Distinguish between imported and defined items

Author: fabric-and-ink

src/librustc/lint/builtin.rs

@@ -488,7 +488,7 @@ pub enum BuiltinLintDiagnostics {
     UnknownCrateTypes(Span, String, String),
     UnusedImports(String, Vec<(Span, String)>),
     NestedImplTrait { outer_impl_trait_span: Span, inner_impl_trait_span: Span },
-    RedundantImport(Vec<Span>, ast::Ident),
+    RedundantImport(Vec<(Span, bool)>, ast::Ident),
 }
 
 impl BuiltinLintDiagnostics {
@@ -586,10 +586,11 @@ impl BuiltinLintDiagnostics {
                 db.span_label(inner_impl_trait_span, "nested `impl Trait` here");
             }
             BuiltinLintDiagnostics::RedundantImport(spans, ident) => {
-                for span in spans {
+                for (span, is_imported) in spans {
+                    let introduced = if is_imported { "imported" } else { "defined" };
                     db.span_label(
                         span,
-                        format!("the item `{}` was already imported here", ident)
+                        format!("the item `{}` was {} here", ident, introduced)
                     );
                 }
             }

src/librustc_resolve/resolve_imports.rs

@@ -1298,7 +1298,8 @@ impl<'a, 'b:'a> ImportResolver<'a, 'b> {
             ) {
                 Ok(other_binding) => {
                     is_redundant[ns] = Some(binding.def() == other_binding.def());
-                    redundant_span[ns] = Some(other_binding.span);
+                    redundant_span[ns] =
+                        Some((other_binding.span, other_binding.is_import()));
                 }
                 Err(_) => is_redundant[ns] = Some(false)
             }

src/test/ui/lint/use-redundant.stderr

@@ -2,7 +2,7 @@ warning: the item `Bar` is imported redundantly
   --> $DIR/use-redundant.rs:14:9
    |
 LL | use crate::foo::Bar;
-   |     --------------- the item `Bar` was already imported here
+   |     --------------- the item `Bar` was imported here
 ...
 LL |     use crate::foo::Bar;
    |         ^^^^^^^^^^^^^^^