Rollup merge of #38171 - jseyfried:cleanup, r=nrc

Miscellaneous cleanup/refactoring in `resolve` and `syntax::ext`

r? @nrc

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() {
 }