resolve: Tweak overwriting with ambiguous globs

Do not overwrite unless necessary, and combine both globs instead of losing the first one.

Author: petrochenkov

compiler/rustc_resolve/src/imports.rs

@@ -384,10 +384,9 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             // We are glob-importing the same item but with greater visibility.
             old_glob_decl.vis.set_unchecked(glob_decl.vis());
             old_glob_decl
-        } else if glob_decl.is_ambiguity_recursive() {
-            // Overwriting with an ambiguous glob import.
-            glob_decl.warn_ambiguity.set_unchecked(true);
-            glob_decl
+        } else if glob_decl.is_ambiguity_recursive() && !old_glob_decl.is_ambiguity_recursive() {
+            // Overwriting a non-ambiguous glob import with an ambiguous glob import.
+            self.new_decl_with_ambiguity(old_glob_decl, glob_decl, true)
         } else {
             old_glob_decl
         }

tests/ui/imports/ambiguous-14.stderr

@@ -8,15 +8,15 @@ LL |     g::foo();
    = note: for more information, see issue #114095 <https://github.com/rust-lang/rust/issues/114095>
    = note: ambiguous because of multiple glob imports of a name in the same module
 note: `foo` could refer to the function imported here
-  --> $DIR/ambiguous-14.rs:13:13
+  --> $DIR/ambiguous-14.rs:18:13
    |
 LL |     pub use a::*;
    |             ^^^^
    = help: consider adding an explicit import of `foo` to disambiguate
 note: `foo` could also refer to the function imported here
-  --> $DIR/ambiguous-14.rs:14:13
+  --> $DIR/ambiguous-14.rs:19:13
    |
-LL |     pub use b::*;
+LL |     pub use f::*;
    |             ^^^^
    = help: consider adding an explicit import of `foo` to disambiguate
    = note: `#[deny(ambiguous_glob_imports)]` (part of `#[deny(future_incompatible)]`) on by default
@@ -34,15 +34,15 @@ LL |     g::foo();
    = note: for more information, see issue #114095 <https://github.com/rust-lang/rust/issues/114095>
    = note: ambiguous because of multiple glob imports of a name in the same module
 note: `foo` could refer to the function imported here
-  --> $DIR/ambiguous-14.rs:13:13
+  --> $DIR/ambiguous-14.rs:18:13
    |
 LL |     pub use a::*;
    |             ^^^^
    = help: consider adding an explicit import of `foo` to disambiguate
 note: `foo` could also refer to the function imported here
-  --> $DIR/ambiguous-14.rs:14:13
+  --> $DIR/ambiguous-14.rs:19:13
    |
-LL |     pub use b::*;
+LL |     pub use f::*;
    |             ^^^^
    = help: consider adding an explicit import of `foo` to disambiguate
    = note: `#[deny(ambiguous_glob_imports)]` (part of `#[deny(future_incompatible)]`) on by default

tests/ui/imports/duplicate.stderr

@@ -78,15 +78,15 @@ LL |     g::foo();
    = note: for more information, see issue #114095 <https://github.com/rust-lang/rust/issues/114095>
    = 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
+  --> $DIR/duplicate.rs:29:13
    |
 LL |     pub use crate::a::*;
    |             ^^^^^^^^^^^
    = help: consider adding an explicit import of `foo` to disambiguate
 note: `foo` could also refer to the function imported here
-  --> $DIR/duplicate.rs:25:13
+  --> $DIR/duplicate.rs:30:13
    |
-LL |     pub use crate::b::*;
+LL |     pub use crate::f::*;
    |             ^^^^^^^^^^^
    = help: consider adding an explicit import of `foo` to disambiguate
    = note: `#[deny(ambiguous_glob_imports)]` (part of `#[deny(future_incompatible)]`) on by default
@@ -106,15 +106,15 @@ LL |     g::foo();
    = note: for more information, see issue #114095 <https://github.com/rust-lang/rust/issues/114095>
    = 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
+  --> $DIR/duplicate.rs:29:13
    |
 LL |     pub use crate::a::*;
    |             ^^^^^^^^^^^
    = help: consider adding an explicit import of `foo` to disambiguate
 note: `foo` could also refer to the function imported here
-  --> $DIR/duplicate.rs:25:13
+  --> $DIR/duplicate.rs:30:13
    |
-LL |     pub use crate::b::*;
+LL |     pub use crate::f::*;
    |             ^^^^^^^^^^^
    = help: consider adding an explicit import of `foo` to disambiguate
    = note: `#[deny(ambiguous_glob_imports)]` (part of `#[deny(future_incompatible)]`) on by default