Adding suggestion for E0530

compiler/rustc_resolve/src/diagnostics.rs

@@ -28,7 +28,7 @@ use rustc_span::{BytePos, Span};
 use tracing::debug;
 
 use crate::imports::{Import, ImportKind, ImportResolver};
-use crate::late::Rib;
+use crate::late::{PatternSource, Rib};
 use crate::path_names_to_string;
 use crate::{AmbiguityError, AmbiguityErrorMisc, AmbiguityKind, BindingError, Finalize};
 use crate::{HasGenericParams, MacroRulesScope, Module, ModuleKind, ModuleOrUniformRoot};
@@ -896,25 +896,40 @@ impl<'a> Resolver<'a> {
                 err
             }
             ResolutionError::BindingShadowsSomethingUnacceptable {
-                shadowing_binding_descr,
+                shadowing_binding,
                 name,
                 participle,
                 article,
-                shadowed_binding_descr,
+                shadowed_binding,
                 shadowed_binding_span,
             } => {
+                let shadowed_binding_descr = shadowed_binding.descr();
                 let mut err = struct_span_err!(
                     self.session,
                     span,
                     E0530,
                     "{}s cannot shadow {}s",
-                    shadowing_binding_descr,
+                    shadowing_binding.descr(),
                     shadowed_binding_descr,
                 );
                 err.span_label(
                     span,
                     format!("cannot be named the same as {} {}", article, shadowed_binding_descr),
                 );
+                match (shadowing_binding, shadowed_binding) {
+                    (
+                        PatternSource::Match,
+                        Res::Def(DefKind::Ctor(CtorOf::Variant | CtorOf::Struct, CtorKind::Fn), _),
+                    ) => {
+                        err.span_suggestion(
+                            span,
+                            "try specify the pattern arguments",
+                            format!("{}(..)", name),
+                            Applicability::Unspecified,
+                        );
+                    }
+                    _ => (),
+                }
                 let msg =
                     format!("the {} `{}` is {} here", shadowed_binding_descr, name, participle);
                 err.span_label(shadowed_binding_span, msg);

compiler/rustc_resolve/src/late.rs

@@ -50,7 +50,7 @@ struct BindingInfo {
 }
 
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
-enum PatternSource {
+pub enum PatternSource {
     Match,
     Let,
     For,
@@ -64,7 +64,7 @@ enum IsRepeatExpr {
 }
 
 impl PatternSource {
-    fn descr(self) -> &'static str {
+    pub fn descr(self) -> &'static str {
         match self {
             PatternSource::Match => "match binding",
             PatternSource::Let => "let binding",
@@ -2845,11 +2845,11 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                 self.report_error(
                     ident.span,
                     ResolutionError::BindingShadowsSomethingUnacceptable {
-                        shadowing_binding_descr: pat_src.descr(),
+                        shadowing_binding: pat_src,
                         name: ident.name,
                         participle: if binding.is_import() { "imported" } else { "defined" },
                         article: binding.res().article(),
-                        shadowed_binding_descr: binding.res().descr(),
+                        shadowed_binding: binding.res(),
                         shadowed_binding_span: binding.span,
                     },
                 );
@@ -2861,11 +2861,11 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                 self.report_error(
                     ident.span,
                     ResolutionError::BindingShadowsSomethingUnacceptable {
-                        shadowing_binding_descr: pat_src.descr(),
+                        shadowing_binding: pat_src,
                         name: ident.name,
                         participle: "defined",
                         article: res.article(),
-                        shadowed_binding_descr: res.descr(),
+                        shadowed_binding: res,
                         shadowed_binding_span: self.r.opt_span(def_id).expect("const parameter defined outside of local crate"),
                     }
                 );

compiler/rustc_resolve/src/lib.rs

@@ -61,7 +61,7 @@ use tracing::debug;
 
 use diagnostics::{ImportSuggestion, LabelSuggestion, Suggestion};
 use imports::{Import, ImportKind, ImportResolver, NameResolution};
-use late::{HasGenericParams, PathSource};
+use late::{HasGenericParams, PathSource, PatternSource};
 use macros::{MacroRulesBinding, MacroRulesScope, MacroRulesScopeRef};
 
 use crate::access_levels::AccessLevelsVisitor;
@@ -230,11 +230,11 @@ enum ResolutionError<'a> {
     ),
     /// Error E0530: `X` bindings cannot shadow `Y`s.
     BindingShadowsSomethingUnacceptable {
-        shadowing_binding_descr: &'static str,
+        shadowing_binding: PatternSource,
         name: Symbol,
         participle: &'static str,
         article: &'static str,
-        shadowed_binding_descr: &'static str,
+        shadowed_binding: Res,
         shadowed_binding_span: Span,
     },
     /// Error E0128: generic parameters with a default cannot use forward-declared identifiers.

src/test/ui/empty/empty-struct-tuple-pat.stderr

@@ -5,7 +5,10 @@ LL | struct Empty2();
    | ---------------- the tuple struct `Empty2` is defined here
 ...
 LL |         Empty2 => ()
-   |         ^^^^^^ cannot be named the same as a tuple struct
+   |         ^^^^^^
+   |         |
+   |         cannot be named the same as a tuple struct
+   |         help: try specify the pattern arguments: `Empty2(..)`
 
 error[E0530]: match bindings cannot shadow tuple structs
   --> $DIR/empty-struct-tuple-pat.rs:25:9
@@ -14,7 +17,10 @@ LL | use empty_struct::*;
    |     --------------- the tuple struct `XEmpty6` is imported here
 ...
 LL |         XEmpty6 => ()
-   |         ^^^^^^^ cannot be named the same as a tuple struct
+   |         ^^^^^^^
+   |         |
+   |         cannot be named the same as a tuple struct
+   |         help: try specify the pattern arguments: `XEmpty6(..)`
 
 error[E0532]: expected unit struct, unit variant or constant, found tuple variant `E::Empty4`
   --> $DIR/empty-struct-tuple-pat.rs:29:9

src/test/ui/pattern/pat-tuple-field-count-cross.stderr

@@ -5,7 +5,10 @@ LL | use declarations_for_tuple_field_count_errors::*;
    |     -------------------------------------------- the tuple struct `Z1` is imported here
 ...
 LL |         Z1 => {}
-   |         ^^ cannot be named the same as a tuple struct
+   |         ^^
+   |         |
+   |         cannot be named the same as a tuple struct
+   |         help: try specify the pattern arguments: `Z1(..)`
 
 error[E0532]: expected tuple struct or tuple variant, found unit struct `Z0`
   --> $DIR/pat-tuple-field-count-cross.rs:9:9

src/test/ui/pattern/pat-tuple-overfield.stderr

@@ -5,7 +5,10 @@ LL | struct Z1();
    | ------------ the tuple struct `Z1` is defined here
 ...
 LL |         Z1 => {}
-   |         ^^ cannot be named the same as a tuple struct
+   |         ^^
+   |         |
+   |         cannot be named the same as a tuple struct
+   |         help: try specify the pattern arguments: `Z1(..)`
 
 error[E0532]: expected tuple struct or tuple variant, found unit struct `Z0`
   --> $DIR/pat-tuple-overfield.rs:52:9

src/test/ui/pattern/pattern-binding-disambiguation.stderr

@@ -5,7 +5,10 @@ LL | struct TupleStruct();
    | --------------------- the tuple struct `TupleStruct` is defined here
 ...
 LL |         TupleStruct => {}
-   |         ^^^^^^^^^^^ cannot be named the same as a tuple struct
+   |         ^^^^^^^^^^^
+   |         |
+   |         cannot be named the same as a tuple struct
+   |         help: try specify the pattern arguments: `TupleStruct(..)`
 
 error[E0530]: match bindings cannot shadow tuple variants
   --> $DIR/pattern-binding-disambiguation.rs:33:9
@@ -14,7 +17,10 @@ LL | use E::*;
    |     ---- the tuple variant `TupleVariant` is imported here
 ...
 LL |         TupleVariant => {}
-   |         ^^^^^^^^^^^^ cannot be named the same as a tuple variant
+   |         ^^^^^^^^^^^^
+   |         |
+   |         cannot be named the same as a tuple variant
+   |         help: try specify the pattern arguments: `TupleVariant(..)`
 
 error[E0530]: match bindings cannot shadow struct variants
   --> $DIR/pattern-binding-disambiguation.rs:36:9