Rollup merge of #123744 - compiler-errors:redundant-due-to-glob, r=pe…

…trochenkov

Silence `unused_imports` for redundant imports

Quick fix for #121708 (comment)

r? `@petrochenkov` cc `@joshtriplett`

I think this is right, would like confirmation. I also think it's weird that we're using `=` to assign to `is_redundant` but using `per_ns` for the actual spans. Seems like this could be weirdly order dependent, but that's unrelated to this change.

compiler/rustc_resolve/src/imports.rs

@@ -1391,13 +1391,15 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
             let mut redundant_spans: Vec<_> = redundant_span.present_items().collect();
             redundant_spans.sort();
             redundant_spans.dedup();
+            /* FIXME(unused_imports): Add this back as a new lint
             self.lint_buffer.buffer_lint_with_diagnostic(
                 UNUSED_IMPORTS,
                 id,
                 import.span,
                 format!("the item `{source}` is imported redundantly"),
                 BuiltinLintDiag::RedundantImport(redundant_spans, source),
             );
+            */
             return true;
         }
 

compiler/rustc_resolve/src/lib.rs

@@ -177,7 +177,7 @@ enum ImplTraitContext {
 
 /// Used for tracking import use types which will be used for redundant import checking.
 /// ### Used::Scope Example
-///  ```rust,compile_fail
+///  ```rust,ignore (redundant_imports)
 /// #![deny(unused_imports)]
 /// use std::mem::drop;
 /// fn main() {

tests/ui/imports/redundant-import-extern-prelude.rs

@@ -1,17 +1,16 @@
+//@ check-pass
 // Check that we detect imports that are redundant due to the extern prelude
 // and that we emit a reasonable diagnostic.
 // issue: rust-lang/rust#121915
-//~^^^ NOTE the item `aux_issue_121915` is already defined by the extern prelude
 
 // See also the discussion in <https://github.com/rust-lang/rust/pull/122954>.
 
 //@ compile-flags: --extern aux_issue_121915 --edition 2018
 //@ aux-build: aux-issue-121915.rs
 
 #[deny(unused_imports)]
-//~^ NOTE the lint level is defined here
 fn main() {
     use aux_issue_121915;
-    //~^ ERROR the item `aux_issue_121915` is imported redundantly
+    //FIXME(unused_imports): ~^ ERROR the item `aux_issue_121915` is imported redundantly
     aux_issue_121915::item();
 }

tests/ui/imports/redundant-import-issue-121915-2015.rs

@@ -1,3 +1,4 @@
+//@ check-pass
 //@ compile-flags: --extern aux_issue_121915 --edition 2015
 //@ aux-build: aux-issue-121915.rs
 
@@ -6,6 +7,6 @@ extern crate aux_issue_121915;
 #[deny(unused_imports)]
 fn main() {
     use aux_issue_121915;
-    //~^ ERROR the item `aux_issue_121915` is imported redundantly
+    //FIXME(unused_imports): ~^ ERROR the item `aux_issue_121915` is imported redundantly
     aux_issue_121915::item();
 }

tests/ui/imports/redundant-import-lang-prelude-attr.rs

@@ -1,6 +1,6 @@
+//@ check-pass
 // Check that we detect imports (of built-in attributes) that are redundant due to
 // the language prelude and that we emit a reasonable diagnostic.
-//~^^ NOTE the item `allow` is already defined by the extern prelude
 
 // Note that we use the term "extern prelude" in the label even though "language prelude"
 // would be more correct. However, it's not worth special-casing this.
@@ -10,9 +10,8 @@
 //@ edition: 2018
 
 #![deny(unused_imports)]
-//~^ NOTE the lint level is defined here
 
-use allow; //~ ERROR the item `allow` is imported redundantly
+use allow; //FIXME(unused_imports): ~ ERROR the item `allow` is imported redundantly
 
 #[allow(unused)]
 fn main() {}

tests/ui/imports/redundant-import-lang-prelude.rs

@@ -1,17 +1,16 @@
+//@ check-pass
 // Check that we detect imports that are redundant due to the language prelude
 // and that we emit a reasonable diagnostic.
-//~^^ NOTE the item `u8` is already defined by the extern prelude
 
 // Note that we use the term "extern prelude" in the label even though "language prelude"
 // would be more correct. However, it's not worth special-casing this.
 
 // See also the discussion in <https://github.com/rust-lang/rust/pull/122954>.
 
 #![deny(unused_imports)]
-//~^ NOTE the lint level is defined here
 
 use std::primitive::u8;
-//~^ ERROR the item `u8` is imported redundantly
+//FIXME(unused_imports): ~^ ERROR the item `u8` is imported redundantly
 
 const _: u8 = 0;
 

tests/ui/imports/suggest-remove-issue-121315.rs

@@ -1,19 +1,20 @@
 //@ compile-flags: --edition 2021
+
 #![deny(unused_imports)]
 #![allow(dead_code)]
 
 fn test0() {
     // Test remove FlatUnused
     use std::convert::TryFrom;
-    //~^ ERROR the item `TryFrom` is imported redundantly
+    //FIXME(unused_imports): ~^ ERROR the item `TryFrom` is imported redundantly
     let _ = u32::try_from(5i32);
 }
 
 fn test1() {
     // FIXME(yukang) Test remove NestedFullUnused
     use std::convert::{TryFrom, TryInto};
-    //~^ ERROR the item `TryFrom` is imported redundantly
-    //~| ERROR the item `TryInto` is imported redundantly
+    //FIXME(unused_imports): ~^ ERROR the item `TryFrom` is imported redundantly
+    //FIXME(unused_imports): ~| ERROR the item `TryInto` is imported redundantly
 
     let _ = u32::try_from(5i32);
     let _a: i32 = u32::try_into(5u32).unwrap();
@@ -23,7 +24,7 @@ fn test2() {
     // FIXME(yukang): Test remove both redundant and unused
     use std::convert::{AsMut, Into};
     //~^ ERROR unused import: `AsMut`
-    //~| ERROR the item `Into` is imported redundantly
+    //FIXME(unused_imports): ~| ERROR the item `Into` is imported redundantly
 
     let _a: u32 = (5u8).into();
 }

tests/ui/imports/suggest-remove-issue-121315.stderr

@@ -1,56 +1,20 @@
-error: the item `TryFrom` is imported redundantly
-  --> $DIR/suggest-remove-issue-121315.rs:7:9
-   |
-LL |     use std::convert::TryFrom;
-   |         ^^^^^^^^^^^^^^^^^^^^^
-  --> $SRC_DIR/std/src/prelude/mod.rs:LL:COL
-   |
-   = note: the item `TryFrom` is already defined here
-   |
-note: the lint level is defined here
-  --> $DIR/suggest-remove-issue-121315.rs:2:9
-   |
-LL | #![deny(unused_imports)]
-   |         ^^^^^^^^^^^^^^
-
-error: the item `TryFrom` is imported redundantly
-  --> $DIR/suggest-remove-issue-121315.rs:14:24
-   |
-LL |     use std::convert::{TryFrom, TryInto};
-   |                        ^^^^^^^
-  --> $SRC_DIR/std/src/prelude/mod.rs:LL:COL
-   |
-   = note: the item `TryFrom` is already defined here
-
-error: the item `TryInto` is imported redundantly
-  --> $DIR/suggest-remove-issue-121315.rs:14:33
-   |
-LL |     use std::convert::{TryFrom, TryInto};
-   |                                 ^^^^^^^
-  --> $SRC_DIR/std/src/prelude/mod.rs:LL:COL
-   |
-   = note: the item `TryInto` is already defined here
-
 error: unused import: `AsMut`
-  --> $DIR/suggest-remove-issue-121315.rs:24:24
+  --> $DIR/suggest-remove-issue-121315.rs:25:24
    |
 LL |     use std::convert::{AsMut, Into};
    |                        ^^^^^
-
-error: the item `Into` is imported redundantly
-  --> $DIR/suggest-remove-issue-121315.rs:24:31
    |
-LL |     use std::convert::{AsMut, Into};
-   |                               ^^^^
-  --> $SRC_DIR/std/src/prelude/mod.rs:LL:COL
+note: the lint level is defined here
+  --> $DIR/suggest-remove-issue-121315.rs:3:9
    |
-   = note: the item `Into` is already defined here
+LL | #![deny(unused_imports)]
+   |         ^^^^^^^^^^^^^^
 
 error: unused import: `From`
-  --> $DIR/suggest-remove-issue-121315.rs:33:24
+  --> $DIR/suggest-remove-issue-121315.rs:34:24
    |
 LL |     use std::convert::{From, Infallible};
    |                        ^^^^
 
-error: aborting due to 6 previous errors
+error: aborting due to 2 previous errors
 

tests/ui/lint/unused/issue-59896.rs

@@ -1,9 +1,10 @@
+//@ check-pass
 #![deny(unused_imports)]
 
 struct S;
 
 fn main() {
-    use S;  //~ ERROR the item `S` is imported redundantly
+    use S;  //FIXME(unused_imports): ~ ERROR the item `S` is imported redundantly
 
     let _s = S;
 }

tests/ui/lint/use-redundant/use-redundant-glob-parent.rs

@@ -9,7 +9,7 @@ pub mod bar {
 use bar::*;
 
 pub fn warning() -> Foo {
-    use bar::Foo; //~ WARNING imported redundantly
+    use bar::Foo; //FIXME(unused_imports): ~ WARNING imported redundantly
     Foo(Bar('a'))
 }
 

tests/ui/lint/use-redundant/use-redundant-glob.rs

@@ -8,7 +8,7 @@ pub mod bar {
 
 pub fn warning() -> bar::Foo {
     use bar::*;
-    use bar::Foo; //~ WARNING imported redundantly
+    use bar::Foo; //FIXME(unused_imports): ~ WARNING imported redundantly
     Foo(Bar('a'))
 }
 

tests/ui/lint/use-redundant/use-redundant-issue-71450.rs

@@ -23,7 +23,8 @@ mod foo {
 fn main() {
 
     {
-        use std::string::String; //~ WARNING the item `String` is imported redundantly
+        use std::string::String;
+        //FIXME(unused_imports): ~^ WARNING the item `String` is imported redundantly
         // 'String' from 'std::string::String'.
         let s = String::new();
         println!("{}", s);

tests/ui/lint/use-redundant/use-redundant-prelude-rust-2015.rs

@@ -2,11 +2,15 @@
 #![warn(unused_imports)]
 
 
-use std::option::Option::Some;//~ WARNING the item `Some` is imported redundantly
-use std::option::Option::None; //~ WARNING the item `None` is imported redundantly
+use std::option::Option::Some;
+//FIXME(unused_imports): ~^ WARNING the item `Some` is imported redundantly
+use std::option::Option::None;
+//FIXME(unused_imports): ~ WARNING the item `None` is imported redundantly
 
-use std::result::Result::Ok;//~ WARNING the item `Ok` is imported redundantly
-use std::result::Result::Err;//~ WARNING the item `Err` is imported redundantly
+use std::result::Result::Ok;
+//FIXME(unused_imports): ~^ WARNING the item `Ok` is imported redundantly
+use std::result::Result::Err;
+//FIXME(unused_imports): ~^ WARNING the item `Err` is imported redundantly
 use std::convert::{TryFrom, TryInto};
 
 fn main() {