resolve: Downgrade ambiguous_glob_imports to warn-by-default

But still keep it report-in-deps.

To revert after ~February 27 2026, when Rust 1.95 branches out from the main branch.

Author: petrochenkov

compiler/rustc_lint_defs/src/builtin.rs

@@ -4465,7 +4465,7 @@ declare_lint! {
     ///
     /// [future-incompatible]: ../index.md#future-incompatible-lints
     pub AMBIGUOUS_GLOB_IMPORTS,
-    Deny,
+    Warn,
     "detects certain glob imports that require reporting an ambiguity error",
     @future_incompatible = FutureIncompatibleInfo {
         reason: fcw!(FutureReleaseError #114095),

tests/ui/imports/ambiguous-10.rs

@@ -1,5 +1,5 @@
 // https://github.com/rust-lang/rust/pull/113099#issuecomment-1637022296
-
+//@ check-pass
 mod a {
     pub enum Token {}
 }
@@ -13,6 +13,6 @@ mod b {
 use crate::a::*;
 use crate::b::*;
 fn c(_: Token) {}
-//~^ ERROR `Token` is ambiguous
+//~^ WARN `Token` is ambiguous
 //~| WARNING this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
 fn main() { }

tests/ui/imports/ambiguous-10.stderr

@@ -1,4 +1,4 @@
-error: `Token` is ambiguous
+warning: `Token` is ambiguous
   --> $DIR/ambiguous-10.rs:15:9
    |
 LL | fn c(_: Token) {}
@@ -19,12 +19,12 @@ note: `Token` could also refer to the enum imported here
 LL | use crate::b::*;
    |     ^^^^^^^^^^^
    = help: consider adding an explicit import of `Token` to disambiguate
-   = note: `#[deny(ambiguous_glob_imports)]` (part of `#[deny(future_incompatible)]`) on by default
+   = note: `#[warn(ambiguous_glob_imports)]` (part of `#[warn(future_incompatible)]`) on by default
 
-error: aborting due to 1 previous error
+warning: 1 warning emitted
 
 Future incompatibility report: Future breakage diagnostic:
-error: `Token` is ambiguous
+warning: `Token` is ambiguous
   --> $DIR/ambiguous-10.rs:15:9
    |
 LL | fn c(_: Token) {}
@@ -45,5 +45,5 @@ note: `Token` could also refer to the enum imported here
 LL | use crate::b::*;
    |     ^^^^^^^^^^^
    = help: consider adding an explicit import of `Token` to disambiguate
-   = note: `#[deny(ambiguous_glob_imports)]` (part of `#[deny(future_incompatible)]`) on by default
+   = note: `#[warn(ambiguous_glob_imports)]` (part of `#[warn(future_incompatible)]`) on by default
 

tests/ui/imports/ambiguous-12.rs

@@ -1,5 +1,5 @@
 // https://github.com/rust-lang/rust/pull/113099#issuecomment-1637022296
-
+//@ check-pass
 macro_rules! m {
     () => {
         pub fn b() {}
@@ -19,6 +19,6 @@ use crate::public::*;
 
 fn main() {
     b();
-    //~^ ERROR `b` is ambiguous
+    //~^ WARN `b` is ambiguous
     //~| WARNING this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
 }

tests/ui/imports/ambiguous-12.stderr

@@ -1,4 +1,4 @@
-error: `b` is ambiguous
+warning: `b` is ambiguous
   --> $DIR/ambiguous-12.rs:21:5
    |
 LL |     b();
@@ -19,12 +19,12 @@ note: `b` could also refer to the function imported here
 LL | use crate::public::*;
    |     ^^^^^^^^^^^^^^^^
    = help: consider adding an explicit import of `b` to disambiguate
-   = note: `#[deny(ambiguous_glob_imports)]` (part of `#[deny(future_incompatible)]`) on by default
+   = note: `#[warn(ambiguous_glob_imports)]` (part of `#[warn(future_incompatible)]`) on by default
 
-error: aborting due to 1 previous error
+warning: 1 warning emitted
 
 Future incompatibility report: Future breakage diagnostic:
-error: `b` is ambiguous
+warning: `b` is ambiguous
   --> $DIR/ambiguous-12.rs:21:5
    |
 LL |     b();
@@ -45,5 +45,5 @@ note: `b` could also refer to the function imported here
 LL | use crate::public::*;
    |     ^^^^^^^^^^^^^^^^
    = help: consider adding an explicit import of `b` to disambiguate
-   = note: `#[deny(ambiguous_glob_imports)]` (part of `#[deny(future_incompatible)]`) on by default
+   = note: `#[warn(ambiguous_glob_imports)]` (part of `#[warn(future_incompatible)]`) on by default
 

tests/ui/imports/ambiguous-13.rs

@@ -1,5 +1,5 @@
 // https://github.com/rust-lang/rust/pull/113099#issuecomment-1637022296
-
+//@ check-pass
 pub mod object {
     #[derive(Debug)]
     pub struct Rect;
@@ -16,6 +16,6 @@ use crate::object::*;
 use crate::content::*;
 
 fn a(_: Rect) {}
-//~^ ERROR `Rect` is ambiguous
+//~^ WARN `Rect` is ambiguous
 //~| WARNING this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
 fn main() { }

tests/ui/imports/ambiguous-13.stderr

@@ -1,4 +1,4 @@
-error: `Rect` is ambiguous
+warning: `Rect` is ambiguous
   --> $DIR/ambiguous-13.rs:18:9
    |
 LL | fn a(_: Rect) {}
@@ -19,12 +19,12 @@ note: `Rect` could also refer to the struct imported here
 LL | use crate::content::*;
    |     ^^^^^^^^^^^^^^^^^
    = help: consider adding an explicit import of `Rect` to disambiguate
-   = note: `#[deny(ambiguous_glob_imports)]` (part of `#[deny(future_incompatible)]`) on by default
+   = note: `#[warn(ambiguous_glob_imports)]` (part of `#[warn(future_incompatible)]`) on by default
 
-error: aborting due to 1 previous error
+warning: 1 warning emitted
 
 Future incompatibility report: Future breakage diagnostic:
-error: `Rect` is ambiguous
+warning: `Rect` is ambiguous
   --> $DIR/ambiguous-13.rs:18:9
    |
 LL | fn a(_: Rect) {}
@@ -45,5 +45,5 @@ note: `Rect` could also refer to the struct imported here
 LL | use crate::content::*;
    |     ^^^^^^^^^^^^^^^^^
    = help: consider adding an explicit import of `Rect` to disambiguate
-   = note: `#[deny(ambiguous_glob_imports)]` (part of `#[deny(future_incompatible)]`) on by default
+   = note: `#[warn(ambiguous_glob_imports)]` (part of `#[warn(future_incompatible)]`) on by default
 

tests/ui/imports/ambiguous-14.rs

@@ -1,6 +1,6 @@
 //@ edition:2015
 // https://github.com/rust-lang/rust/issues/98467
-
+//@ check-pass
 mod a {
     pub fn foo() {}
 }
@@ -21,6 +21,6 @@ mod g {
 
 fn main() {
     g::foo();
-    //~^ ERROR `foo` is ambiguous
+    //~^ WARN `foo` is ambiguous
     //~| WARNING this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
 }

tests/ui/imports/ambiguous-14.stderr

@@ -1,4 +1,4 @@
-error: `foo` is ambiguous
+warning: `foo` is ambiguous
   --> $DIR/ambiguous-14.rs:23:8
    |
 LL |     g::foo();
@@ -19,12 +19,12 @@ note: `foo` could also refer to the function imported here
 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
+   = note: `#[warn(ambiguous_glob_imports)]` (part of `#[warn(future_incompatible)]`) on by default
 
-error: aborting due to 1 previous error
+warning: 1 warning emitted
 
 Future incompatibility report: Future breakage diagnostic:
-error: `foo` is ambiguous
+warning: `foo` is ambiguous
   --> $DIR/ambiguous-14.rs:23:8
    |
 LL |     g::foo();
@@ -45,5 +45,5 @@ note: `foo` could also refer to the function imported here
 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
+   = note: `#[warn(ambiguous_glob_imports)]` (part of `#[warn(future_incompatible)]`) on by default
 

tests/ui/imports/ambiguous-15.rs

@@ -1,5 +1,5 @@
 // https://github.com/rust-lang/rust/pull/113099#issuecomment-1638206152
-
+//@ check-pass
 mod t2 {
     #[derive(Debug)]
     pub enum Error {}
@@ -20,7 +20,7 @@ mod t3 {
 
 use self::t3::*;
 fn a<E: Error>(_: E) {}
-//~^ ERROR `Error` is ambiguous
+//~^ WARN `Error` is ambiguous
 //~| WARNING this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
 
 fn main() {}