resolve: clean up diagnostics for name conflicts.

Author: jseyfried

src/librustc_resolve/lib.rs

@@ -3156,40 +3156,19 @@ impl<'a> Resolver<'a> {
         };
 
         let mut err = match (old_binding.is_extern_crate(), binding.is_extern_crate()) {
-            (true, true) => {
-                let mut e = struct_span_err!(self.session, span, E0259, "{}", msg);
-                e.span_label(span, &format!("`{}` was already imported", name));
-                e
-            },
-            (true, _) | (_, true) if binding.is_import() && old_binding.is_import() => {
-                let mut e = struct_span_err!(self.session, span, E0254, "{}", msg);
-                e.span_label(span, &"already imported");
-                e
-            },
-            (true, _) | (_, true) => {
-                let mut e = struct_span_err!(self.session, span, E0260, "{}", msg);
-                e.span_label(span, &format!("`{}` already imported", name));
-                e
+            (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
+            (true, _) | (_, true) => match binding.is_import() && old_binding.is_import() {
+                true => struct_span_err!(self.session, span, E0254, "{}", msg),
+                false => struct_span_err!(self.session, span, E0260, "{}", msg),
             },
             _ => match (old_binding.is_import(), binding.is_import()) {
-                (false, false) => {
-                    let mut e = struct_span_err!(self.session, span, E0428, "{}", msg);
-                    e.span_label(span, &format!("already defined"));
-                    e
-                },
-                (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));
-                    e
-                }
+                (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
+                (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
+                _ => struct_span_err!(self.session, span, E0255, "{}", msg),
             },
         };
 
+        err.span_label(span, &format!("`{}` already {}", name, participle));
         if old_binding.span != syntax_pos::DUMMY_SP {
             err.span_label(old_binding.span, &format!("previous {} of `{}` here", noun, name));
         }

src/test/compile-fail/E0259.rs

@@ -15,6 +15,6 @@ extern crate collections;
 
 extern crate libc as collections;
 //~^ ERROR E0259
-//~| NOTE `collections` was already imported
+//~| NOTE `collections` already imported
 
 fn main() {}

src/test/compile-fail/blind-item-item-shadow.rs

@@ -12,6 +12,6 @@ mod foo { pub mod foo {  } } //~ NOTE previous definition of `foo` here
 
 use foo::foo;
 //~^ ERROR a module named `foo` has already been defined in this module
-//~| was already imported
+//~| `foo` already defined
 
 fn main() {}

src/test/compile-fail/issue-19498.rs

@@ -11,13 +11,13 @@
 use self::A; //~ NOTE previous import of `A` here
 use self::B; //~ NOTE previous import of `B` here
 mod A {} //~ ERROR a module named `A` has already been imported in this module
-//~| `A` was already imported
+//~| `A` already imported
 pub mod B {} //~ ERROR a module named `B` has already been imported in this module
-//~| `B` was already imported
+//~| `B` already imported
 mod C {
     use C::D; //~ NOTE previous import of `D` here
     mod D {} //~ ERROR a module named `D` has already been imported in this module
-    //~| `D` was already imported
+    //~| `D` already imported
 }
 
 fn main() {}

src/test/compile-fail/issue-24081.rs

@@ -15,14 +15,14 @@ use std::ops::Div; //~ NOTE previous import
 use std::ops::Rem; //~ NOTE previous import
 
 type Add = bool; //~ ERROR a trait named `Add` has already been imported in this module
-//~| was already imported
+//~| `Add` already imported
 struct Sub { x: f32 } //~ ERROR a trait named `Sub` has already been imported in this module
-//~| was already imported
+//~| `Sub` already imported
 enum Mul { A, B } //~ ERROR a trait named `Mul` has already been imported in this module
-//~| was already imported
+//~| `Mul` already imported
 mod Div { } //~ ERROR a trait named `Div` has already been imported in this module
-//~| was already imported
+//~| `Div` already imported
 trait Rem {  } //~ ERROR a trait named `Rem` has already been imported in this module
-//~| was already imported
+//~| `Rem` already imported
 
 fn main() {}

src/test/compile-fail/resolve-conflict-item-vs-import.rs

@@ -13,6 +13,6 @@ use std::mem::transmute;
 
 fn transmute() {}
 //~^ ERROR a value named `transmute` has already been imported in this module
-//~| was already imported
+//~| `transmute` already imported
 fn main() {
 }