itsscb/rust-analyzer
1
0
Fork 0
mirror of https://github.com/rust-lang/rust-analyzer.git synced 2025-10-01 11:31:15 +00:00
Code Issues Packages Projects Releases Wiki Activity
rust-analyzer/crates/hir-ty/src/infer/expr.rs
Chayim Refael Friedman 99ce53b1d7 Add two new diagnostics: one for mismatch in generic arguments count, and another for mismatch in their kind 
Also known as E0747 and E0107.

And by the way, rewrite how we lower generic arguments and deduplicate it between paths and method calls. The new version is taken almost straight from rustc.

This commit also changes the binders of `generic_defaults()`, to only include the binders of the arguments up to (and not including) the current argument. This make it easier to handle it in the rewritten lowering of generic args. It's also how rustc does it.
2025-04-22 14:55:43 +03:00

2398 lines
103 KiB
Rust
Raw Blame History

//! Type inference for expressions.
use std::{
iter::{repeat, repeat_with},
mem,
};
use chalk_ir::{DebruijnIndex, Mutability, TyVariableKind, cast::Cast};
use either::Either;
use hir_def::{
BlockId, FieldId, GenericDefId, GenericParamId, ItemContainerId, Lookup, TupleFieldId, TupleId,
expr_store::path::{GenericArg, GenericArgs, Path},
hir::{
ArithOp, Array, AsmOperand, AsmOptions, BinaryOp, Expr, ExprId, ExprOrPatId, LabelId,
Literal, Pat, PatId, Statement, UnaryOp, generics::GenericParamDataRef,
},
lang_item::{LangItem, LangItemTarget},
resolver::ValueNs,
};
use hir_expand::name::Name;
use intern::sym;
use stdx::always;
use syntax::ast::RangeOp;
use crate::{
Adjust, Adjustment, AdtId, AutoBorrow, Binders, CallableDefId, CallableSig, DeclContext,
DeclOrigin, IncorrectGenericsLenKind, Interner, Rawness, Scalar, Substitution,
TraitEnvironment, TraitRef, Ty, TyBuilder, TyExt, TyKind,
autoderef::{Autoderef, builtin_deref, deref_by_trait},
consteval,
generics::generics,
infer::{
BreakableKind,
coerce::{CoerceMany, CoerceNever, CoercionCause},
find_continuable,
pat::contains_explicit_ref_binding,
},
lang_items::lang_items_for_bin_op,
lower::{
GenericArgsPosition, ParamLoweringMode, lower_to_chalk_mutability,
path::{GenericArgsLowerer, TypeLikeConst, substs_from_args_and_bindings},
},
mapping::{ToChalk, from_chalk},
method_resolution::{self, VisibleFromModule},
primitive::{self, UintTy},
static_lifetime, to_chalk_trait_id,
traits::FnTrait,
};
use super::{
BreakableContext, Diverges, Expectation, InferenceContext, InferenceDiagnostic, TypeMismatch,
cast::CastCheck, coerce::auto_deref_adjust_steps, find_breakable,
};
#[derive(Clone, Copy, PartialEq, Eq)]
pub(crate) enum ExprIsRead {
Yes,
No,
}
impl InferenceContext<'_> {
pub(crate) fn infer_expr(
&mut self,
tgt_expr: ExprId,
expected: &Expectation,
is_read: ExprIsRead,
) -> Ty {
let ty = self.infer_expr_inner(tgt_expr, expected, is_read);
if let Some(expected_ty) = expected.only_has_type(&mut self.table) {
let could_unify = self.unify(&ty, &expected_ty);
if !could_unify {
self.result.type_mismatches.insert(
tgt_expr.into(),
TypeMismatch { expected: expected_ty, actual: ty.clone() },
);
}
}
ty
}
pub(crate) fn infer_expr_no_expect(&mut self, tgt_expr: ExprId, is_read: ExprIsRead) -> Ty {
self.infer_expr_inner(tgt_expr, &Expectation::None, is_read)
}
/// Infer type of expression with possibly implicit coerce to the expected type.
/// Return the type after possible coercion.
pub(super) fn infer_expr_coerce(
&mut self,
expr: ExprId,
expected: &Expectation,
is_read: ExprIsRead,
) -> Ty {
let ty = self.infer_expr_inner(expr, expected, is_read);
if let Some(target) = expected.only_has_type(&mut self.table) {
let coerce_never = if self.expr_guaranteed_to_constitute_read_for_never(expr, is_read) {
CoerceNever::Yes
} else {
CoerceNever::No
};
match self.coerce(Some(expr), &ty, &target, coerce_never) {
Ok(res) => res,
Err(_) => {
self.result.type_mismatches.insert(
expr.into(),
TypeMismatch { expected: target.clone(), actual: ty.clone() },
);
target
}
}
} else {
ty
}
}
/// Whether this expression constitutes a read of value of the type that
/// it evaluates to.
///
/// This is used to determine if we should consider the block to diverge
/// if the expression evaluates to `!`, and if we should insert a `NeverToAny`
/// coercion for values of type `!`.
///
/// This function generally returns `false` if the expression is a place
/// expression and the *parent* expression is the scrutinee of a match or
/// the pointee of an `&` addr-of expression, since both of those parent
/// expressions take a *place* and not a value.
pub(super) fn expr_guaranteed_to_constitute_read_for_never(
&mut self,
expr: ExprId,
is_read: ExprIsRead,
) -> bool {
// rustc does the place expr check first, but since we are feeding
// readness of the `expr` as a given value, we just can short-circuit
// the place expr check if it's true(see codes and comments below)
if is_read == ExprIsRead::Yes {
return true;
}
// We only care about place exprs. Anything else returns an immediate
// which would constitute a read. We don't care about distinguishing
// "syntactic" place exprs since if the base of a field projection is
// not a place then it would've been UB to read from it anyways since
// that constitutes a read.
if !self.is_syntactic_place_expr(expr) {
return true;
}
// rustc queries parent hir node of `expr` here and determine whether
// the current `expr` is read of value per its parent.
// But since we don't have hir node, we cannot follow such "bottom-up"
// method.
// So, we pass down such readness from the parent expression through the
// recursive `infer_expr*` calls in a "top-down" manner.
is_read == ExprIsRead::Yes
}
/// Whether this pattern constitutes a read of value of the scrutinee that
/// it is matching against. This is used to determine whether we should
/// perform `NeverToAny` coercions.
fn pat_guaranteed_to_constitute_read_for_never(&self, pat: PatId) -> bool {
match &self.body[pat] {
// Does not constitute a read.
Pat::Wild => false,
// This is unnecessarily restrictive when the pattern that doesn't
// constitute a read is unreachable.
//
// For example `match *never_ptr { value => {}, _ => {} }` or
// `match *never_ptr { _ if false => {}, value => {} }`.
//
// It is however fine to be restrictive here; only returning `true`
// can lead to unsoundness.
Pat::Or(subpats) => {
subpats.iter().all(|pat| self.pat_guaranteed_to_constitute_read_for_never(*pat))
}
// All of these constitute a read, or match on something that isn't `!`,
// which would require a `NeverToAny` coercion.
Pat::Bind { .. }
| Pat::TupleStruct { .. }
| Pat::Path(_)
| Pat::Tuple { .. }
| Pat::Box { .. }
| Pat::Ref { .. }
| Pat::Lit(_)
| Pat::Range { .. }
| Pat::Slice { .. }
| Pat::ConstBlock(_)
| Pat::Record { .. }
| Pat::Missing => true,
Pat::Expr(_) => unreachable!(
"we don't call pat_guaranteed_to_constitute_read_for_never() with assignments"
),
}
}
fn is_syntactic_place_expr(&self, expr: ExprId) -> bool {
match &self.body[expr] {
// Lang item paths cannot currently be local variables or statics.
Expr::Path(Path::LangItem(_, _)) => false,
Expr::Path(Path::Normal(path)) => path.type_anchor.is_none(),
Expr::Path(path) => self
.resolver
.resolve_path_in_value_ns_fully(self.db, path, self.body.expr_path_hygiene(expr))
.is_none_or(|res| matches!(res, ValueNs::LocalBinding(_) | ValueNs::StaticId(_))),
Expr::Underscore => true,
Expr::UnaryOp { op: UnaryOp::Deref, .. } => true,
Expr::Field { .. } | Expr::Index { .. } => true,
Expr::Call { .. }
| Expr::MethodCall { .. }
| Expr::Tuple { .. }
| Expr::If { .. }
| Expr::Match { .. }
| Expr::Closure { .. }
| Expr::Block { .. }
| Expr::Array(..)
| Expr::Break { .. }
| Expr::Continue { .. }
| Expr::Return { .. }
| Expr::Become { .. }
| Expr::Let { .. }
| Expr::Loop { .. }
| Expr::InlineAsm(..)
| Expr::OffsetOf(..)
| Expr::Literal(..)
| Expr::Const(..)
| Expr::UnaryOp { .. }
| Expr::BinaryOp { .. }
| Expr::Assignment { .. }
| Expr::Yield { .. }
| Expr::Cast { .. }
| Expr::Async { .. }
| Expr::Unsafe { .. }
| Expr::Await { .. }
| Expr::Ref { .. }
| Expr::Range { .. }
| Expr::Box { .. }
| Expr::RecordLit { .. }
| Expr::Yeet { .. }
| Expr::Missing => false,
}
}
fn infer_expr_coerce_never(
&mut self,
expr: ExprId,
expected: &Expectation,
is_read: ExprIsRead,
) -> Ty {
let ty = self.infer_expr_inner(expr, expected, is_read);
// While we don't allow *arbitrary* coercions here, we *do* allow
// coercions from `!` to `expected`.
if ty.is_never() {
if let Some(adjustments) = self.result.expr_adjustments.get(&expr) {
return if let [Adjustment { kind: Adjust::NeverToAny, target }] = &**adjustments {
target.clone()
} else {
self.err_ty()
};
}
if let Some(target) = expected.only_has_type(&mut self.table) {
self.coerce(Some(expr), &ty, &target, CoerceNever::Yes)
.expect("never-to-any coercion should always succeed")
} else {
ty
}
} else {
if let Some(expected_ty) = expected.only_has_type(&mut self.table) {
let could_unify = self.unify(&ty, &expected_ty);
if !could_unify {
self.result.type_mismatches.insert(
expr.into(),
TypeMismatch { expected: expected_ty, actual: ty.clone() },
);
}
}
ty
}
}
fn infer_expr_inner(
&mut self,
tgt_expr: ExprId,
expected: &Expectation,
is_read: ExprIsRead,
) -> Ty {
self.db.unwind_if_revision_cancelled();
let ty = match &self.body[tgt_expr] {
Expr::Missing => self.err_ty(),
&Expr::If { condition, then_branch, else_branch } => {
let expected = &expected.adjust_for_branches(&mut self.table);
self.infer_expr_coerce_never(
condition,
&Expectation::HasType(self.result.standard_types.bool_.clone()),
ExprIsRead::Yes,
);
let condition_diverges = mem::replace(&mut self.diverges, Diverges::Maybe);
let then_ty = self.infer_expr_inner(then_branch, expected, ExprIsRead::Yes);
let then_diverges = mem::replace(&mut self.diverges, Diverges::Maybe);
let mut coerce = CoerceMany::new(expected.coercion_target_type(&mut self.table));
coerce.coerce(self, Some(then_branch), &then_ty, CoercionCause::Expr(then_branch));
match else_branch {
Some(else_branch) => {
let else_ty = self.infer_expr_inner(else_branch, expected, ExprIsRead::Yes);
let else_diverges = mem::replace(&mut self.diverges, Diverges::Maybe);
coerce.coerce(
self,
Some(else_branch),
&else_ty,
CoercionCause::Expr(else_branch),
);
self.diverges = condition_diverges | then_diverges & else_diverges;
}
None => {
coerce.coerce_forced_unit(self, CoercionCause::Expr(tgt_expr));
self.diverges = condition_diverges;
}
}
coerce.complete(self)
}
&Expr::Let { pat, expr } => {
let child_is_read = if self.pat_guaranteed_to_constitute_read_for_never(pat) {
ExprIsRead::Yes
} else {
ExprIsRead::No
};
let input_ty = self.infer_expr(expr, &Expectation::none(), child_is_read);
self.infer_top_pat(
pat,
&input_ty,
Some(DeclContext { origin: DeclOrigin::LetExpr }),
);
self.result.standard_types.bool_.clone()
}
Expr::Block { statements, tail, label, id } => {
self.infer_block(tgt_expr, *id, statements, *tail, *label, expected)
}
Expr::Unsafe { id, statements, tail } => {
self.infer_block(tgt_expr, *id, statements, *tail, None, expected)
}
Expr::Const(id) => {
self.with_breakable_ctx(BreakableKind::Border, None, None, |this| {
this.infer_expr(*id, expected, ExprIsRead::Yes)
})
.1
}
Expr::Async { id, statements, tail } => {
self.infer_async_block(tgt_expr, id, statements, tail)
}
&Expr::Loop { body, label } => {
// FIXME: should be:
// let ty = expected.coercion_target_type(&mut self.table);
let ty = self.table.new_type_var();
let (breaks, ()) =
self.with_breakable_ctx(BreakableKind::Loop, Some(ty), label, |this| {
this.infer_expr(
body,
&Expectation::HasType(TyBuilder::unit()),
ExprIsRead::Yes,
);
});
match breaks {
Some(breaks) => {
self.diverges = Diverges::Maybe;
breaks
}
None => self.result.standard_types.never.clone(),
}
}
Expr::Closure { body, args, ret_type, arg_types, closure_kind, capture_by: _ } => self
.infer_closure(body, args, ret_type, arg_types, *closure_kind, tgt_expr, expected),
Expr::Call { callee, args, .. } => self.infer_call(tgt_expr, *callee, args, expected),
Expr::MethodCall { receiver, args, method_name, generic_args } => self
.infer_method_call(
tgt_expr,
*receiver,
args,
method_name,
generic_args.as_deref(),
expected,
),
Expr::Match { expr, arms } => {
let scrutinee_is_read = arms
.iter()
.all(|arm| self.pat_guaranteed_to_constitute_read_for_never(arm.pat));
let scrutinee_is_read =
if scrutinee_is_read { ExprIsRead::Yes } else { ExprIsRead::No };
let input_ty = self.infer_expr(*expr, &Expectation::none(), scrutinee_is_read);
if arms.is_empty() {
self.diverges = Diverges::Always;
self.result.standard_types.never.clone()
} else {
let matchee_diverges = mem::replace(&mut self.diverges, Diverges::Maybe);
let mut all_arms_diverge = Diverges::Always;
for arm in arms.iter() {
let input_ty = self.resolve_ty_shallow(&input_ty);
self.infer_top_pat(arm.pat, &input_ty, None);
}
let expected = expected.adjust_for_branches(&mut self.table);
let result_ty = match &expected {
// We don't coerce to `()` so that if the match expression is a
// statement it's branches can have any consistent type.
Expectation::HasType(ty) if *ty != self.result.standard_types.unit => {
ty.clone()
}
_ => self.table.new_type_var(),
};
let mut coerce = CoerceMany::new(result_ty);
for arm in arms.iter() {
if let Some(guard_expr) = arm.guard {
self.diverges = Diverges::Maybe;
self.infer_expr_coerce_never(
guard_expr,
&Expectation::HasType(self.result.standard_types.bool_.clone()),
ExprIsRead::Yes,
);
}
self.diverges = Diverges::Maybe;
let arm_ty = self.infer_expr_inner(arm.expr, &expected, ExprIsRead::Yes);
all_arms_diverge &= self.diverges;
coerce.coerce(self, Some(arm.expr), &arm_ty, CoercionCause::Expr(arm.expr));
}
self.diverges = matchee_diverges | all_arms_diverge;
coerce.complete(self)
}
}
Expr::Path(p) => self.infer_expr_path(p, tgt_expr.into(), tgt_expr),
&Expr::Continue { label } => {
if find_continuable(&mut self.breakables, label).is_none() {
self.push_diagnostic(InferenceDiagnostic::BreakOutsideOfLoop {
expr: tgt_expr,
is_break: false,
bad_value_break: false,
});
};
self.result.standard_types.never.clone()
}
&Expr::Break { expr, label } => {
let val_ty = if let Some(expr) = expr {
let opt_coerce_to = match find_breakable(&mut self.breakables, label) {
Some(ctxt) => match &ctxt.coerce {
Some(coerce) => coerce.expected_ty(),
None => {
self.push_diagnostic(InferenceDiagnostic::BreakOutsideOfLoop {
expr: tgt_expr,
is_break: true,
bad_value_break: true,
});
self.err_ty()
}
},
None => self.err_ty(),
};
self.infer_expr_inner(
expr,
&Expectation::HasType(opt_coerce_to),
ExprIsRead::Yes,
)
} else {
TyBuilder::unit()
};
match find_breakable(&mut self.breakables, label) {
Some(ctxt) => match ctxt.coerce.take() {
Some(mut coerce) => {
let cause = match expr {
Some(expr) => CoercionCause::Expr(expr),
None => CoercionCause::Expr(tgt_expr),
};
coerce.coerce(self, expr, &val_ty, cause);
// Avoiding borrowck
let ctxt = find_breakable(&mut self.breakables, label)
.expect("breakable stack changed during coercion");
ctxt.may_break = true;
ctxt.coerce = Some(coerce);
}
None => ctxt.may_break = true,
},
None => {
self.push_diagnostic(InferenceDiagnostic::BreakOutsideOfLoop {
expr: tgt_expr,
is_break: true,
bad_value_break: false,
});
}
}
self.result.standard_types.never.clone()
}
&Expr::Return { expr } => self.infer_expr_return(tgt_expr, expr),
&Expr::Become { expr } => self.infer_expr_become(expr),
Expr::Yield { expr } => {
if let Some((resume_ty, yield_ty)) = self.resume_yield_tys.clone() {
if let Some(expr) = expr {
self.infer_expr_coerce(
*expr,
&Expectation::has_type(yield_ty),
ExprIsRead::Yes,
);
} else {
let unit = self.result.standard_types.unit.clone();
let _ = self.coerce(Some(tgt_expr), &unit, &yield_ty, CoerceNever::Yes);
}
resume_ty
} else {
// FIXME: report error (yield expr in non-coroutine)
self.result.standard_types.unknown.clone()
}
}
Expr::Yeet { expr } => {
if let &Some(expr) = expr {
self.infer_expr_no_expect(expr, ExprIsRead::Yes);
}
self.result.standard_types.never.clone()
}
Expr::RecordLit { path, fields, spread, .. } => {
let (ty, def_id) = self.resolve_variant(tgt_expr.into(), path.as_deref(), false);
if let Some(t) = expected.only_has_type(&mut self.table) {
self.unify(&ty, &t);
}
let substs = ty
.as_adt()
.map(|(_, s)| s.clone())
.unwrap_or_else(|| Substitution::empty(Interner));
if let Some(variant) = def_id {
self.write_variant_resolution(tgt_expr.into(), variant);
}
match def_id {
_ if fields.is_empty() => {}
Some(def) => {
let field_types = self.db.field_types(def);
let variant_data = def.variant_data(self.db);
let visibilities = self.db.field_visibilities(def);
for field in fields.iter() {
let field_def = {
match variant_data.field(&field.name) {
Some(local_id) => {
if !visibilities[local_id]
.is_visible_from(self.db, self.resolver.module())
{
self.push_diagnostic(
InferenceDiagnostic::NoSuchField {
field: field.expr.into(),
private: true,
variant: def,
},
);
}
Some(local_id)
}
None => {
self.push_diagnostic(InferenceDiagnostic::NoSuchField {
field: field.expr.into(),
private: false,
variant: def,
});
None
}
}
};
let field_ty = field_def.map_or(self.err_ty(), |it| {
field_types[it].clone().substitute(Interner, &substs)
});
// Field type might have some unknown types
// FIXME: we may want to emit a single type variable for all instance of type fields?
let field_ty = self.insert_type_vars(field_ty);
self.infer_expr_coerce(
field.expr,
&Expectation::has_type(field_ty),
ExprIsRead::Yes,
);
}
}
None => {
for field in fields.iter() {
// Field projections don't constitute reads.
self.infer_expr_coerce(field.expr, &Expectation::None, ExprIsRead::No);
}
}
}
if let Some(expr) = spread {
self.infer_expr(*expr, &Expectation::has_type(ty.clone()), ExprIsRead::Yes);
}
ty
}
Expr::Field { expr, name } => self.infer_field_access(tgt_expr, *expr, name, expected),
Expr::Await { expr } => {
let inner_ty = self.infer_expr_inner(*expr, &Expectation::none(), ExprIsRead::Yes);
self.resolve_associated_type(inner_ty, self.resolve_future_future_output())
}
Expr::Cast { expr, type_ref } => {
let cast_ty = self.make_body_ty(*type_ref);
let expr_ty = self.infer_expr(
*expr,
&Expectation::Castable(cast_ty.clone()),
ExprIsRead::Yes,
);
self.deferred_cast_checks.push(CastCheck::new(
tgt_expr,
*expr,
expr_ty,
cast_ty.clone(),
));
cast_ty
}
Expr::Ref { expr, rawness, mutability } => {
let mutability = lower_to_chalk_mutability(*mutability);
let expectation = if let Some((exp_inner, exp_rawness, exp_mutability)) = expected
.only_has_type(&mut self.table)
.as_ref()
.and_then(|t| t.as_reference_or_ptr())
{
if exp_mutability == Mutability::Mut && mutability == Mutability::Not {
// FIXME: record type error - expected mut reference but found shared ref,
// which cannot be coerced
}
if exp_rawness == Rawness::Ref && *rawness == Rawness::RawPtr {
// FIXME: record type error - expected reference but found ptr,
// which cannot be coerced
}
Expectation::rvalue_hint(self, Ty::clone(exp_inner))
} else {
Expectation::none()
};
let inner_ty = self.infer_expr_inner(*expr, &expectation, ExprIsRead::Yes);
match rawness {
Rawness::RawPtr => TyKind::Raw(mutability, inner_ty),
Rawness::Ref => {
let lt = self.table.new_lifetime_var();
TyKind::Ref(mutability, lt, inner_ty)
}
}
.intern(Interner)
}
&Expr::Box { expr } => self.infer_expr_box(expr, expected),
Expr::UnaryOp { expr, op } => {
let inner_ty = self.infer_expr_inner(*expr, &Expectation::none(), ExprIsRead::Yes);
let inner_ty = self.resolve_ty_shallow(&inner_ty);
// FIXME: Note down method resolution her
match op {
UnaryOp::Deref => {
if let Some(deref_trait) = self.resolve_lang_trait(LangItem::Deref) {
if let Some(deref_fn) = self
.db
.trait_items(deref_trait)
.method_by_name(&Name::new_symbol_root(sym::deref))
{
// FIXME: this is wrong in multiple ways, subst is empty, and we emit it even for builtin deref (note that
// the mutability is not wrong, and will be fixed in `self.infer_mut`).
self.write_method_resolution(
tgt_expr,
deref_fn,
Substitution::empty(Interner),
);
}
}
if let Some(derefed) = builtin_deref(self.table.db, &inner_ty, true) {
self.resolve_ty_shallow(derefed)
} else {
deref_by_trait(&mut self.table, inner_ty, false)
.unwrap_or_else(|| self.err_ty())
}
}
UnaryOp::Neg => {
match inner_ty.kind(Interner) {
// Fast path for builtins
TyKind::Scalar(Scalar::Int(_) | Scalar::Uint(_) | Scalar::Float(_))
| TyKind::InferenceVar(
_,
TyVariableKind::Integer | TyVariableKind::Float,
) => inner_ty,
// Otherwise we resolve via the std::ops::Neg trait
_ => self
.resolve_associated_type(inner_ty, self.resolve_ops_neg_output()),
}
}
UnaryOp::Not => {
match inner_ty.kind(Interner) {
// Fast path for builtins
TyKind::Scalar(Scalar::Bool | Scalar::Int(_) | Scalar::Uint(_))
| TyKind::InferenceVar(_, TyVariableKind::Integer) => inner_ty,
// Otherwise we resolve via the std::ops::Not trait
_ => self
.resolve_associated_type(inner_ty, self.resolve_ops_not_output()),
}
}
}
}
Expr::BinaryOp { lhs, rhs, op } => match op {
Some(BinaryOp::LogicOp(_)) => {
let bool_ty = self.result.standard_types.bool_.clone();
self.infer_expr_coerce(
*lhs,
&Expectation::HasType(bool_ty.clone()),
ExprIsRead::Yes,
);
let lhs_diverges = self.diverges;
self.infer_expr_coerce(
*rhs,
&Expectation::HasType(bool_ty.clone()),
ExprIsRead::Yes,
);
// Depending on the LHS' value, the RHS can never execute.
self.diverges = lhs_diverges;
bool_ty
}
Some(op) => self.infer_overloadable_binop(*lhs, *op, *rhs, tgt_expr),
_ => self.err_ty(),
},
&Expr::Assignment { target, value } => {
// In ordinary (non-destructuring) assignments, the type of
// `lhs` must be inferred first so that the ADT fields
// instantiations in RHS can be coerced to it. Note that this
// cannot happen in destructuring assignments because of how
// they are desugared.
let lhs_ty = match &self.body[target] {
// LHS of assignment doesn't constitute reads.
&Pat::Expr(expr) => {
Some(self.infer_expr(expr, &Expectation::none(), ExprIsRead::No))
}
Pat::Path(path) => Some(self.infer_expr_path(path, target.into(), tgt_expr)),
_ => None,
};
if let Some(lhs_ty) = lhs_ty {
self.write_pat_ty(target, lhs_ty.clone());
self.infer_expr_coerce(value, &Expectation::has_type(lhs_ty), ExprIsRead::No);
} else {
let rhs_ty = self.infer_expr(value, &Expectation::none(), ExprIsRead::Yes);
let resolver_guard =
self.resolver.update_to_inner_scope(self.db, self.owner, tgt_expr);
self.inside_assignment = true;
self.infer_top_pat(target, &rhs_ty, None);
self.inside_assignment = false;
self.resolver.reset_to_guard(resolver_guard);
}
self.result.standard_types.unit.clone()
}
Expr::Range { lhs, rhs, range_type } => {
let lhs_ty =
lhs.map(|e| self.infer_expr_inner(e, &Expectation::none(), ExprIsRead::Yes));
let rhs_expect = lhs_ty
.as_ref()
.map_or_else(Expectation::none, |ty| Expectation::has_type(ty.clone()));
let rhs_ty = rhs.map(|e| self.infer_expr(e, &rhs_expect, ExprIsRead::Yes));
match (range_type, lhs_ty, rhs_ty) {
(RangeOp::Exclusive, None, None) => match self.resolve_range_full() {
Some(adt) => TyBuilder::adt(self.db, adt).build(),
None => self.err_ty(),
},
(RangeOp::Exclusive, None, Some(ty)) => match self.resolve_range_to() {
Some(adt) => TyBuilder::adt(self.db, adt).push(ty).build(),
None => self.err_ty(),
},
(RangeOp::Inclusive, None, Some(ty)) => {
match self.resolve_range_to_inclusive() {
Some(adt) => TyBuilder::adt(self.db, adt).push(ty).build(),
None => self.err_ty(),
}
}
(RangeOp::Exclusive, Some(_), Some(ty)) => match self.resolve_range() {
Some(adt) => TyBuilder::adt(self.db, adt).push(ty).build(),
None => self.err_ty(),
},
(RangeOp::Inclusive, Some(_), Some(ty)) => {
match self.resolve_range_inclusive() {
Some(adt) => TyBuilder::adt(self.db, adt).push(ty).build(),
None => self.err_ty(),
}
}
(RangeOp::Exclusive, Some(ty), None) => match self.resolve_range_from() {
Some(adt) => TyBuilder::adt(self.db, adt).push(ty).build(),
None => self.err_ty(),
},
(RangeOp::Inclusive, _, None) => self.err_ty(),
}
}
Expr::Index { base, index } => {
let base_ty = self.infer_expr_inner(*base, &Expectation::none(), ExprIsRead::Yes);
let index_ty = self.infer_expr(*index, &Expectation::none(), ExprIsRead::Yes);
if let Some(index_trait) = self.resolve_lang_trait(LangItem::Index) {
let canonicalized = self.canonicalize(base_ty.clone());
let receiver_adjustments = method_resolution::resolve_indexing_op(
self.db,
self.table.trait_env.clone(),
canonicalized,
index_trait,
);
let (self_ty, mut adj) = receiver_adjustments
.map_or((self.err_ty(), Vec::new()), |adj| {
adj.apply(&mut self.table, base_ty)
});
// mutability will be fixed up in `InferenceContext::infer_mut`;
adj.push(Adjustment::borrow(
Mutability::Not,
self_ty.clone(),
self.table.new_lifetime_var(),
));
self.write_expr_adj(*base, adj);
if let Some(func) = self
.db
.trait_items(index_trait)
.method_by_name(&Name::new_symbol_root(sym::index))
{
let subst = TyBuilder::subst_for_def(self.db, index_trait, None);
if subst.remaining() != 2 {
return self.err_ty();
}
let subst = subst.push(self_ty.clone()).push(index_ty.clone()).build();
self.write_method_resolution(tgt_expr, func, subst);
}
let assoc = self.resolve_ops_index_output();
self.resolve_associated_type_with_params(
self_ty.clone(),
assoc,
&[index_ty.clone().cast(Interner)],
)
} else {
self.err_ty()
}
}
Expr::Tuple { exprs, .. } => {
let mut tys = match expected
.only_has_type(&mut self.table)
.as_ref()
.map(|t| t.kind(Interner))
{
Some(TyKind::Tuple(_, substs)) => substs
.iter(Interner)
.map(|a| a.assert_ty_ref(Interner).clone())
.chain(repeat_with(|| self.table.new_type_var()))
.take(exprs.len())
.collect::<Vec<_>>(),
_ => (0..exprs.len()).map(|_| self.table.new_type_var()).collect(),
};
for (expr, ty) in exprs.iter().zip(tys.iter_mut()) {
*ty = self.infer_expr_coerce(
*expr,
&Expectation::has_type(ty.clone()),
ExprIsRead::Yes,
);
}
TyKind::Tuple(tys.len(), Substitution::from_iter(Interner, tys)).intern(Interner)
}
Expr::Array(array) => self.infer_expr_array(array, expected),
Expr::Literal(lit) => match lit {
Literal::Bool(..) => self.result.standard_types.bool_.clone(),
Literal::String(..) => {
TyKind::Ref(Mutability::Not, static_lifetime(), TyKind::Str.intern(Interner))
.intern(Interner)
}
Literal::ByteString(bs) => {
let byte_type = TyKind::Scalar(Scalar::Uint(UintTy::U8)).intern(Interner);
let len = consteval::usize_const(
self.db,
Some(bs.len() as u128),
self.resolver.krate(),
);
let array_type = TyKind::Array(byte_type, len).intern(Interner);
TyKind::Ref(Mutability::Not, static_lifetime(), array_type).intern(Interner)
}
Literal::CString(..) => TyKind::Ref(
Mutability::Not,
static_lifetime(),
self.resolve_lang_item(LangItem::CStr)
.and_then(LangItemTarget::as_struct)
.map_or_else(
|| self.err_ty(),
|strukt| {
TyKind::Adt(AdtId(strukt.into()), Substitution::empty(Interner))
.intern(Interner)
},
),
)
.intern(Interner),
Literal::Char(..) => TyKind::Scalar(Scalar::Char).intern(Interner),
Literal::Int(_v, ty) => match ty {
Some(int_ty) => {
TyKind::Scalar(Scalar::Int(primitive::int_ty_from_builtin(*int_ty)))
.intern(Interner)
}
None => {
let expected_ty = expected.to_option(&mut self.table);
let opt_ty = match expected_ty.as_ref().map(|it| it.kind(Interner)) {
Some(TyKind::Scalar(Scalar::Int(_) | Scalar::Uint(_))) => expected_ty,
Some(TyKind::Scalar(Scalar::Char)) => {
Some(TyKind::Scalar(Scalar::Uint(UintTy::U8)).intern(Interner))
}
Some(TyKind::Raw(..) | TyKind::FnDef(..) | TyKind::Function(..)) => {
Some(TyKind::Scalar(Scalar::Uint(UintTy::Usize)).intern(Interner))
}
_ => None,
};
opt_ty.unwrap_or_else(|| self.table.new_integer_var())
}
},
Literal::Uint(_v, ty) => match ty {
Some(int_ty) => {
TyKind::Scalar(Scalar::Uint(primitive::uint_ty_from_builtin(*int_ty)))
.intern(Interner)
}
None => {
let expected_ty = expected.to_option(&mut self.table);
let opt_ty = match expected_ty.as_ref().map(|it| it.kind(Interner)) {
Some(TyKind::Scalar(Scalar::Int(_) | Scalar::Uint(_))) => expected_ty,
Some(TyKind::Scalar(Scalar::Char)) => {
Some(TyKind::Scalar(Scalar::Uint(UintTy::U8)).intern(Interner))
}
Some(TyKind::Raw(..) | TyKind::FnDef(..) | TyKind::Function(..)) => {
Some(TyKind::Scalar(Scalar::Uint(UintTy::Usize)).intern(Interner))
}
_ => None,
};
opt_ty.unwrap_or_else(|| self.table.new_integer_var())
}
},
Literal::Float(_v, ty) => match ty {
Some(float_ty) => {
TyKind::Scalar(Scalar::Float(primitive::float_ty_from_builtin(*float_ty)))
.intern(Interner)
}
None => {
let opt_ty = expected.to_option(&mut self.table).filter(|ty| {
matches!(ty.kind(Interner), TyKind::Scalar(Scalar::Float(_)))
});
opt_ty.unwrap_or_else(|| self.table.new_float_var())
}
},
},
Expr::Underscore => {
// Underscore expression is an error, we render a specialized diagnostic
// to let the user know what type is expected though.
let expected = expected.to_option(&mut self.table).unwrap_or_else(|| self.err_ty());
self.push_diagnostic(InferenceDiagnostic::TypedHole {
expr: tgt_expr,
expected: expected.clone(),
});
expected
}
Expr::OffsetOf(_) => TyKind::Scalar(Scalar::Uint(UintTy::Usize)).intern(Interner),
Expr::InlineAsm(asm) => {
let mut check_expr_asm_operand = |expr, is_input: bool| {
let ty = self.infer_expr_no_expect(expr, ExprIsRead::Yes);
// If this is an input value, we require its type to be fully resolved
// at this point. This allows us to provide helpful coercions which help
// pass the type candidate list in a later pass.
//
// We don't require output types to be resolved at this point, which
// allows them to be inferred based on how they are used later in the
// function.
if is_input {
let ty = self.resolve_ty_shallow(&ty);
match ty.kind(Interner) {
TyKind::FnDef(def, parameters) => {
let fnptr_ty = TyKind::Function(
CallableSig::from_def(self.db, *def, parameters).to_fn_ptr(),
)
.intern(Interner);
_ = self.coerce(Some(expr), &ty, &fnptr_ty, CoerceNever::Yes);
}
TyKind::Ref(mutbl, _, base_ty) => {
let ptr_ty = TyKind::Raw(*mutbl, base_ty.clone()).intern(Interner);
_ = self.coerce(Some(expr), &ty, &ptr_ty, CoerceNever::Yes);
}
_ => {}
}
}
};
let diverge = asm.options.contains(AsmOptions::NORETURN);
asm.operands.iter().for_each(|(_, operand)| match *operand {
AsmOperand::In { expr, .. } => check_expr_asm_operand(expr, true),
AsmOperand::Out { expr: Some(expr), .. } | AsmOperand::InOut { expr, .. } => {
check_expr_asm_operand(expr, false)
}
AsmOperand::Out { expr: None, .. } => (),
AsmOperand::SplitInOut { in_expr, out_expr, .. } => {
check_expr_asm_operand(in_expr, true);
if let Some(out_expr) = out_expr {
check_expr_asm_operand(out_expr, false);
}
}
// FIXME
AsmOperand::Label(_) => (),
// FIXME
AsmOperand::Const(_) => (),
// FIXME
AsmOperand::Sym(_) => (),
});
if diverge {
self.result.standard_types.never.clone()
} else {
self.result.standard_types.unit.clone()
}
}
};
// use a new type variable if we got unknown here
let ty = self.insert_type_vars_shallow(ty);
self.write_expr_ty(tgt_expr, ty.clone());
if self.resolve_ty_shallow(&ty).is_never()
&& self.expr_guaranteed_to_constitute_read_for_never(tgt_expr, is_read)
{
// Any expression that produces a value of type `!` must have diverged
self.diverges = Diverges::Always;
}
ty
}
fn infer_expr_path(&mut self, path: &Path, id: ExprOrPatId, scope_id: ExprId) -> Ty {
let g = self.resolver.update_to_inner_scope(self.db, self.owner, scope_id);
let ty = match self.infer_path(path, id) {
Some(ty) => ty,
None => {
if path.mod_path().is_some_and(|mod_path| mod_path.is_ident() || mod_path.is_self())
{
self.push_diagnostic(InferenceDiagnostic::UnresolvedIdent { id });
}
self.err_ty()
}
};
self.resolver.reset_to_guard(g);
ty
}
fn infer_async_block(
&mut self,
tgt_expr: ExprId,
id: &Option<BlockId>,
statements: &[Statement],
tail: &Option<ExprId>,
) -> Ty {
let ret_ty = self.table.new_type_var();
let prev_diverges = mem::replace(&mut self.diverges, Diverges::Maybe);
let prev_ret_ty = mem::replace(&mut self.return_ty, ret_ty.clone());
let prev_ret_coercion = self.return_coercion.replace(CoerceMany::new(ret_ty.clone()));
// FIXME: We should handle async blocks like we handle closures
let expected = &Expectation::has_type(ret_ty);
let (_, inner_ty) = self.with_breakable_ctx(BreakableKind::Border, None, None, |this| {
let ty = this.infer_block(tgt_expr, *id, statements, *tail, None, expected);
if let Some(target) = expected.only_has_type(&mut this.table) {
match this.coerce(Some(tgt_expr), &ty, &target, CoerceNever::Yes) {
Ok(res) => res,
Err(_) => {
this.result.type_mismatches.insert(
tgt_expr.into(),
TypeMismatch { expected: target.clone(), actual: ty.clone() },
);
target
}
}
} else {
ty
}
});
self.diverges = prev_diverges;
self.return_ty = prev_ret_ty;
self.return_coercion = prev_ret_coercion;
self.lower_async_block_type_impl_trait(inner_ty, tgt_expr)
}
pub(crate) fn lower_async_block_type_impl_trait(
&mut self,
inner_ty: Ty,
tgt_expr: ExprId,
) -> Ty {
// Use the first type parameter as the output type of future.
// existential type AsyncBlockImplTrait<InnerType>: Future<Output = InnerType>
let impl_trait_id = crate::ImplTraitId::AsyncBlockTypeImplTrait(self.owner, tgt_expr);
let opaque_ty_id = self.db.intern_impl_trait_id(impl_trait_id).into();
TyKind::OpaqueType(opaque_ty_id, Substitution::from1(Interner, inner_ty)).intern(Interner)
}
pub(crate) fn write_fn_trait_method_resolution(
&mut self,
fn_x: FnTrait,
derefed_callee: &Ty,
adjustments: &mut Vec<Adjustment>,
callee_ty: &Ty,
params: &[Ty],
tgt_expr: ExprId,
) {
match fn_x {
FnTrait::FnOnce | FnTrait::AsyncFnOnce => (),
FnTrait::FnMut | FnTrait::AsyncFnMut => {
if let TyKind::Ref(Mutability::Mut, lt, inner) = derefed_callee.kind(Interner) {
if adjustments
.last()
.map(|it| matches!(it.kind, Adjust::Borrow(_)))
.unwrap_or(true)
{
// prefer reborrow to move
adjustments
.push(Adjustment { kind: Adjust::Deref(None), target: inner.clone() });
adjustments.push(Adjustment::borrow(
Mutability::Mut,
inner.clone(),
lt.clone(),
))
}
} else {
adjustments.push(Adjustment::borrow(
Mutability::Mut,
derefed_callee.clone(),
self.table.new_lifetime_var(),
));
}
}
FnTrait::Fn | FnTrait::AsyncFn => {
if !matches!(derefed_callee.kind(Interner), TyKind::Ref(Mutability::Not, _, _)) {
adjustments.push(Adjustment::borrow(
Mutability::Not,
derefed_callee.clone(),
self.table.new_lifetime_var(),
));
}
}
}
let Some(trait_) = fn_x.get_id(self.db, self.table.trait_env.krate) else {
return;
};
let trait_data = self.db.trait_items(trait_);
if let Some(func) = trait_data.method_by_name(&fn_x.method_name()) {
let subst = TyBuilder::subst_for_def(self.db, trait_, None)
.push(callee_ty.clone())
.push(TyBuilder::tuple_with(params.iter().cloned()))
.build();
self.write_method_resolution(tgt_expr, func, subst);
}
}
fn infer_expr_array(
&mut self,
array: &Array,
expected: &Expectation,
) -> chalk_ir::Ty<Interner> {
let elem_ty = match expected.to_option(&mut self.table).as_ref().map(|t| t.kind(Interner)) {
Some(TyKind::Array(st, _) | TyKind::Slice(st)) => st.clone(),
_ => self.table.new_type_var(),
};
let krate = self.resolver.krate();
let expected = Expectation::has_type(elem_ty.clone());
let (elem_ty, len) = match array {
Array::ElementList { elements, .. } if elements.is_empty() => {
(elem_ty, consteval::usize_const(self.db, Some(0), krate))
}
Array::ElementList { elements, .. } => {
let mut coerce = CoerceMany::new(elem_ty);
for &expr in elements.iter() {
let cur_elem_ty = self.infer_expr_inner(expr, &expected, ExprIsRead::Yes);
coerce.coerce(self, Some(expr), &cur_elem_ty, CoercionCause::Expr(expr));
}
(
coerce.complete(self),
consteval::usize_const(self.db, Some(elements.len() as u128), krate),
)
}
&Array::Repeat { initializer, repeat } => {
self.infer_expr_coerce(
initializer,
&Expectation::has_type(elem_ty.clone()),
ExprIsRead::Yes,
);
let usize = TyKind::Scalar(Scalar::Uint(UintTy::Usize)).intern(Interner);
match self.body[repeat] {
Expr::Underscore => {
self.write_expr_ty(repeat, usize);
}
_ => _ = self.infer_expr(repeat, &Expectation::HasType(usize), ExprIsRead::Yes),
}
(
elem_ty,
consteval::eval_to_const(
repeat,
ParamLoweringMode::Placeholder,
self,
DebruijnIndex::INNERMOST,
),
)
}
};
// Try to evaluate unevaluated constant, and insert variable if is not possible.
let len = self.table.insert_const_vars_shallow(len);
TyKind::Array(elem_ty, len).intern(Interner)
}
pub(super) fn infer_return(&mut self, expr: ExprId) {
let ret_ty = self
.return_coercion
.as_mut()
.expect("infer_return called outside function body")
.expected_ty();
let return_expr_ty =
self.infer_expr_inner(expr, &Expectation::HasType(ret_ty), ExprIsRead::Yes);
let mut coerce_many = self.return_coercion.take().unwrap();
coerce_many.coerce(self, Some(expr), &return_expr_ty, CoercionCause::Expr(expr));
self.return_coercion = Some(coerce_many);
}
fn infer_expr_return(&mut self, ret: ExprId, expr: Option<ExprId>) -> Ty {
match self.return_coercion {
Some(_) => {
if let Some(expr) = expr {
self.infer_return(expr);
} else {
let mut coerce = self.return_coercion.take().unwrap();
coerce.coerce_forced_unit(self, CoercionCause::Expr(ret));
self.return_coercion = Some(coerce);
}
}
None => {
// FIXME: diagnose return outside of function
if let Some(expr) = expr {
self.infer_expr_no_expect(expr, ExprIsRead::Yes);
}
}
}
self.result.standard_types.never.clone()
}
fn infer_expr_become(&mut self, expr: ExprId) -> Ty {
match &self.return_coercion {
Some(return_coercion) => {
let ret_ty = return_coercion.expected_ty();
let call_expr_ty = self.infer_expr_inner(
expr,
&Expectation::HasType(ret_ty.clone()),
ExprIsRead::Yes,
);
// NB: this should *not* coerce.
// tail calls don't support any coercions except lifetimes ones (like `&'static u8 -> &'a u8`).
self.unify(&call_expr_ty, &ret_ty);
}
None => {
// FIXME: diagnose `become` outside of functions
self.infer_expr_no_expect(expr, ExprIsRead::Yes);
}
}
self.result.standard_types.never.clone()
}
fn infer_expr_box(&mut self, inner_expr: ExprId, expected: &Expectation) -> Ty {
if let Some(box_id) = self.resolve_boxed_box() {
let table = &mut self.table;
let inner_exp = expected
.to_option(table)
.as_ref()
.and_then(|e| e.as_adt())
.filter(|(e_adt, _)| e_adt == &box_id)
.map(|(_, subts)| {
let g = subts.at(Interner, 0);
Expectation::rvalue_hint(self, Ty::clone(g.assert_ty_ref(Interner)))
})
.unwrap_or_else(Expectation::none);
let inner_ty = self.infer_expr_inner(inner_expr, &inner_exp, ExprIsRead::Yes);
TyBuilder::adt(self.db, box_id)
.push(inner_ty)
.fill_with_defaults(self.db, || self.table.new_type_var())
.build()
} else {
self.err_ty()
}
}
fn infer_overloadable_binop(
&mut self,
lhs: ExprId,
op: BinaryOp,
rhs: ExprId,
tgt_expr: ExprId,
) -> Ty {
let lhs_expectation = Expectation::none();
let is_read = if matches!(op, BinaryOp::Assignment { .. }) {
ExprIsRead::Yes
} else {
ExprIsRead::No
};
let lhs_ty = self.infer_expr(lhs, &lhs_expectation, is_read);
let rhs_ty = self.table.new_type_var();
let trait_func = lang_items_for_bin_op(op).and_then(|(name, lang_item)| {
let trait_id = self.resolve_lang_item(lang_item)?.as_trait()?;
let func = self.db.trait_items(trait_id).method_by_name(&name)?;
Some((trait_id, func))
});
let (trait_, func) = match trait_func {
Some(it) => it,
None => {
// HACK: `rhs_ty` is a general inference variable with no clue at all at this
// point. Passing `lhs_ty` as both operands just to check if `lhs_ty` is a builtin
// type applicable to `op`.
let ret_ty = if self.is_builtin_binop(&lhs_ty, &lhs_ty, op) {
// Assume both operands are builtin so we can continue inference. No guarantee
// on the correctness, rustc would complain as necessary lang items don't seem
// to exist anyway.
self.enforce_builtin_binop_types(&lhs_ty, &rhs_ty, op)
} else {
self.err_ty()
};
self.infer_expr_coerce(rhs, &Expectation::has_type(rhs_ty), ExprIsRead::Yes);
return ret_ty;
}
};
// HACK: We can use this substitution for the function because the function itself doesn't
// have its own generic parameters.
let subst = TyBuilder::subst_for_def(self.db, trait_, None);
if subst.remaining() != 2 {
return Ty::new(Interner, TyKind::Error);
}
let subst = subst.push(lhs_ty.clone()).push(rhs_ty.clone()).build();
self.write_method_resolution(tgt_expr, func, subst.clone());
let method_ty = self.db.value_ty(func.into()).unwrap().substitute(Interner, &subst);
self.register_obligations_for_call(&method_ty);
self.infer_expr_coerce(rhs, &Expectation::has_type(rhs_ty.clone()), ExprIsRead::Yes);
let ret_ty = match method_ty.callable_sig(self.db) {
Some(sig) => {
let p_left = &sig.params()[0];
if matches!(op, BinaryOp::CmpOp(..) | BinaryOp::Assignment { .. }) {
if let TyKind::Ref(mtbl, lt, _) = p_left.kind(Interner) {
self.write_expr_adj(
lhs,
vec![Adjustment {
kind: Adjust::Borrow(AutoBorrow::Ref(lt.clone(), *mtbl)),
target: p_left.clone(),
}],
);
}
}
let p_right = &sig.params()[1];
if matches!(op, BinaryOp::CmpOp(..)) {
if let TyKind::Ref(mtbl, lt, _) = p_right.kind(Interner) {
self.write_expr_adj(
rhs,
vec![Adjustment {
kind: Adjust::Borrow(AutoBorrow::Ref(lt.clone(), *mtbl)),
target: p_right.clone(),
}],
);
}
}
sig.ret().clone()
}
None => self.err_ty(),
};
let ret_ty = self.normalize_associated_types_in(ret_ty);
if self.is_builtin_binop(&lhs_ty, &rhs_ty, op) {
// use knowledge of built-in binary ops, which can sometimes help inference
let builtin_ret = self.enforce_builtin_binop_types(&lhs_ty, &rhs_ty, op);
self.unify(&builtin_ret, &ret_ty);
}
ret_ty
}
fn infer_block(
&mut self,
expr: ExprId,
block_id: Option<BlockId>,
statements: &[Statement],
tail: Option<ExprId>,
label: Option<LabelId>,
expected: &Expectation,
) -> Ty {
let coerce_ty = expected.coercion_target_type(&mut self.table);
let g = self.resolver.update_to_inner_scope(self.db, self.owner, expr);
let prev_env = block_id.map(|block_id| {
let prev_env = self.table.trait_env.clone();
TraitEnvironment::with_block(&mut self.table.trait_env, block_id);
prev_env
});
let (break_ty, ty) =
self.with_breakable_ctx(BreakableKind::Block, Some(coerce_ty), label, |this| {
for stmt in statements {
match stmt {
Statement::Let { pat, type_ref, initializer, else_branch } => {
let decl_ty = type_ref
.as_ref()
.map(|&tr| this.make_body_ty(tr))
.unwrap_or_else(|| this.table.new_type_var());
let ty = if let Some(expr) = initializer {
// If we have a subpattern that performs a read, we want to consider this
// to diverge for compatibility to support something like `let x: () = *never_ptr;`.
let target_is_read =
if this.pat_guaranteed_to_constitute_read_for_never(*pat) {
ExprIsRead::Yes
} else {
ExprIsRead::No
};
let ty = if contains_explicit_ref_binding(this.body, *pat) {
this.infer_expr(
*expr,
&Expectation::has_type(decl_ty.clone()),
target_is_read,
)
} else {
this.infer_expr_coerce(
*expr,
&Expectation::has_type(decl_ty.clone()),
target_is_read,
)
};
if type_ref.is_some() { decl_ty } else { ty }
} else {
decl_ty
};
let decl = DeclContext {
origin: DeclOrigin::LocalDecl { has_else: else_branch.is_some() },
};
this.infer_top_pat(*pat, &ty, Some(decl));
if let Some(expr) = else_branch {
let previous_diverges =
mem::replace(&mut this.diverges, Diverges::Maybe);
this.infer_expr_coerce(
*expr,
&Expectation::HasType(this.result.standard_types.never.clone()),
ExprIsRead::Yes,
);
this.diverges = previous_diverges;
}
}
&Statement::Expr { expr, has_semi } => {
if has_semi {
this.infer_expr(expr, &Expectation::none(), ExprIsRead::Yes);
} else {
this.infer_expr_coerce(
expr,
&Expectation::HasType(this.result.standard_types.unit.clone()),
ExprIsRead::Yes,
);
}
}
Statement::Item(_) => (),
}
}
// FIXME: This should make use of the breakable CoerceMany
if let Some(expr) = tail {
this.infer_expr_coerce(expr, expected, ExprIsRead::Yes)
} else {
// Citing rustc: if there is no explicit tail expression,
// that is typically equivalent to a tail expression
// of `()` -- except if the block diverges. In that
// case, there is no value supplied from the tail
// expression (assuming there are no other breaks,
// this implies that the type of the block will be
// `!`).
if this.diverges.is_always() {
// we don't even make an attempt at coercion
this.table.new_maybe_never_var()
} else if let Some(t) = expected.only_has_type(&mut this.table) {
let coerce_never = if this
.expr_guaranteed_to_constitute_read_for_never(expr, ExprIsRead::Yes)
{
CoerceNever::Yes
} else {
CoerceNever::No
};
if this
.coerce(
Some(expr),
&this.result.standard_types.unit.clone(),
&t,
coerce_never,
)
.is_err()
{
this.result.type_mismatches.insert(
expr.into(),
TypeMismatch {
expected: t.clone(),
actual: this.result.standard_types.unit.clone(),
},
);
}
t
} else {
this.result.standard_types.unit.clone()
}
}
});
self.resolver.reset_to_guard(g);
if let Some(prev_env) = prev_env {
self.table.trait_env = prev_env;
}
break_ty.unwrap_or(ty)
}
fn lookup_field(
&mut self,
receiver_ty: &Ty,
name: &Name,
) -> Option<(Ty, Either<FieldId, TupleFieldId>, Vec<Adjustment>, bool)> {
let mut autoderef = Autoderef::new(&mut self.table, receiver_ty.clone(), false, false);
let mut private_field = None;
let res = autoderef.by_ref().find_map(|(derefed_ty, _)| {
let (field_id, parameters) = match derefed_ty.kind(Interner) {
TyKind::Tuple(_, substs) => {
return name.as_tuple_index().and_then(|idx| {
substs
.as_slice(Interner)
.get(idx)
.map(|a| a.assert_ty_ref(Interner))
.cloned()
.map(|ty| {
(
Either::Right(TupleFieldId {
tuple: TupleId(
self.tuple_field_accesses_rev
.insert_full(substs.clone())
.0
as u32,
),
index: idx as u32,
}),
ty,
)
})
});
}
&TyKind::Adt(AdtId(hir_def::AdtId::StructId(s)), ref parameters) => {
let local_id = self.db.variant_fields(s.into()).field(name)?;
let field = FieldId { parent: s.into(), local_id };
(field, parameters.clone())
}
&TyKind::Adt(AdtId(hir_def::AdtId::UnionId(u)), ref parameters) => {
let local_id = self.db.variant_fields(u.into()).field(name)?;
let field = FieldId { parent: u.into(), local_id };
(field, parameters.clone())
}
_ => return None,
};
let is_visible = self.db.field_visibilities(field_id.parent)[field_id.local_id]
.is_visible_from(self.db, self.resolver.module());
if !is_visible {
if private_field.is_none() {
private_field = Some((field_id, parameters));
}
return None;
}
let ty = self.db.field_types(field_id.parent)[field_id.local_id]
.clone()
.substitute(Interner, &parameters);
Some((Either::Left(field_id), ty))
});
Some(match res {
Some((field_id, ty)) => {
let adjustments = auto_deref_adjust_steps(&autoderef);
let ty = self.insert_type_vars(ty);
let ty = self.normalize_associated_types_in(ty);
(ty, field_id, adjustments, true)
}
None => {
let (field_id, subst) = private_field?;
let adjustments = auto_deref_adjust_steps(&autoderef);
let ty = self.db.field_types(field_id.parent)[field_id.local_id]
.clone()
.substitute(Interner, &subst);
let ty = self.insert_type_vars(ty);
let ty = self.normalize_associated_types_in(ty);
(ty, Either::Left(field_id), adjustments, false)
}
})
}
fn infer_field_access(
&mut self,
tgt_expr: ExprId,
receiver: ExprId,
name: &Name,
expected: &Expectation,
) -> Ty {
// Field projections don't constitute reads.
let receiver_ty = self.infer_expr_inner(receiver, &Expectation::none(), ExprIsRead::No);
if name.is_missing() {
// Bail out early, don't even try to look up field. Also, we don't issue an unresolved
// field diagnostic because this is a syntax error rather than a semantic error.
return self.err_ty();
}
match self.lookup_field(&receiver_ty, name) {
Some((ty, field_id, adjustments, is_public)) => {
self.write_expr_adj(receiver, adjustments);
self.result.field_resolutions.insert(tgt_expr, field_id);
if !is_public {
if let Either::Left(field) = field_id {
// FIXME: Merge this diagnostic into UnresolvedField?
self.push_diagnostic(InferenceDiagnostic::PrivateField {
expr: tgt_expr,
field,
});
}
}
ty
}
None => {
// no field found, lets attempt to resolve it like a function so that IDE things
// work out while people are typing
let canonicalized_receiver = self.canonicalize(receiver_ty.clone());
let resolved = method_resolution::lookup_method(
self.db,
&canonicalized_receiver,
self.table.trait_env.clone(),
self.get_traits_in_scope().as_ref().left_or_else(|&it| it),
VisibleFromModule::Filter(self.resolver.module()),
name,
);
self.push_diagnostic(InferenceDiagnostic::UnresolvedField {
expr: tgt_expr,
receiver: receiver_ty.clone(),
name: name.clone(),
method_with_same_name_exists: resolved.is_some(),
});
match resolved {
Some((adjust, func, _)) => {
let (ty, adjustments) = adjust.apply(&mut self.table, receiver_ty);
let substs = self.substs_for_method_call(tgt_expr, func.into(), None);
self.write_expr_adj(receiver, adjustments);
self.write_method_resolution(tgt_expr, func, substs.clone());
self.check_method_call(
tgt_expr,
&[],
self.db.value_ty(func.into()).unwrap(),
substs,
ty,
expected,
)
}
None => self.err_ty(),
}
}
}
}
fn infer_call(
&mut self,
tgt_expr: ExprId,
callee: ExprId,
args: &[ExprId],
expected: &Expectation,
) -> Ty {
let callee_ty = self.infer_expr(callee, &Expectation::none(), ExprIsRead::Yes);
let mut derefs = Autoderef::new(&mut self.table, callee_ty.clone(), false, true);
let (res, derefed_callee) = loop {
let Some((callee_deref_ty, _)) = derefs.next() else {
break (None, callee_ty.clone());
};
if let Some(res) = derefs.table.callable_sig(&callee_deref_ty, args.len()) {
break (Some(res), callee_deref_ty);
}
};
// if the function is unresolved, we use is_varargs=true to
// suppress the arg count diagnostic here
let is_varargs =
derefed_callee.callable_sig(self.db).is_some_and(|sig| sig.is_varargs) || res.is_none();
let (param_tys, ret_ty) = match res {
Some((func, params, ret_ty)) => {
let mut adjustments = auto_deref_adjust_steps(&derefs);
if let TyKind::Closure(c, _) =
self.table.resolve_completely(callee_ty.clone()).kind(Interner)
{
self.add_current_closure_dependency(*c);
self.deferred_closures.entry(*c).or_default().push((
derefed_callee.clone(),
callee_ty.clone(),
params.clone(),
tgt_expr,
));
}
if let Some(fn_x) = func {
self.write_fn_trait_method_resolution(
fn_x,
&derefed_callee,
&mut adjustments,
&callee_ty,
&params,
tgt_expr,
);
}
self.write_expr_adj(callee, adjustments);
(params, ret_ty)
}
None => {
self.push_diagnostic(InferenceDiagnostic::ExpectedFunction {
call_expr: tgt_expr,
found: callee_ty.clone(),
});
(Vec::new(), self.err_ty())
}
};
let indices_to_skip = self.check_legacy_const_generics(derefed_callee, args);
self.check_call(
tgt_expr,
args,
callee_ty,
&param_tys,
ret_ty,
&indices_to_skip,
is_varargs,
expected,
)
}
fn check_call(
&mut self,
tgt_expr: ExprId,
args: &[ExprId],
callee_ty: Ty,
param_tys: &[Ty],
ret_ty: Ty,
indices_to_skip: &[u32],
is_varargs: bool,
expected: &Expectation,
) -> Ty {
self.register_obligations_for_call(&callee_ty);
let expected_inputs = self.expected_inputs_for_expected_output(
expected,
ret_ty.clone(),
param_tys.to_owned(),
);
self.check_call_arguments(
tgt_expr,
args,
&expected_inputs,
param_tys,
indices_to_skip,
is_varargs,
);
self.normalize_associated_types_in(ret_ty)
}
fn infer_method_call(
&mut self,
tgt_expr: ExprId,
receiver: ExprId,
args: &[ExprId],
method_name: &Name,
generic_args: Option<&GenericArgs>,
expected: &Expectation,
) -> Ty {
let receiver_ty = self.infer_expr_inner(receiver, &Expectation::none(), ExprIsRead::Yes);
let canonicalized_receiver = self.canonicalize(receiver_ty.clone());
let resolved = method_resolution::lookup_method(
self.db,
&canonicalized_receiver,
self.table.trait_env.clone(),
self.get_traits_in_scope().as_ref().left_or_else(|&it| it),
VisibleFromModule::Filter(self.resolver.module()),
method_name,
);
match resolved {
Some((adjust, func, visible)) => {
if !visible {
self.push_diagnostic(InferenceDiagnostic::PrivateAssocItem {
id: tgt_expr.into(),
item: func.into(),
})
}
let (ty, adjustments) = adjust.apply(&mut self.table, receiver_ty);
self.write_expr_adj(receiver, adjustments);
let substs = self.substs_for_method_call(tgt_expr, func.into(), generic_args);
self.write_method_resolution(tgt_expr, func, substs.clone());
self.check_method_call(
tgt_expr,
args,
self.db.value_ty(func.into()).expect("we have a function def"),
substs,
ty,
expected,
)
}
// Failed to resolve, report diagnostic and try to resolve as call to field access or
// assoc function
None => {
let field_with_same_name_exists = match self.lookup_field(&receiver_ty, method_name)
{
Some((ty, field_id, adjustments, _public)) => {
self.write_expr_adj(receiver, adjustments);
self.result.field_resolutions.insert(tgt_expr, field_id);
Some(ty)
}
None => None,
};
let assoc_func_with_same_name = method_resolution::iterate_method_candidates(
&canonicalized_receiver,
self.db,
self.table.trait_env.clone(),
self.get_traits_in_scope().as_ref().left_or_else(|&it| it),
VisibleFromModule::Filter(self.resolver.module()),
Some(method_name),
method_resolution::LookupMode::Path,
|_ty, item, visible| match item {
hir_def::AssocItemId::FunctionId(function_id) if visible => {
Some(function_id)
}
_ => None,
},
);
self.push_diagnostic(InferenceDiagnostic::UnresolvedMethodCall {
expr: tgt_expr,
receiver: receiver_ty.clone(),
name: method_name.clone(),
field_with_same_name: field_with_same_name_exists.clone(),
assoc_func_with_same_name,
});
let recovered = match assoc_func_with_same_name {
Some(f) => {
let substs = self.substs_for_method_call(tgt_expr, f.into(), generic_args);
let f = self
.db
.value_ty(f.into())
.expect("we have a function def")
.substitute(Interner, &substs);
let sig = f.callable_sig(self.db).expect("we have a function def");
Some((f, sig, true))
}
None => field_with_same_name_exists.and_then(|field_ty| {
let callable_sig = field_ty.callable_sig(self.db)?;
Some((field_ty, callable_sig, false))
}),
};
match recovered {
Some((callee_ty, sig, strip_first)) => self.check_call(
tgt_expr,
args,
callee_ty,
sig.params().get(strip_first as usize..).unwrap_or(&[]),
sig.ret().clone(),
&[],
true,
expected,
),
None => {
self.check_call_arguments(tgt_expr, args, &[], &[], &[], true);
self.err_ty()
}
}
}
}
}
fn check_method_call(
&mut self,
tgt_expr: ExprId,
args: &[ExprId],
method_ty: Binders<Ty>,
substs: Substitution,
receiver_ty: Ty,
expected: &Expectation,
) -> Ty {
let method_ty = method_ty.substitute(Interner, &substs);
self.register_obligations_for_call(&method_ty);
let ((formal_receiver_ty, param_tys), ret_ty, is_varargs) =
match method_ty.callable_sig(self.db) {
Some(sig) => (
if !sig.params().is_empty() {
(sig.params()[0].clone(), sig.params()[1..].to_vec())
} else {
(self.err_ty(), Vec::new())
},
sig.ret().clone(),
sig.is_varargs,
),
None => ((self.err_ty(), Vec::new()), self.err_ty(), true),
};
self.unify(&formal_receiver_ty, &receiver_ty);
let expected_inputs =
self.expected_inputs_for_expected_output(expected, ret_ty.clone(), param_tys.clone());
self.check_call_arguments(tgt_expr, args, &expected_inputs, &param_tys, &[], is_varargs);
self.normalize_associated_types_in(ret_ty)
}
fn expected_inputs_for_expected_output(
&mut self,
expected_output: &Expectation,
output: Ty,
inputs: Vec<Ty>,
) -> Vec<Ty> {
if let Some(expected_ty) = expected_output.only_has_type(&mut self.table) {
self.table.fudge_inference(|table| {
if table.try_unify(&expected_ty, &output).is_ok() {
table.resolve_with_fallback(inputs, &|var, kind, _, _| match kind {
chalk_ir::VariableKind::Ty(tk) => var.to_ty(Interner, tk).cast(Interner),
chalk_ir::VariableKind::Lifetime => {
var.to_lifetime(Interner).cast(Interner)
}
chalk_ir::VariableKind::Const(ty) => {
var.to_const(Interner, ty).cast(Interner)
}
})
} else {
Vec::new()
}
})
} else {
Vec::new()
}
}
fn check_call_arguments(
&mut self,
expr: ExprId,
args: &[ExprId],
expected_inputs: &[Ty],
param_tys: &[Ty],
skip_indices: &[u32],
ignore_arg_param_mismatch: bool,
) {
let arg_count_mismatch =
!ignore_arg_param_mismatch && args.len() != param_tys.len() + skip_indices.len();
if arg_count_mismatch {
self.push_diagnostic(InferenceDiagnostic::MismatchedArgCount {
call_expr: expr,
expected: param_tys.len() + skip_indices.len(),
found: args.len(),
});
};
// Quoting https://github.com/rust-lang/rust/blob/6ef275e6c3cb1384ec78128eceeb4963ff788dca/src/librustc_typeck/check/mod.rs#L3325 --
// We do this in a pretty awful way: first we type-check any arguments
// that are not closures, then we type-check the closures. This is so
// that we have more information about the types of arguments when we
// type-check the functions. This isn't really the right way to do this.
for check_closures in [false, true] {
let mut skip_indices = skip_indices.iter().copied().fuse().peekable();
let param_iter = param_tys.iter().cloned().chain(repeat(self.err_ty()));
let expected_iter = expected_inputs
.iter()
.cloned()
.chain(param_iter.clone().skip(expected_inputs.len()));
for (idx, ((&arg, param_ty), expected_ty)) in
args.iter().zip(param_iter).zip(expected_iter).enumerate()
{
let is_closure = matches!(&self.body[arg], Expr::Closure { .. });
if is_closure != check_closures {
continue;
}
while skip_indices.peek().is_some_and(|&i| i < idx as u32) {
skip_indices.next();
}
if skip_indices.peek().copied() == Some(idx as u32) {
continue;
}
// the difference between param_ty and expected here is that
// expected is the parameter when the expected *return* type is
// taken into account. So in `let _: &[i32] = identity(&[1, 2])`
// the expected type is already `&[i32]`, whereas param_ty is
// still an unbound type variable. We don't always want to force
// the parameter to coerce to the expected type (for example in
// `coerce_unsize_expected_type_4`).
let param_ty = self.normalize_associated_types_in(param_ty);
let expected_ty = self.normalize_associated_types_in(expected_ty);
let expected = Expectation::rvalue_hint(self, expected_ty);
// infer with the expected type we have...
let ty = self.infer_expr_inner(arg, &expected, ExprIsRead::Yes);
// then coerce to either the expected type or just the formal parameter type
let coercion_target = if let Some(ty) = expected.only_has_type(&mut self.table) {
// if we are coercing to the expectation, unify with the
// formal parameter type to connect everything
self.unify(&ty, &param_ty);
ty
} else {
param_ty
};
// The function signature may contain some unknown types, so we need to insert
// type vars here to avoid type mismatch false positive.
let coercion_target = self.insert_type_vars(coercion_target);
// Any expression that produces a value of type `!` must have diverged,
// unless it's a place expression that isn't being read from, in which case
// diverging would be unsound since we may never actually read the `!`.
// e.g. `let _ = *never_ptr;` with `never_ptr: *const !`.
let coerce_never =
if self.expr_guaranteed_to_constitute_read_for_never(arg, ExprIsRead::Yes) {
CoerceNever::Yes
} else {
CoerceNever::No
};
if self.coerce(Some(arg), &ty, &coercion_target, coerce_never).is_err()
&& !arg_count_mismatch
{
self.result.type_mismatches.insert(
arg.into(),
TypeMismatch { expected: coercion_target, actual: ty.clone() },
);
}
}
}
}
fn substs_for_method_call(
&mut self,
expr: ExprId,
def: GenericDefId,
generic_args: Option<&GenericArgs>,
) -> Substitution {
struct LowererCtx<'a, 'b> {
ctx: &'a mut InferenceContext<'b>,
expr: ExprId,
}
impl GenericArgsLowerer for LowererCtx<'_, '_> {
fn report_len_mismatch(
&mut self,
def: GenericDefId,
provided_count: u32,
expected_count: u32,
kind: IncorrectGenericsLenKind,
) {
self.ctx.push_diagnostic(InferenceDiagnostic::MethodCallIncorrectGenericsLen {
expr: self.expr,
provided_count,
expected_count,
kind,
def,
});
}
fn report_arg_mismatch(
&mut self,
param_id: GenericParamId,
arg_idx: u32,
has_self_arg: bool,
) {
self.ctx.push_diagnostic(InferenceDiagnostic::MethodCallIncorrectGenericsOrder {
expr: self.expr,
param_id,
arg_idx,
has_self_arg,
});
}
fn provided_kind(
&mut self,
param_id: GenericParamId,
param: GenericParamDataRef<'_>,
arg: &GenericArg,
) -> crate::GenericArg {
match (param, arg) {
(GenericParamDataRef::LifetimeParamData(_), GenericArg::Lifetime(lifetime)) => {
self.ctx.make_body_lifetime(lifetime).cast(Interner)
}
(GenericParamDataRef::TypeParamData(_), GenericArg::Type(type_ref)) => {
self.ctx.make_body_ty(*type_ref).cast(Interner)
}
(GenericParamDataRef::ConstParamData(_), GenericArg::Const(konst)) => {
let GenericParamId::ConstParamId(const_id) = param_id else {
unreachable!("non-const param ID for const param");
};
let const_ty = self.ctx.db.const_param_ty(const_id);
self.ctx.make_body_const(*konst, const_ty).cast(Interner)
}
_ => unreachable!("unmatching param kinds were passed to `provided_kind()`"),
}
}
fn provided_type_like_const(
&mut self,
const_ty: Ty,
arg: TypeLikeConst<'_>,
) -> crate::Const {
match arg {
TypeLikeConst::Path(path) => self.ctx.make_path_as_body_const(path, const_ty),
TypeLikeConst::Infer => self.ctx.table.new_const_var(const_ty),
}
}
fn inferred_kind(
&mut self,
_def: GenericDefId,
param_id: GenericParamId,
_param: GenericParamDataRef<'_>,
_infer_args: bool,
_preceding_args: &[crate::GenericArg],
) -> crate::GenericArg {
// Always create an inference var, even when `infer_args == false`. This helps with diagnostics,
// and I think it's also required in the presence of `impl Trait` (that must be inferred).
match param_id {
GenericParamId::TypeParamId(_) => self.ctx.table.new_type_var().cast(Interner),
GenericParamId::ConstParamId(const_id) => self
.ctx
.table
.new_const_var(self.ctx.db.const_param_ty(const_id))
.cast(Interner),
GenericParamId::LifetimeParamId(_) => {
self.ctx.table.new_lifetime_var().cast(Interner)
}
}
}
fn parent_arg(&mut self, param_id: GenericParamId) -> crate::GenericArg {
match param_id {
GenericParamId::TypeParamId(_) => self.ctx.table.new_type_var().cast(Interner),
GenericParamId::ConstParamId(const_id) => self
.ctx
.table
.new_const_var(self.ctx.db.const_param_ty(const_id))
.cast(Interner),
GenericParamId::LifetimeParamId(_) => {
self.ctx.table.new_lifetime_var().cast(Interner)
}
}
}
}
substs_from_args_and_bindings(
self.db,
self.body,
generic_args,
def,
true,
GenericArgsPosition::MethodCall,
None,
&mut LowererCtx { ctx: self, expr },
)
}
fn register_obligations_for_call(&mut self, callable_ty: &Ty) {
let callable_ty = self.resolve_ty_shallow(callable_ty);
if let TyKind::FnDef(fn_def, parameters) = callable_ty.kind(Interner) {
let def: CallableDefId = from_chalk(self.db, *fn_def);
let generic_predicates =
self.db.generic_predicates(GenericDefId::from_callable(self.db, def));
for predicate in generic_predicates.iter() {
let (predicate, binders) = predicate
.clone()
.substitute(Interner, parameters)
.into_value_and_skipped_binders();
always!(binders.len(Interner) == 0); // quantified where clauses not yet handled
self.push_obligation(predicate.cast(Interner));
}
// add obligation for trait implementation, if this is a trait method
match def {
CallableDefId::FunctionId(f) => {
if let ItemContainerId::TraitId(trait_) = f.lookup(self.db).container {
// construct a TraitRef
let trait_params_len = generics(self.db, trait_.into()).len();
let substs = Substitution::from_iter(
Interner,
// The generic parameters for the trait come after those for the
// function.
&parameters.as_slice(Interner)[..trait_params_len],
);
self.push_obligation(
TraitRef { trait_id: to_chalk_trait_id(trait_), substitution: substs }
.cast(Interner),
);
}
}
CallableDefId::StructId(_) | CallableDefId::EnumVariantId(_) => {}
}
}
}
/// Returns the argument indices to skip.
fn check_legacy_const_generics(&mut self, callee: Ty, args: &[ExprId]) -> Box<[u32]> {
let (func, subst) = match callee.kind(Interner) {
TyKind::FnDef(fn_id, subst) => {
let callable = CallableDefId::from_chalk(self.db, *fn_id);
let func = match callable {
CallableDefId::FunctionId(f) => f,
_ => return Default::default(),
};
(func, subst)
}
_ => return Default::default(),
};
let data = self.db.function_signature(func);
let Some(legacy_const_generics_indices) = &data.legacy_const_generics_indices else {
return Default::default();
};
// only use legacy const generics if the param count matches with them
if data.params.len() + legacy_const_generics_indices.len() != args.len() {
if args.len() <= data.params.len() {
return Default::default();
} else {
// there are more parameters than there should be without legacy
// const params; use them
let mut indices = legacy_const_generics_indices.as_ref().clone();
indices.sort();
return indices;
}
}
// check legacy const parameters
for (subst_idx, arg_idx) in legacy_const_generics_indices.iter().copied().enumerate() {
let arg = match subst.at(Interner, subst_idx).constant(Interner) {
Some(c) => c,
None => continue, // not a const parameter?
};
if arg_idx >= args.len() as u32 {
continue;
}
let _ty = arg.data(Interner).ty.clone();
let expected = Expectation::none(); // FIXME use actual const ty, when that is lowered correctly
self.infer_expr(args[arg_idx as usize], &expected, ExprIsRead::Yes);
// FIXME: evaluate and unify with the const
}
let mut indices = legacy_const_generics_indices.as_ref().clone();
indices.sort();
indices
}
/// Dereferences a single level of immutable referencing.
fn deref_ty_if_possible(&mut self, ty: &Ty) -> Ty {
let ty = self.resolve_ty_shallow(ty);
match ty.kind(Interner) {
TyKind::Ref(Mutability::Not, _, inner) => self.resolve_ty_shallow(inner),
_ => ty,
}
}
/// Enforces expectations on lhs type and rhs type depending on the operator and returns the
/// output type of the binary op.
fn enforce_builtin_binop_types(&mut self, lhs: &Ty, rhs: &Ty, op: BinaryOp) -> Ty {
// Special-case a single layer of referencing, so that things like `5.0 + &6.0f32` work (See rust-lang/rust#57447).
let lhs = self.deref_ty_if_possible(lhs);
let rhs = self.deref_ty_if_possible(rhs);
let (op, is_assign) = match op {
BinaryOp::Assignment { op: Some(inner) } => (BinaryOp::ArithOp(inner), true),
_ => (op, false),
};
let output_ty = match op {
BinaryOp::LogicOp(_) => {
let bool_ = self.result.standard_types.bool_.clone();
self.unify(&lhs, &bool_);
self.unify(&rhs, &bool_);
bool_
}
BinaryOp::ArithOp(ArithOp::Shl | ArithOp::Shr) => {
// result type is same as LHS always
lhs
}
BinaryOp::ArithOp(_) => {
// LHS, RHS, and result will have the same type
self.unify(&lhs, &rhs);
lhs
}
BinaryOp::CmpOp(_) => {
// LHS and RHS will have the same type
self.unify(&lhs, &rhs);
self.result.standard_types.bool_.clone()
}
BinaryOp::Assignment { op: None } => {
stdx::never!("Simple assignment operator is not binary op.");
lhs
}
BinaryOp::Assignment { .. } => unreachable!("handled above"),
};
if is_assign { self.result.standard_types.unit.clone() } else { output_ty }
}
fn is_builtin_binop(&mut self, lhs: &Ty, rhs: &Ty, op: BinaryOp) -> bool {
// Special-case a single layer of referencing, so that things like `5.0 + &6.0f32` work (See rust-lang/rust#57447).
let lhs = self.deref_ty_if_possible(lhs);
let rhs = self.deref_ty_if_possible(rhs);
let op = match op {
BinaryOp::Assignment { op: Some(inner) } => BinaryOp::ArithOp(inner),
_ => op,
};
match op {
BinaryOp::LogicOp(_) => true,
BinaryOp::ArithOp(ArithOp::Shl | ArithOp::Shr) => {
lhs.is_integral() && rhs.is_integral()
}
BinaryOp::ArithOp(
ArithOp::Add | ArithOp::Sub | ArithOp::Mul | ArithOp::Div | ArithOp::Rem,
) => {
lhs.is_integral() && rhs.is_integral()
|| lhs.is_floating_point() && rhs.is_floating_point()
}
BinaryOp::ArithOp(ArithOp::BitAnd | ArithOp::BitOr | ArithOp::BitXor) => {
lhs.is_integral() && rhs.is_integral()
|| lhs.is_floating_point() && rhs.is_floating_point()
|| matches!(
(lhs.kind(Interner), rhs.kind(Interner)),
(TyKind::Scalar(Scalar::Bool), TyKind::Scalar(Scalar::Bool))
)
}
BinaryOp::CmpOp(_) => {
let is_scalar = |kind| {
matches!(
kind,
&TyKind::Scalar(_)
| TyKind::FnDef(..)
| TyKind::Function(_)
| TyKind::Raw(..)
| TyKind::InferenceVar(
_,
TyVariableKind::Integer | TyVariableKind::Float
)
)
};
is_scalar(lhs.kind(Interner)) && is_scalar(rhs.kind(Interner))
}
BinaryOp::Assignment { op: None } => {
stdx::never!("Simple assignment operator is not binary op.");
false
}
BinaryOp::Assignment { .. } => unreachable!("handled above"),
}
}
pub(super) fn with_breakable_ctx<T>(
&mut self,
kind: BreakableKind,
ty: Option<Ty>,
label: Option<LabelId>,
cb: impl FnOnce(&mut Self) -> T,
) -> (Option<Ty>, T) {
self.breakables.push({
BreakableContext { kind, may_break: false, coerce: ty.map(CoerceMany::new), label }
});
let res = cb(self);
let ctx = self.breakables.pop().expect("breakable stack broken");
(if ctx.may_break { ctx.coerce.map(|ctx| ctx.complete(self)) } else { None }, res)
}
}
Reference in New Issue View Git Blame Copy Permalink