Edit error messages for rustc_resolve::AmbiguityKind variants

Emit description of the ambiguity as a note.

Co-authored-by: Noah Lev <camelidcamel@gmail.com>
Co-authored-by: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>

Author: 3 people

compiler/rustc_resolve/src/diagnostics.rs

@@ -1165,14 +1165,9 @@ impl<'a> Resolver<'a> {
             (b1, b2, misc1, misc2, false)
         };
 
-        let mut err = struct_span_err!(
-            self.session,
-            ident.span,
-            E0659,
-            "`{ident}` is ambiguous ({why})",
-            why = kind.descr()
-        );
+        let mut err = struct_span_err!(self.session, ident.span, E0659, "`{ident}` is ambiguous");
         err.span_label(ident.span, "ambiguous name");
+        err.note(&format!("ambiguous because of {}", kind.descr()));
 
         let mut could_refer_to = |b: &NameBinding<'_>, misc: AmbiguityErrorMisc, also: &str| {
             let what = self.binding_description(b, ident, misc == AmbiguityErrorMisc::FromPrelude);

compiler/rustc_resolve/src/lib.rs

@@ -728,23 +728,21 @@ enum AmbiguityKind {
 impl AmbiguityKind {
     fn descr(self) -> &'static str {
         match self {
-            AmbiguityKind::Import => "name vs any other name during import resolution",
-            AmbiguityKind::BuiltinAttr => "built-in attribute vs any other name",
-            AmbiguityKind::DeriveHelper => "derive helper attribute vs any other name",
+            AmbiguityKind::Import => "multiple potential import sources",
+            AmbiguityKind::BuiltinAttr => "a name conflict with a builtin attribute",
+            AmbiguityKind::DeriveHelper => "a name conflict with a derive helper attribute",
             AmbiguityKind::MacroRulesVsModularized => {
-                "`macro_rules` vs non-`macro_rules` from other module"
+                "a conflict between a `macro_rules` name and a non-`macro_rules` name from another module"
             }
             AmbiguityKind::GlobVsOuter => {
-                "glob import vs any other name from outer scope during import/macro resolution"
+                "a conflict between a name from a glob import and an outer scope during import or macro resolution"
             }
-            AmbiguityKind::GlobVsGlob => "glob import vs glob import in the same module",
+            AmbiguityKind::GlobVsGlob => "multiple glob imports of a name in the same module",
             AmbiguityKind::GlobVsExpanded => {
-                "glob import vs macro-expanded name in the same \
-                 module during import/macro resolution"
+                "a conflict between a name from a glob import and a macro-expanded name in the same module during import or macro resolution"
             }
             AmbiguityKind::MoreExpandedVsOuter => {
-                "macro-expanded name vs less macro-expanded name \
-                 from outer scope during import/macro resolution"
+                "a conflict between a macro-expanded name and a less macro-expanded name from outer scope during import or macro resolution"
             }
         }
     }

src/test/ui/binding/ambiguity-item.stderr

@@ -1,9 +1,10 @@
-error[E0659]: `f` is ambiguous (glob import vs glob import in the same module)
+error[E0659]: `f` is ambiguous
   --> $DIR/ambiguity-item.rs:14:13
    |
 LL |     let v = f;
    |             ^ ambiguous name
    |
+   = note: ambiguous because of multiple glob imports of a name in the same module
 note: `f` could refer to the function imported here
   --> $DIR/ambiguity-item.rs:6:5
    |
@@ -17,12 +18,13 @@ LL | use n::*; // OK, no conflict with `use m::*;`
    |     ^^^^
    = help: consider adding an explicit import of `f` to disambiguate
 
-error[E0659]: `f` is ambiguous (glob import vs glob import in the same module)
+error[E0659]: `f` is ambiguous
   --> $DIR/ambiguity-item.rs:16:9
    |
 LL |         f => {}
    |         ^ ambiguous name
    |
+   = note: ambiguous because of multiple glob imports of a name in the same module
 note: `f` could refer to the function imported here
   --> $DIR/ambiguity-item.rs:6:5
    |

src/test/ui/entry-point/imported_main_conflict.rs

@@ -1,5 +1,5 @@
 #![feature(imported_main)]
-//~^ ERROR `main` is ambiguous (glob import vs glob import in the same module)
+//~^ ERROR `main` is ambiguous
 mod m1 { pub(crate) fn main() {} }
 mod m2 { pub(crate) fn main() {} }
 

src/test/ui/entry-point/imported_main_conflict.stderr

@@ -1,5 +1,6 @@
-error[E0659]: `main` is ambiguous (glob import vs glob import in the same module)
+error[E0659]: `main` is ambiguous
    |
+   = note: ambiguous because of multiple glob imports of a name in the same module
 note: `main` could refer to the function imported here
   --> $DIR/imported_main_conflict.rs:6:5
    |

src/test/ui/error-codes/E0659.stderr

@@ -1,9 +1,10 @@
-error[E0659]: `foo` is ambiguous (glob import vs glob import in the same module)
+error[E0659]: `foo` is ambiguous
   --> $DIR/E0659.rs:15:15
    |
 LL |     collider::foo();
    |               ^^^ ambiguous name
    |
+   = note: ambiguous because of multiple glob imports of a name in the same module
 note: `foo` could refer to the function imported here
   --> $DIR/E0659.rs:10:13
    |

src/test/ui/imports/duplicate.stderr

@@ -8,12 +8,13 @@ LL |     use a::foo;
    |
    = note: `foo` must be defined only once in the value namespace of this module
 
-error[E0659]: `foo` is ambiguous (glob import vs glob import in the same module)
+error[E0659]: `foo` is ambiguous
   --> $DIR/duplicate.rs:46:15
    |
 LL |     use self::foo::bar;
    |               ^^^ ambiguous name
    |
+   = note: ambiguous because of multiple glob imports of a name in the same module
 note: `foo` could refer to the module imported here
   --> $DIR/duplicate.rs:43:9
    |
@@ -27,12 +28,13 @@ LL |     use self::m2::*;
    |         ^^^^^^^^^^^
    = help: consider adding an explicit import of `foo` to disambiguate
 
-error[E0659]: `foo` is ambiguous (glob import vs glob import in the same module)
+error[E0659]: `foo` is ambiguous
   --> $DIR/duplicate.rs:35:8
    |
 LL |     f::foo();
    |        ^^^ ambiguous name
    |
+   = note: ambiguous because of multiple glob imports of a name in the same module
 note: `foo` could refer to the function imported here
   --> $DIR/duplicate.rs:24:13
    |
@@ -46,12 +48,13 @@ LL |     pub use b::*;
    |             ^^^^
    = help: consider adding an explicit import of `foo` to disambiguate
 
-error[E0659]: `foo` is ambiguous (glob import vs glob import in the same module)
+error[E0659]: `foo` is ambiguous
   --> $DIR/duplicate.rs:49:9
    |
 LL |         foo::bar();
    |         ^^^ ambiguous name
    |
+   = note: ambiguous because of multiple glob imports of a name in the same module
 note: `foo` could refer to the module imported here
   --> $DIR/duplicate.rs:43:9
    |

src/test/ui/imports/extern-prelude-extern-crate-restricted-shadowing.stderr

@@ -9,12 +9,13 @@ LL | define_other_core!();
    |
    = note: this error originates in the macro `define_other_core` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error[E0659]: `Vec` is ambiguous (macro-expanded name vs less macro-expanded name from outer scope during import/macro resolution)
+error[E0659]: `Vec` is ambiguous
   --> $DIR/extern-prelude-extern-crate-restricted-shadowing.rs:13:9
    |
 LL |         Vec::panic!();
    |         ^^^ ambiguous name
    |
+   = note: ambiguous because of a conflict between a macro-expanded name and a less macro-expanded name from outer scope during import or macro resolution
 note: `Vec` could refer to the crate imported here
   --> $DIR/extern-prelude-extern-crate-restricted-shadowing.rs:5:9
    |

src/test/ui/imports/glob-shadowing.stderr

@@ -1,9 +1,10 @@
-error[E0659]: `env` is ambiguous (glob import vs any other name from outer scope during import/macro resolution)
+error[E0659]: `env` is ambiguous
   --> $DIR/glob-shadowing.rs:11:17
    |
 LL |         let x = env!("PATH");
    |                 ^^^ ambiguous name
    |
+   = note: ambiguous because of a conflict between a name from a glob import and an outer scope during import or macro resolution
    = note: `env` could refer to a macro from prelude
 note: `env` could also refer to the macro imported here
   --> $DIR/glob-shadowing.rs:9:9
@@ -13,12 +14,13 @@ LL |     use m::*;
    = help: consider adding an explicit import of `env` to disambiguate
    = help: or use `self::env` to refer to this macro unambiguously
 
-error[E0659]: `env` is ambiguous (glob import vs any other name from outer scope during import/macro resolution)
+error[E0659]: `env` is ambiguous
   --> $DIR/glob-shadowing.rs:19:21
    |
 LL |             let x = env!("PATH");
    |                     ^^^ ambiguous name
    |
+   = note: ambiguous because of a conflict between a name from a glob import and an outer scope during import or macro resolution
    = note: `env` could refer to a macro from prelude
 note: `env` could also refer to the macro imported here
   --> $DIR/glob-shadowing.rs:17:13
@@ -27,12 +29,13 @@ LL |         use m::*;
    |             ^^^^
    = help: consider adding an explicit import of `env` to disambiguate
 
-error[E0659]: `fenv` is ambiguous (glob import vs any other name from outer scope during import/macro resolution)
+error[E0659]: `fenv` is ambiguous
   --> $DIR/glob-shadowing.rs:29:21
    |
 LL |             let x = fenv!();
    |                     ^^^^ ambiguous name
    |
+   = note: ambiguous because of a conflict between a name from a glob import and an outer scope during import or macro resolution
 note: `fenv` could refer to the macro imported here
   --> $DIR/glob-shadowing.rs:27:13
    |

src/test/ui/imports/issue-53269.stderr

@@ -4,12 +4,13 @@ error[E0432]: unresolved import `nonexistent_module`
 LL |     use nonexistent_module::mac;
    |         ^^^^^^^^^^^^^^^^^^ maybe a missing crate `nonexistent_module`?
 
-error[E0659]: `mac` is ambiguous (`macro_rules` vs non-`macro_rules` from other module)
+error[E0659]: `mac` is ambiguous
   --> $DIR/issue-53269.rs:8:5
    |
 LL |     mac!();
    |     ^^^ ambiguous name
    |
+   = note: ambiguous because of a conflict between a `macro_rules` name and a non-`macro_rules` name from another module
 note: `mac` could refer to the macro defined here
   --> $DIR/issue-53269.rs:3:1
    |