Fixing bad suggestion for `_` in `const` type when a function #81885

[rust.git] / compiler / rustc_typeck / src / collect.rs

diff --git a/compiler/rustc_typeck/src/collect.rs b/compiler/rustc_typeck/src/collect.rs
index d589989511db17e1fb1ad59b02dfb65d2d0d6422..3d0220bfd67e7a244944e8a26ccd3139098e7511 100644 (file)
--- a/compiler/rustc_typeck/src/collect.rs
+++ b/compiler/rustc_typeck/src/collect.rs
@@ -50,8 +50,6 @@
 use rustc_target::spec::abi;
 use rustc_trait_selection::traits::error_reporting::suggestions::NextTypeParamName;
 
-use std::ops::ControlFlow;
-
 mod item_bounds;
 mod type_of;
 
@@ -143,6 +141,7 @@ struct CollectItemTypesVisitor<'tcx> {
     generics: &[hir::GenericParam<'_>],
     placeholder_types: Vec<Span>,
     suggest: bool,
+    is_fn: bool,
 ) {
     if placeholder_types.is_empty() {
         return;
@@ -173,7 +172,9 @@ struct CollectItemTypesVisitor<'tcx> {
     }
 
     let mut err = bad_placeholder_type(tcx, placeholder_types);
-    if suggest {
+    
+    // Suggest, but only if it is not a function
+    if suggest && !is_fn {
         err.multipart_suggestion(
             "use type parameters instead",
             sugg,
@@ -200,7 +201,14 @@ fn reject_placeholder_type_signatures_in_item(tcx: TyCtxt<'tcx>, item: &'tcx hir
     let mut visitor = PlaceholderHirTyCollector::default();
     visitor.visit_item(item);
 
-    placeholder_type_error(tcx, Some(generics.span), &generics.params[..], visitor.0, suggest);
+    placeholder_type_error(
+        tcx, 
+        Some(generics.span), 
+        &generics.params[..], 
+        visitor.0, 
+        suggest, 
+        false
+    );
 }
 
 impl Visitor<'tcx> for CollectItemTypesVisitor<'tcx> {
@@ -745,7 +753,7 @@ fn convert_trait_item(tcx: TyCtxt<'_>, trait_item_id: hir::HirId) {
             // Account for `const C: _;`.
             let mut visitor = PlaceholderHirTyCollector::default();
             visitor.visit_trait_item(trait_item);
-            placeholder_type_error(tcx, None, &[], visitor.0, false);
+            placeholder_type_error(tcx, None, &[], visitor.0, false, false);
         }
 
         hir::TraitItemKind::Type(_, Some(_)) => {
@@ -754,7 +762,7 @@ fn convert_trait_item(tcx: TyCtxt<'_>, trait_item_id: hir::HirId) {
             // Account for `type T = _;`.
             let mut visitor = PlaceholderHirTyCollector::default();
             visitor.visit_trait_item(trait_item);
-            placeholder_type_error(tcx, None, &[], visitor.0, false);
+            placeholder_type_error(tcx, None, &[], visitor.0, false, false);
         }
 
         hir::TraitItemKind::Type(_, None) => {
@@ -763,7 +771,7 @@ fn convert_trait_item(tcx: TyCtxt<'_>, trait_item_id: hir::HirId) {
             // even if there is no concrete type.
             let mut visitor = PlaceholderHirTyCollector::default();
             visitor.visit_trait_item(trait_item);
-            placeholder_type_error(tcx, None, &[], visitor.0, false);
+            placeholder_type_error(tcx, None, &[], visitor.0, false, false);
         }
     };
 
@@ -784,7 +792,7 @@ fn convert_impl_item(tcx: TyCtxt<'_>, impl_item_id: hir::HirId) {
             // Account for `type T = _;`
             let mut visitor = PlaceholderHirTyCollector::default();
             visitor.visit_impl_item(impl_item);
-            placeholder_type_error(tcx, None, &[], visitor.0, false);
+            placeholder_type_error(tcx, None, &[], visitor.0, false, false);
         }
         hir::ImplItemKind::Const(..) => {}
     }
@@ -2080,38 +2088,6 @@ fn visit_anon_const(&mut self, c: &'tcx hir::AnonConst) {
                 ));
             }
         }
-
-        // Look into `TyAlias`.
-        fn visit_ty(&mut self, ty: &'tcx hir::Ty<'tcx>) {
-            use ty::fold::{TypeFoldable, TypeVisitor};
-            struct TyAliasVisitor<'a, 'tcx> {
-                tcx: TyCtxt<'tcx>,
-                preds: &'a mut FxIndexSet<(ty::Predicate<'tcx>, Span)>,
-                span: Span,
-            }
-
-            impl<'a, 'tcx> TypeVisitor<'tcx> for TyAliasVisitor<'a, 'tcx> {
-                fn visit_const(&mut self, ct: &'tcx Const<'tcx>) -> ControlFlow<Self::BreakTy> {
-                    if let ty::ConstKind::Unevaluated(def, substs, None) = ct.val {
-                        self.preds.insert((
-                            ty::PredicateKind::ConstEvaluatable(def, substs).to_predicate(self.tcx),
-                            self.span,
-                        ));
-                    }
-                    ControlFlow::CONTINUE
-                }
-            }
-
-            if let hir::TyKind::Path(hir::QPath::Resolved(None, path)) = ty.kind {
-                if let Res::Def(DefKind::TyAlias, def_id) = path.res {
-                    let mut visitor =
-                        TyAliasVisitor { tcx: self.tcx, preds: &mut self.preds, span: path.span };
-                    self.tcx.type_of(def_id).visit_with(&mut visitor);
-                }
-            }
-
-            intravisit::walk_ty(self, ty)
-        }
     }
 
     let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);