Only suggest signature fixes for non-local traits

Author: reddevilmidzy

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -1823,21 +1823,24 @@ fn compare_number_of_method_arguments<'tcx>(
                 })
             });
 
-        if let (Some(span), Some(missing)) = (impl_inputs_span, missing_params) {
-            let sep = if impl_number_args == 0 { "" } else { ", " };
-            err.span_suggestion_verbose(
-                span.shrink_to_hi(),
-                "add the missing parameter from the trait",
-                format!("{sep}{missing}"),
-                Applicability::MaybeIncorrect,
-            );
-        } else if let (Some(span), Some(suggestion)) = (impl_inputs_span, full_suggestion) {
-            err.span_suggestion_verbose(
-                span,
-                "modify the signature to match the trait definition",
-                suggestion,
-                Applicability::MaybeIncorrect,
-            );
+        // Only emit verbose suggestions when the trait span isn’t local (e.g., cross-crate).
+        if trait_span.is_none() {
+            if let (Some(span), Some(missing)) = (impl_inputs_span, missing_params) {
+                let sep = if impl_number_args == 0 { "" } else { ", " };
+                err.span_suggestion_verbose(
+                    span.shrink_to_hi(),
+                    "add the missing parameter from the trait",
+                    format!("{sep}{missing}"),
+                    Applicability::MaybeIncorrect,
+                );
+            } else if let (Some(span), Some(suggestion)) = (impl_inputs_span, full_suggestion) {
+                err.span_suggestion_verbose(
+                    span,
+                    "modify the signature to match the trait definition",
+                    suggestion,
+                    Applicability::MaybeIncorrect,
+                );
+            }
         }
 
         return Err(err.emit_unless_delay(delay));

tests/ui/error-codes/E0050.rs

@@ -8,11 +8,8 @@ struct Bar;
 
 impl Foo for Bar {
     fn foo(&self) -> bool { true } //~ ERROR E0050
-    //~| HELP: modify the signature to match the trait definition
     fn bar(&self) { } //~ ERROR E0050
-    //~| HELP: modify the signature to match the trait definition
     fn less(&self, x: u8, y: u8, z: u8) { } //~ ERROR E0050
-    //~| HELP: modify the signature to match the trait definition
 }
 
 fn main() {

tests/ui/error-codes/E0050.stderr

@@ -6,11 +6,6 @@ LL |     fn foo(&self, x: u8) -> bool;
 ...
 LL |     fn foo(&self) -> bool { true }
    |            ^^^^^ expected 2 parameters, found 1
-   |
-help: modify the signature to match the trait definition
-   |
-LL |     fn foo(&self, x: u8) -> bool { true }
-   |                 +++++++
 
 error[E0050]: method `bar` has 1 parameter but the declaration in trait `Foo::bar` has 4
   --> $DIR/E0050.rs:12:12
@@ -20,11 +15,6 @@ LL |     fn bar(&self, x: u8, y: u8, z: u8);
 ...
 LL |     fn bar(&self) { }
    |            ^^^^^ expected 4 parameters, found 1
-   |
-help: modify the signature to match the trait definition
-   |
-LL |     fn bar(&self, x: u8, y: u8, z: u8) { }
-   |                 +++++++++++++++++++++
 
 error[E0050]: method `less` has 4 parameters but the declaration in trait `Foo::less` has 1
   --> $DIR/E0050.rs:14:13
@@ -34,12 +24,6 @@ LL |     fn less(&self);
 ...
 LL |     fn less(&self, x: u8, y: u8, z: u8) { }
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ expected 1 parameter, found 4
-   |
-help: modify the signature to match the trait definition
-   |
-LL -     fn less(&self, x: u8, y: u8, z: u8) { }
-LL +     fn less(&self) { }
-   |
 
 error: aborting due to 3 previous errors
 

tests/ui/impl-trait/in-trait/method-signature-matches.too_few.stderr

@@ -6,11 +6,6 @@ LL |     fn come_on_a_little_more_effort(_: (), _: (), _: ()) -> impl Sized;
 ...
 LL |     fn come_on_a_little_more_effort() {}
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected 3 parameters, found 0
-   |
-help: add the missing parameter from the trait
-   |
-LL |     fn come_on_a_little_more_effort(_: (), _: (), _: ()) {}
-   |                                     +++++++++++++++++++
 
 error: aborting due to 1 previous error
 

tests/ui/impl-trait/in-trait/method-signature-matches.too_many.stderr

@@ -6,12 +6,6 @@ LL |     fn calm_down_please() -> impl Sized;
 ...
 LL |     fn calm_down_please(_: (), _: (), _: ()) {}
    |                            ^^^^^^^^^^^^^^^^ expected 0 parameters, found 3
-   |
-help: modify the signature to match the trait definition
-   |
-LL -     fn calm_down_please(_: (), _: (), _: ()) {}
-LL +     fn calm_down_please() {}
-   |
 
 error: aborting due to 1 previous error
 

tests/ui/suggestions/bad-infer-in-trait-impl.stderr

@@ -12,12 +12,6 @@ LL |     fn bar();
 ...
 LL |     fn bar(s: _) {}
    |               ^ expected 0 parameters, found 1
-   |
-help: modify the signature to match the trait definition
-   |
-LL -     fn bar(s: _) {}
-LL +     fn bar() {}
-   |
 
 error: aborting due to 2 previous errors
 

tests/ui/suggestions/trait-impl-mismatched-with-alias.stderr

@@ -6,11 +6,6 @@ LL |     fn foo(a: i32, b: u32);
 ...
 LL |     fn foo(a: AliasOfI32) {}
    |               ^^^^^^^^^^ expected 2 parameters, found 1
-   |
-help: add the missing parameter from the trait
-   |
-LL |     fn foo(a: AliasOfI32, b: u32) {}
-   |                         ++++++++
 
 error[E0050]: method `foo` has 1 parameter but the declaration in trait `Foo::foo` has 2
   --> $DIR/trait-impl-mismatched-with-alias.rs:15:15
@@ -20,12 +15,6 @@ LL |     fn foo(a: i32, b: u32);
 ...
 LL |     fn foo(a: AliasOfU32) {}
    |               ^^^^^^^^^^ expected 2 parameters, found 1
-   |
-help: modify the signature to match the trait definition
-   |
-LL -     fn foo(a: AliasOfU32) {}
-LL +     fn foo(a: i32, b: u32) {}
-   |
 
 error: aborting due to 2 previous errors
 

tests/ui/traits/impl-different-num-params.stderr

@@ -6,11 +6,6 @@ LL |     fn bar(&self, x: usize) -> Self;
 ...
 LL |     fn bar(&self) -> isize {
    |            ^^^^^ expected 2 parameters, found 1
-   |
-help: modify the signature to match the trait definition
-   |
-LL |     fn bar(&self, x: usize) -> isize {
-   |                 ++++++++++
 
 error: aborting due to 1 previous error
 

tests/ui/traits/trait-method-signature-mismatch.stderr

@@ -7,15 +7,6 @@ LL |       fn foo(&mut self, x: i32, y: i32) -> i32;
 LL | /         &mut self,
 LL | |         x: i32,
    | |______________^ expected 3 parameters, found 2
-   |
-help: modify the signature to match the trait definition
-   |
-LL -     fn foo(
-LL -         &mut self,
-LL -         x: i32,
-LL -     ) {
-LL +     fn foo(&mut self, x: i32, y: i32) {
-   |
 
 error: aborting due to 1 previous error