Impl HirDisplay for SelfParam

crates/hir/src/display.rs

@@ -8,7 +8,6 @@ use hir_def::{
     type_ref::{TypeBound, TypeRef},
     AdtId, GenericDefId,
 };
-use hir_expand::name;
 use hir_ty::{
     display::{
         write_bounds_like_dyn_trait_with_prefix, write_visibility, HirDisplay, HirDisplayError,
@@ -19,8 +18,9 @@ use hir_ty::{
 
 use crate::{
     Adt, AsAssocItem, AssocItemContainer, Const, ConstParam, Enum, ExternCrateDecl, Field,
-    Function, GenericParam, HasCrate, HasVisibility, LifetimeParam, Macro, Module, Static, Struct,
+    Function, GenericParam, HasCrate, HasVisibility, LifetimeParam, Macro, Module, SelfParam,
-    Trait, TraitAlias, TyBuilder, Type, TypeAlias, TypeOrConstParam, TypeParam, Union, Variant,
+    Static, Struct, Trait, TraitAlias, TyBuilder, Type, TypeAlias, TypeOrConstParam, TypeParam,
+    Union, Variant,
 };
 
 impl HirDisplay for Function {
@@ -57,37 +57,21 @@ impl HirDisplay for Function {
 
         f.write_char('(')?;
 
-        let write_self_param = |ty: &TypeRef, f: &mut HirFormatter<'_>| match ty {
-            TypeRef::Path(p) if p.is_self_type() => f.write_str("self"),
-            TypeRef::Reference(inner, lifetime, mut_) if matches!(&**inner, TypeRef::Path(p) if p.is_self_type()) =>
-            {
-                f.write_char('&')?;
-                if let Some(lifetime) = lifetime {
-                    write!(f, "{} ", lifetime.name.display(f.db.upcast()))?;
-                }
-                if let hir_def::type_ref::Mutability::Mut = mut_ {
-                    f.write_str("mut ")?;
-                }
-                f.write_str("self")
-            }
-            _ => {
-                f.write_str("self: ")?;
-                ty.hir_fmt(f)
-            }
-        };
-
         let mut first = true;
+        let mut skip_self = 0;
+        if let Some(self_param) = self.self_param(db) {
+            self_param.hir_fmt(f)?;
+            first = false;
+            skip_self = 1;
+        }
+
         // FIXME: Use resolved `param.ty` once we no longer discard lifetimes
-        for (type_ref, param) in data.params.iter().zip(self.assoc_fn_params(db)) {
+        for (type_ref, param) in data.params.iter().zip(self.assoc_fn_params(db)).skip(skip_self) {
             let local = param.as_local(db).map(|it| it.name(db));
             if !first {
                 f.write_str(", ")?;
             } else {
                 first = false;
-                if local == Some(name!(self)) {
-                    write_self_param(type_ref, f)?;
-                    continue;
-                }
             }
             match local {
                 Some(name) => write!(f, "{}: ", name.display(f.db.upcast()))?,
@@ -137,6 +121,31 @@ impl HirDisplay for Function {
     }
 }
 
+impl HirDisplay for SelfParam {
+    fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
+        let data = f.db.function_data(self.func);
+        let param = data.params.first().unwrap();
+        match &**param {
+            TypeRef::Path(p) if p.is_self_type() => f.write_str("self"),
+            TypeRef::Reference(inner, lifetime, mut_) if matches!(&**inner, TypeRef::Path(p) if p.is_self_type()) =>
+            {
+                f.write_char('&')?;
+                if let Some(lifetime) = lifetime {
+                    write!(f, "{} ", lifetime.name.display(f.db.upcast()))?;
+                }
+                if let hir_def::type_ref::Mutability::Mut = mut_ {
+                    f.write_str("mut ")?;
+                }
+                f.write_str("self")
+            }
+            ty => {
+                f.write_str("self: ")?;
+                ty.hir_fmt(f)
+            }
+        }
+    }
+}
+
 impl HirDisplay for Adt {
     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
         match self {

crates/hir/src/lib.rs

@@ -2096,14 +2096,6 @@ impl SelfParam {
             .unwrap_or(Access::Owned)
     }
 
-    pub fn display(self, db: &dyn HirDatabase) -> &'static str {
-        match self.access(db) {
-            Access::Shared => "&self",
-            Access::Exclusive => "&mut self",
-            Access::Owned => "self",
-        }
-    }
-
     pub fn source(&self, db: &dyn HirDatabase) -> Option<InFile<ast::SelfParam>> {
         let InFile { file_id, value } = Function::from(self.func).source(db)?;
         value