Auto merge of #35362 - medzin:E0252, r=GuillaumeGomez

Updated error message E0252

Fixes #35306 as part of #35233.

r? @GuillaumeGomez

src/librustc_resolve/lib.rs

@@ -3375,7 +3375,11 @@ impl<'a> Resolver<'a> {
             (true, _) | (_, true) => struct_span_err!(self.session, span, E0260, "{}", msg),
             _ => match (old_binding.is_import(), binding.is_import()) {
                 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
-                (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
+                (true, true) => {
+                    let mut e = struct_span_err!(self.session, span, E0252, "{}", msg);
+                    e.span_label(span, &format!("already imported"));
+                    e
+                },
                 _ => {
                     let mut e = struct_span_err!(self.session, span, E0255, "{}", msg);
                     e.span_label(span, &format!("`{}` was already imported", name));

src/test/compile-fail/double-import.rs

@@ -7,8 +7,6 @@
 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
-#![feature(no_core)]
-#![no_core]
 
 // This tests that conflicting imports shows both `use` lines
 // when reporting the error.
@@ -23,5 +21,6 @@ mod sub2 {
 
 use sub1::foo; //~ NOTE previous import of `foo` here
 use sub2::foo; //~ ERROR a value named `foo` has already been imported in this module [E0252]
+               //~| NOTE already imported
 
 fn main() {}

src/test/compile-fail/issue-26886.rs

@@ -11,7 +11,9 @@
 use std::sync::{self, Arc}; //~ NOTE previous import
                             //~^ NOTE previous import
 use std::sync::Arc; //~ ERROR a type named
+                    //~| NOTE already imported
 use std::sync; //~ ERROR a module named
+               //~| NOTE already imported
 
 fn main() {
 }

src/test/compile-fail/use-mod.rs

@@ -15,7 +15,8 @@ use foo::bar::{
     Bar,
     self
 //~^ NOTE another `self` import appears here
-//~^^ ERROR a module named `bar` has already been imported in this module
+//~| ERROR a module named `bar` has already been imported in this module
+//~| NOTE already imported
 };
 
 use {self};