Make impl HirDisplay for TraitRef provide just the trait type

Author: mgsloan

src/tools/rust-analyzer/crates/hir-ty/src/display.rs

@@ -474,7 +474,9 @@ impl HirDisplay for ProjectionTy {
 
         let trait_ref = self.trait_ref(f.db);
         write!(f, "<")?;
-        fmt_trait_ref(f, &trait_ref, TraitRefFormat::SelfAsTrait)?;
+        trait_ref.self_type_parameter(Interner).hir_fmt(f)?;
+        write!(f, " as ")?;
+        trait_ref.hir_fmt(f)?;
         write!(
             f,
             ">::{}",
@@ -1775,50 +1777,14 @@ fn write_bounds_like_dyn_trait(
     Ok(())
 }
 
-#[derive(Clone, Copy)]
-pub enum TraitRefFormat {
-    SelfAsTrait,
-    SelfImplementsTrait,
-    OnlyTrait,
-}
-
-fn fmt_trait_ref(
-    f: &mut HirFormatter<'_>,
-    tr: &TraitRef,
-    format: TraitRefFormat,
-) -> Result<(), HirDisplayError> {
-    if f.should_truncate() {
-        return write!(f, "{TYPE_HINT_TRUNCATION}");
-    }
-
-    match format {
-        TraitRefFormat::SelfAsTrait => {
-            tr.self_type_parameter(Interner).hir_fmt(f)?;
-            write!(f, " as ")?;
-        }
-        TraitRefFormat::SelfImplementsTrait => {
-            tr.self_type_parameter(Interner).hir_fmt(f)?;
-            write!(f, ": ")?;
-        }
-        TraitRefFormat::OnlyTrait => {}
-    }
-
-    let trait_ = tr.hir_trait_id();
-    f.start_location_link(trait_.into());
-    write!(f, "{}", f.db.trait_data(trait_).name.display(f.db.upcast(), f.edition()))?;
-    f.end_location_link();
-    let substs = tr.substitution.as_slice(Interner);
-    hir_fmt_generics(f, &substs[1..], None, substs[0].ty(Interner))
-}
-
-pub struct TraitRefDisplayWrapper {
-    pub trait_ref: TraitRef,
-    pub format: TraitRefFormat,
-}
-
-impl HirDisplay for TraitRefDisplayWrapper {
+impl HirDisplay for TraitRef {
     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
-        fmt_trait_ref(f, &self.trait_ref, self.format)
+        let trait_ = self.hir_trait_id();
+        f.start_location_link(trait_.into());
+        write!(f, "{}", f.db.trait_data(trait_).name.display(f.db.upcast(), f.edition()))?;
+        f.end_location_link();
+        let substs = self.substitution.as_slice(Interner);
+        hir_fmt_generics(f, &substs[1..], None, substs[0].ty(Interner))
     }
 }
 
@@ -1830,11 +1796,16 @@ impl HirDisplay for WhereClause {
 
         match self {
             WhereClause::Implemented(trait_ref) => {
-                fmt_trait_ref(f, trait_ref, TraitRefFormat::SelfImplementsTrait)?;
+                trait_ref.self_type_parameter(Interner).hir_fmt(f)?;
+                write!(f, ": ")?;
+                trait_ref.hir_fmt(f)?;
             }
             WhereClause::AliasEq(AliasEq { alias: AliasTy::Projection(projection_ty), ty }) => {
                 write!(f, "<")?;
-                fmt_trait_ref(f, &projection_ty.trait_ref(f.db), TraitRefFormat::SelfAsTrait)?;
+                let trait_ref = &projection_ty.trait_ref(f.db);
+                trait_ref.self_type_parameter(Interner).hir_fmt(f)?;
+                write!(f, " as ")?;
+                trait_ref.hir_fmt(f)?;
                 write!(f, ">::",)?;
                 let type_alias = from_assoc_type_id(projection_ty.associated_ty_id);
                 f.start_location_link(type_alias.into());

src/tools/rust-analyzer/crates/hir/src/display.rs

@@ -743,18 +743,9 @@ impl HirDisplay for Static {
     }
 }
 
-pub struct TraitRefDisplayWrapper {
-    pub trait_ref: TraitRef,
-    pub format: hir_ty::display::TraitRefFormat,
-}
-
-impl HirDisplay for TraitRefDisplayWrapper {
+impl HirDisplay for TraitRef {
     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
-        hir_ty::display::TraitRefDisplayWrapper {
-            format: self.format,
-            trait_ref: self.trait_ref.trait_ref.clone(),
-        }
-        .hir_fmt(f)
+        self.trait_ref.hir_fmt(f)
     }
 }
 

src/tools/rust-analyzer/crates/hir/src/lib.rs

@@ -96,7 +96,6 @@ use crate::db::{DefDatabase, HirDatabase};
 pub use crate::{
     attrs::{resolve_doc_path_on, HasAttrs},
     diagnostics::*,
-    display::TraitRefDisplayWrapper,
     has_source::HasSource,
     semantics::{
         PathResolution, Semantics, SemanticsImpl, SemanticsScope, TypeInfo, VisibleTraits,
@@ -149,7 +148,7 @@ pub use {
     hir_ty::{
         consteval::ConstEvalError,
         diagnostics::UnsafetyReason,
-        display::{ClosureStyle, HirDisplay, HirDisplayError, HirWrite, TraitRefFormat},
+        display::{ClosureStyle, HirDisplay, HirDisplayError, HirWrite},
         dyn_compatibility::{DynCompatibilityViolation, MethodViolationCode},
         layout::LayoutError,
         mir::{MirEvalError, MirLowerError},

src/tools/rust-analyzer/crates/ide/src/moniker.rs

@@ -3,10 +3,7 @@
 
 use core::fmt;
 
-use hir::{
-    Adt, AsAssocItem, Crate, HirDisplay, MacroKind, Semantics, TraitRefDisplayWrapper,
-    TraitRefFormat,
-};
+use hir::{Adt, AsAssocItem, Crate, HirDisplay, MacroKind, Semantics};
 use ide_db::{
     base_db::{CrateOrigin, LangCrateOrigin},
     defs::{Definition, IdentClass},
@@ -312,15 +309,13 @@ fn def_to_non_local_moniker(
         match def {
             Definition::SelfType(impl_) => {
                 if let Some(trait_ref) = impl_.trait_ref(db) {
-                    // Trait impls use `trait_type` constraint syntax for the 2nd parameter.
-                    let trait_ref_for_display =
-                        TraitRefDisplayWrapper { trait_ref, format: TraitRefFormat::OnlyTrait };
+                    // Trait impls use the trait type for the 2nd parameter.
                     reverse_description.push(MonikerDescriptor {
-                        name: display(db, edition, module, trait_ref_for_display),
+                        name: display(db, edition, module, trait_ref),
                         desc: MonikerDescriptorKind::TypeParameter,
                     });
                 }
-                // Both inherent and trait impls use `self_type` as the first parameter.
+                // Both inherent and trait impls use the self type for the first parameter.
                 reverse_description.push(MonikerDescriptor {
                     name: display(db, edition, module, impl_.self_ty(db)),
                     desc: MonikerDescriptorKind::TypeParameter,