token.span;
|
|
|
|
// Check if a colon exists one ahead. This means we're parsing a fieldname.
|
|
let is_shorthand = !this.look_ahead(1, |t| t == &token::Colon || t == &token::Eq);
|
|
// Proactively check whether parsing the field will be incorrect.
|
|
let is_wrong = this.token.is_ident()
|
|
&& !this.token.is_reserved_ident()
|
|
&& !this.look_ahead(1, |t| {
|
|
t == &token::Colon
|
|
|| t == &token::Eq
|
|
|| t == &token::Comma
|
|
|| t == &token::CloseDelim(Delimiter::Brace)
|
|
|| t == &token::CloseDelim(Delimiter::Parenthesis)
|
|
});
|
|
if is_wrong {
|
|
return Err(this.dcx().create_err(errors::ExpectedStructField {
|
|
span: this.look_ahead(1, |t| t.span),
|
|
ident_span: this.token.span,
|
|
token: this.look_ahead(1, |t| t.clone()),
|
|
}));
|
|
}
|
|
let (ident, expr) = if is_shorthand {
|
|
// Mimic `x: x` for the `x` field shorthand.
|
|
let ident = this.parse_ident_common(false)?;
|
|
let path = ast::Path::from_ident(ident);
|
|
(ident, this.mk_expr(ident.span, ExprKind::Path(None, path)))
|
|
} else {
|
|
let ident = this.parse_field_name()?;
|
|
this.error_on_eq_field_init(ident);
|
|
this.bump(); // `:`
|
|
(ident, this.parse_expr()?)
|
|
};
|
|
|
|
Ok((
|
|
ast::ExprField {
|
|
ident,
|
|
span: lo.to(expr.span),
|
|
expr,
|
|
is_shorthand,
|
|
attrs,
|
|
id: DUMMY_NODE_ID,
|
|
is_placeholder: false,
|
|
},
|
|
TrailingToken::MaybeComma,
|
|
))
|
|
})
|
|
}
|
|
|
|
/// Check for `=`. This means the source incorrectly attempts to
|
|
/// initialize a field with an eq rather than a colon.
|
|
fn error_on_eq_field_init(&self, field_name: Ident) {
|
|
if self.token != token::Eq {
|
|
return;
|
|
}
|
|
|
|
self.sess.emit_err(errors::EqFieldInit {
|
|
span: self.token.span,
|
|
eq: field_name.span.shrink_to_hi().to(self.token.span),
|
|
});
|
|
}
|
|
|
|
fn err_dotdotdot_syntax(&self, span: Span) {
|
|
self.sess.emit_err(errors::DotDotDot { span });
|
|
}
|
|
|
|
fn err_larrow_operator(&self, span: Span) {
|
|
self.sess.emit_err(errors::LeftArrowOperator { span });
|
|
}
|
|
|
|
fn mk_assign_op(&self, binop: BinOp, lhs: P<Expr>, rhs: P<Expr>) -> ExprKind {
|
|
ExprKind::AssignOp(binop, lhs, rhs)
|
|
}
|
|
|
|
fn mk_range(
|
|
&mut self,
|
|
start: Option<P<Expr>>,
|
|
end: Option<P<Expr>>,
|
|
limits: RangeLimits,
|
|
) -> ExprKind {
|
|
if end.is_none() && limits == RangeLimits::Closed {
|
|
self.inclusive_range_with_incorrect_end();
|
|
ExprKind::Err
|
|
} else {
|
|
ExprKind::Range(start, end, limits)
|
|
}
|
|
}
|
|
|
|
fn mk_unary(&self, unop: UnOp, expr: P<Expr>) -> ExprKind {
|
|
ExprKind::Unary(unop, expr)
|
|
}
|
|
|
|
fn mk_binary(&self, binop: BinOp, lhs: P<Expr>, rhs: P<Expr>) -> ExprKind {
|
|
ExprKind::Binary(binop, lhs, rhs)
|
|
}
|
|
|
|
fn mk_index(&self, expr: P<Expr>, idx: P<Expr>, brackets_span: Span) -> ExprKind {
|
|
ExprKind::Index(expr, idx, brackets_span)
|
|
}
|
|
|
|
fn mk_call(&self, f: P<Expr>, args: ThinVec<P<Expr>>) -> ExprKind {
|
|
ExprKind::Call(f, args)
|
|
}
|
|
|
|
fn mk_await_expr(&mut self, self_arg: P<Expr>, lo: Span) -> P<Expr> {
|
|
let span = lo.to(self.prev_token.span);
|
|
let await_expr = self.mk_expr(span, ExprKind::Await(self_arg, self.prev_token.span));
|
|
self.recover_from_await_method_call();
|
|
await_expr
|
|
}
|
|
|
|
pub(crate) fn mk_expr_with_attrs(&self, span: Span, kind: ExprKind, attrs: AttrVec) -> P<Expr> {
|
|
P(Expr { kind, span, attrs, id: DUMMY_NODE_ID, tokens: None })
|
|
}
|
|
|
|
pub(crate) fn mk_expr(&self, span: Span, kind: ExprKind) -> P<Expr> {
|
|
P(Expr { kind, span, attrs: AttrVec::new(), id: DUMMY_NODE_ID, tokens: None })
|
|
}
|
|
|
|
pub(super) fn mk_expr_err(&self, span: Span) -> P<Expr> {
|
|
self.mk_expr(span, ExprKind::Err)
|
|
}
|
|
|
|
/// Create expression span ensuring the span of the parent node
|
|
/// is larger than the span of lhs and rhs, including the attributes.
|
|
fn mk_expr_sp(&self, lhs: &P<Expr>, lhs_span: Span, rhs_span: Span) -> Span {
|
|
lhs.attrs
|
|
.iter()
|
|
.find(|a| a.style == AttrStyle::Outer)
|
|
.map_or(lhs_span, |a| a.span)
|
|
.to(rhs_span)
|
|
}
|
|
|
|
fn collect_tokens_for_expr(
|
|
&mut self,
|
|
attrs: AttrWrapper,
|
|
f: impl FnOnce(&mut Self, ast::AttrVec) -> PResult<'a, P<Expr>>,
|
|
) -> PResult<'a, P<Expr>> {
|
|
self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| {
|
|
let res = f(this, attrs)?;
|
|
let trailing = if this.restrictions.contains(Restrictions::STMT_EXPR)
|
|
&& this.token.kind == token::Semi
|
|
{
|
|
TrailingToken::Semi
|
|
} else if this.token.kind == token::Gt {
|
|
TrailingToken::Gt
|
|
} else {
|
|
// FIXME - pass this through from the place where we know
|
|
// we need a comma, rather than assuming that `#[attr] expr,`
|
|
// always captures a trailing comma
|
|
TrailingToken::MaybeComma
|
|
};
|
|
Ok((res, trailing))
|
|
})
|
|
}
|
|
}
|
|
|
|
/// Used to forbid `let` expressions in certain syntactic locations.
|
|
#[derive(Clone, Copy, Subdiagnostic)]
|
|
pub(crate) enum ForbiddenLetReason {
|
|
/// `let` is not valid and the source environment is not important
|
|
OtherForbidden,
|
|
/// A let chain with the `||` operator
|
|
#[note(parse_not_supported_or)]
|
|
NotSupportedOr(#[primary_span] Span),
|
|
/// A let chain with invalid parentheses
|
|
///
|
|
/// For example, `let 1 = 1 && (expr && expr)` is allowed
|
|
/// but `(let 1 = 1 && (let 1 = 1 && (let 1 = 1))) && let a = 1` is not
|
|
#[note(parse_not_supported_parentheses)]
|
|
NotSupportedParentheses(#[primary_span] Span),
|
|
}
|
|
|
|
/// Visitor to check for invalid/unstable use of `ExprKind::Let` that can't
|
|
/// easily be caught in parsing. For example:
|
|
///
|
|
/// ```rust,ignore (example)
|
|
/// // Only know that the let isn't allowed once the `||` token is reached
|
|
/// if let Some(x) = y || true {}
|
|
/// // Only know that the let isn't allowed once the second `=` token is reached.
|
|
/// if let Some(x) = y && z = 1 {}
|
|
/// ```
|
|
struct CondChecker<'a> {
|
|
parser: &'a Parser<'a>,
|
|
forbid_let_reason: Option<ForbiddenLetReason>,
|
|
missing_let: Option<errors::MaybeMissingLet>,
|
|
comparison: Option<errors::MaybeComparison>,
|
|
}
|
|
|
|
impl<'a> CondChecker<'a> {
|
|
fn new(parser: &'a Parser<'a>) -> Self {
|
|
CondChecker { parser, forbid_let_reason: None, missing_let: None, comparison: None }
|
|
}
|
|
}
|
|
|
|
impl MutVisitor for CondChecker<'_> {
|
|
fn visit_expr(&mut self, e: &mut P<Expr>) {
|
|
use ForbiddenLetReason::*;
|
|
|
|
let span = e.span;
|
|
match e.kind {
|
|
ExprKind::Let(_, _, _, ref mut is_recovered @ None) => {
|
|
if let Some(reason) = self.forbid_let_reason {
|
|
*is_recovered =
|
|
Some(self.parser.sess.emit_err(errors::ExpectedExpressionFoundLet {
|
|
span,
|
|
reason,
|
|
missing_let: self.missing_let,
|
|
comparison: self.comparison,
|
|
}));
|
|
} else {
|
|
self.parser.sess.gated_spans.gate(sym::let_chains, span);
|
|
}
|
|
}
|
|
ExprKind::Binary(Spanned { node: BinOpKind::And, .. }, _, _) => {
|
|
noop_visit_expr(e, self);
|
|
}
|
|
ExprKind::Binary(Spanned { node: BinOpKind::Or, span: or_span }, _, _)
|
|
if let None | Some(NotSupportedOr(_)) = self.forbid_let_reason =>
|
|
{
|
|
let forbid_let_reason = self.forbid_let_reason;
|
|
self.forbid_let_reason = Some(NotSupportedOr(or_span));
|
|
noop_visit_expr(e, self);
|
|
self.forbid_let_reason = forbid_let_reason;
|
|
}
|
|
ExprKind::Paren(ref inner)
|
|
if let None | Some(NotSupportedParentheses(_)) = self.forbid_let_reason =>
|
|
{
|
|
let forbid_let_reason = self.forbid_let_reason;
|
|
self.forbid_let_reason = Some(NotSupportedParentheses(inner.span));
|
|
noop_visit_expr(e, self);
|
|
self.forbid_let_reason = forbid_let_reason;
|
|
}
|
|
ExprKind::Assign(ref lhs, _, span) => {
|
|
let forbid_let_reason = self.forbid_let_reason;
|
|
self.forbid_let_reason = Some(OtherForbidden);
|
|
let missing_let = self.missing_let;
|
|
if let ExprKind::Binary(_, _, rhs) = &lhs.kind
|
|
&& let ExprKind::Path(_, _)
|
|
| ExprKind::Struct(_)
|
|
| ExprKind::Call(_, _)
|
|
| ExprKind::Array(_) = rhs.kind
|
|
{
|
|
self.missing_let =
|
|
Some(errors::MaybeMissingLet { span: rhs.span.shrink_to_lo() });
|
|
}
|
|
let comparison = self.comparison;
|
|
self.comparison = Some(errors::MaybeComparison { span: span.shrink_to_hi() });
|
|
noop_visit_expr(e, self);
|
|
self.forbid_let_reason = forbid_let_reason;
|
|
self.missing_let = missing_let;
|
|
self.comparison = comparison;
|
|
}
|
|
ExprKind::Unary(_, _)
|
|
| ExprKind::Await(_, _)
|
|
| ExprKind::AssignOp(_, _, _)
|
|
| ExprKind::Range(_, _, _)
|
|
| ExprKind::Try(_)
|
|
| ExprKind::AddrOf(_, _, _)
|
|
| ExprKind::Binary(_, _, _)
|
|
| ExprKind::Field(_, _)
|
|
| ExprKind::Index(_, _, _)
|
|
| ExprKind::Call(_, _)
|
|
| ExprKind::MethodCall(_)
|
|
| ExprKind::Tup(_)
|
|
| ExprKind::Paren(_) => {
|
|
let forbid_let_reason = self.forbid_let_reason;
|
|
self.forbid_let_reason = Some(OtherForbidden);
|
|
noop_visit_expr(e, self);
|
|
self.forbid_let_reason = forbid_let_reason;
|
|
}
|
|
ExprKind::Cast(ref mut op, _) | ExprKind::Type(ref mut op, _) => {
|
|
let forbid_let_reason = self.forbid_let_reason;
|
|
self.forbid_let_reason = Some(OtherForbidden);
|
|
self.visit_expr(op);
|
|
self.forbid_let_reason = forbid_let_reason;
|
|
}
|
|
ExprKind::Let(_, _, _, Some(_))
|
|
| ExprKind::Array(_)
|
|
| ExprKind::ConstBlock(_)
|
|
| ExprKind::Lit(_)
|
|
| ExprKind::If(_, _, _)
|
|
| ExprKind::While(_, _, _)
|
|
| ExprKind::ForLoop { .. }
|
|
| ExprKind::Loop(_, _, _)
|
|
| ExprKind::Match(_, _)
|
|
| ExprKind::Closure(_)
|
|
| ExprKind::Block(_, _)
|
|
| ExprKind::Gen(_, _, _)
|
|
| ExprKind::TryBlock(_)
|
|
| ExprKind::Underscore
|
|
| ExprKind::Path(_, _)
|
|
| ExprKind::Break(_, _)
|
|
| ExprKind::Continue(_)
|
|
| ExprKind::Ret(_)
|
|
| ExprKind::InlineAsm(_)
|
|
| ExprKind::OffsetOf(_, _)
|
|
| ExprKind::MacCall(_)
|
|
| ExprKind::Struct(_)
|
|
| ExprKind::Repeat(_, _)
|
|
| ExprKind::Yield(_)
|
|
| ExprKind::Yeet(_)
|
|
| ExprKind::Become(_)
|
|
| ExprKind::IncludedBytes(_)
|
|
| ExprKind::FormatArgs(_)
|
|
| ExprKind::Err => {
|
|
// These would forbid any let expressions they contain already.
|
|
}
|
|
}
|
|
}
|
|
}
|