Silence unused_imports lint for redundant imports

(cherry picked from commit 0db2a40)

Author: compiler-errors

compiler/rustc_resolve/src/imports.rs

@@ -1368,13 +1368,15 @@ 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-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-issue-121915-2015.stderr

@@ -1,9 +1,10 @@
+//@ check-pass
 //@ compile-flags: --extern aux_issue_121915 --edition 2018
 //@ aux-build: aux-issue-121915.rs
 
 #[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-issue-121915.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/redundant-import-issue-121915.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/imports/suggest-remove-issue-121315.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;
 }