Auto merge of #33619 - jonathandturner:improve_structured_errors, r=nikomatsakis

Batch of improvements to errors for new error format

This is a batch of improvements to existing errors to help get the most out of the new error format.

* Added labels to primary spans (^^^) for a set of errors that didn't currently have them
* Highlight the source blue under the secondary notes for better readability
* Move some of the "Note:" into secondary spans+labels
* Fix span_label to take &mut instead, which makes it work the same as other methods in that set

22 files changed, 87 insertions, 45 deletions

diff --git a/src/test/compile-fail/augmented-assignments.rs b/src/test/compile-fail/augmented-assignments.rs
index 8ac6b419295..92a8b10669c 100644
--- a/src/test/compile-fail/augmented-assignments.rs
+++ b/src/test/compile-fail/augmented-assignments.rs
@@ -27,7 +27,9 @@ fn main() {
     x;  //~ value moved here
 
     let y = Int(2);
+    //~^use `mut y` here to make mutable
     y   //~ error: cannot borrow immutable local variable `y` as mutable
+        //~| cannot borrow
     +=
     Int(1);
 }
diff --git a/src/test/compile-fail/blind-item-block-middle.rs b/src/test/compile-fail/blind-item-block-middle.rs
index 930f769771d..287eab7a563 100644
--- a/src/test/compile-fail/blind-item-block-middle.rs
+++ b/src/test/compile-fail/blind-item-block-middle.rs
@@ -12,6 +12,6 @@ mod foo { pub struct bar; }
 
 fn main() {
     let bar = 5;
-    //~^ ERROR declaration of `bar` shadows an enum variant or unit-like struct in scope
+    //~^ ERROR cannot be named the same
     use foo::bar;
 }
diff --git a/src/test/compile-fail/blind-item-item-shadow.rs b/src/test/compile-fail/blind-item-item-shadow.rs
index b08c78e9060..853282ff014 100644
--- a/src/test/compile-fail/blind-item-item-shadow.rs
+++ b/src/test/compile-fail/blind-item-item-shadow.rs
@@ -10,6 +10,8 @@
 
 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
+use foo::foo;
+//~^ ERROR a module named `foo` has already been defined in this module
+//~| was already imported
 
 fn main() {}
diff --git a/src/test/compile-fail/borrowck/borrowck-box-insensitivity.rs b/src/test/compile-fail/borrowck/borrowck-box-insensitivity.rs
index bde3212c5bc..3fd71f71564 100644
--- a/src/test/compile-fail/borrowck/borrowck-box-insensitivity.rs
+++ b/src/test/compile-fail/borrowck/borrowck-box-insensitivity.rs
@@ -61,7 +61,9 @@ fn move_after_borrow() {
     let a: Box<_> = box B { x: box 0, y: box 1 };
     let _x = &a.x;
     //~^ NOTE borrow of `a.x` occurs here
-    let _y = a.y; //~ ERROR cannot move
+    let _y = a.y;
+    //~^ ERROR cannot move
+    //~| move out of
 }
 
 fn copy_after_mut_borrow() {
@@ -75,7 +77,9 @@ fn move_after_mut_borrow() {
     let mut a: Box<_> = box B { x: box 0, y: box 1 };
     let _x = &mut a.x;
     //~^ NOTE borrow of `a.x` occurs here
-    let _y = a.y; //~ ERROR cannot move
+    let _y = a.y;
+    //~^ ERROR cannot move
+    //~| move out of
 }
 
 fn borrow_after_mut_borrow() {
@@ -127,7 +131,9 @@ fn move_after_borrow_nested() {
     let a: Box<_> = box D { x: box A { x: box 0, y: 1 }, y: box 2 };
     let _x = &a.x.x;
     //~^ borrow of `a.x.x` occurs here
-    let _y = a.y; //~ ERROR cannot move
+    let _y = a.y;
+    //~^ ERROR cannot move
+    //~| move out of
 }
 
 fn copy_after_mut_borrow_nested() {
@@ -141,7 +147,9 @@ fn move_after_mut_borrow_nested() {
     let mut a: Box<_> = box D { x: box A { x: box 0, y: 1 }, y: box 2 };
     let _x = &mut a.x.x;
     //~^ NOTE borrow of `a.x.x` occurs here
-    let _y = a.y; //~ ERROR cannot move
+    let _y = a.y;
+    //~^ ERROR cannot move
+    //~| move out of
 }
 
 fn borrow_after_mut_borrow_nested() {
diff --git a/src/test/compile-fail/borrowck/borrowck-let-suggestion-suffixes.rs b/src/test/compile-fail/borrowck/borrowck-let-suggestion-suffixes.rs
index f551a2aa811..02aa771c787 100644
--- a/src/test/compile-fail/borrowck/borrowck-let-suggestion-suffixes.rs
+++ b/src/test/compile-fail/borrowck/borrowck-let-suggestion-suffixes.rs
@@ -26,6 +26,7 @@ fn f() {
 
     v3.push(&'x');           // statement 6
     //~^ ERROR borrowed value does not live long enough
+    //~| does not live long enough
     //~| NOTE ...but borrowed value is only valid for the statement
     //~| HELP consider using a `let` binding to increase its lifetime
 
@@ -36,6 +37,7 @@ fn f() {
 
         v4.push(&'y');
         //~^ ERROR borrowed value does not live long enough
+        //~| does not live long enough
         //~| NOTE ...but borrowed value is only valid for the statement
         //~| HELP consider using a `let` binding to increase its lifetime
 
@@ -46,6 +48,7 @@ fn f() {
 
     v5.push(&'z');
     //~^ ERROR borrowed value does not live long enough
+    //~| does not live long enough
     //~| NOTE ...but borrowed value is only valid for the statement
     //~| HELP consider using a `let` binding to increase its lifetime
 
diff --git a/src/test/compile-fail/borrowck/borrowck-let-suggestion.rs b/src/test/compile-fail/borrowck/borrowck-let-suggestion.rs
index 7e9d448275d..866e72f1a52 100644
--- a/src/test/compile-fail/borrowck/borrowck-let-suggestion.rs
+++ b/src/test/compile-fail/borrowck/borrowck-let-suggestion.rs
@@ -9,10 +9,12 @@
 // except according to those terms.
 
 fn f() {
-    let x = [1].iter(); //~ ERROR borrowed value does not live long enough
-                         //~^ NOTE reference must be valid for the block suffix following statement
-                         //~^^ HELP consider using a `let` binding to increase its lifetime
-                         //~^^^ NOTE ...but borrowed value is only valid for the statement at 12:4
+    let x = [1].iter();
+    //~^ ERROR borrowed value does not live long enough
+    //~|does not live long enough
+    //~| NOTE reference must be valid for the block suffix following statement
+    //~| HELP consider using a `let` binding to increase its lifetime
+    //~| NOTE ...but borrowed value is only valid for the statement at 12:4
 }
 
 fn main() {
diff --git a/src/test/compile-fail/borrowck/borrowck-move-error-with-note.rs b/src/test/compile-fail/borrowck/borrowck-move-error-with-note.rs
index e4b9fb26711..ffa7d192556 100644
--- a/src/test/compile-fail/borrowck/borrowck-move-error-with-note.rs
+++ b/src/test/compile-fail/borrowck/borrowck-move-error-with-note.rs
@@ -19,6 +19,7 @@ enum Foo {
 fn blah() {
     let f = &Foo::Foo1(box 1, box 2);
     match *f {             //~ ERROR cannot move out of
+                           //~| move occurs here
         Foo::Foo1(num1,         //~ NOTE attempting to move value to here
                   num2) => (),  //~ NOTE and here
         Foo::Foo2(num) => (),   //~ NOTE and here
@@ -37,6 +38,7 @@ impl Drop for S {
 fn move_in_match() {
     match (S {f: "foo".to_string(), g: "bar".to_string()}) {
         S {         //~ ERROR cannot move out of type `S`, which defines the `Drop` trait
+        //~| can not move out of here
             f: _s,  //~ NOTE attempting to move value to here
             g: _t   //~ NOTE and here
         } => {}
@@ -53,6 +55,7 @@ fn free<T>(_: T) {}
 fn blah2() {
     let a = &A { a: box 1 };
     match a.a {           //~ ERROR cannot move out of
+                          //~| move occurs here
         n => {            //~ NOTE attempting to move value to here
             free(n)
         }
diff --git a/src/test/compile-fail/borrowck/borrowck-move-out-of-vec-tail.rs b/src/test/compile-fail/borrowck/borrowck-move-out-of-vec-tail.rs
index d9a2f89a9e2..2f1c69d0d7d 100644
--- a/src/test/compile-fail/borrowck/borrowck-move-out-of-vec-tail.rs
+++ b/src/test/compile-fail/borrowck/borrowck-move-out-of-vec-tail.rs
@@ -27,10 +27,12 @@ pub fn main() {
     match x {
         [_, tail..] => {
             match tail {
-                [Foo { string: a }, //~ ERROR cannot move out of borrowed content
+                [Foo { string: a },
+                //~^ ERROR cannot move out of borrowed content
+                //~| move occurs here
+                //~| attempting to move value to here
                  Foo { string: b }] => {
-                    //~^^ NOTE attempting to move value to here
-                    //~^^ NOTE and here
+                    //~^ NOTE and here
                 }
                 _ => {
                     unreachable!();
diff --git a/src/test/compile-fail/borrowck/borrowck-vec-pattern-nesting.rs b/src/test/compile-fail/borrowck/borrowck-vec-pattern-nesting.rs
index 1a21b03a457..1c63b458e62 100644
--- a/src/test/compile-fail/borrowck/borrowck-vec-pattern-nesting.rs
+++ b/src/test/compile-fail/borrowck/borrowck-vec-pattern-nesting.rs
@@ -19,6 +19,7 @@ fn a() {
         [box ref _a, _, _] => {
         //~^ borrow of `vec[..]` occurs here
             vec[0] = box 4; //~ ERROR cannot assign
+            //~^ assignment to `vec[..]` occurs here
         }
     }
 }
@@ -30,6 +31,7 @@ fn b() {
         [_b..] => {
         //~^ borrow of `vec[..]` occurs here
             vec[0] = box 4; //~ ERROR cannot assign
+            //~^ assignment to `vec[..]` occurs here
         }
     }
 }
@@ -39,8 +41,9 @@ fn c() {
     let vec: &mut [Box<isize>] = &mut vec;
     match vec {
         [_a,         //~ ERROR cannot move out
-         _b..] => {  //~^ NOTE attempting to move value to here
-
+        //~| move occurs here
+        //~| attempting to move value to here
+         _b..] => {
             // Note: `_a` is *moved* here, but `b` is borrowing,
             // hence illegal.
             //
@@ -51,6 +54,7 @@ fn c() {
     }
     let a = vec[0]; //~ ERROR cannot move out
     //~^ NOTE attempting to move value to here
+    //~| can not move out of here
 }
 
 fn d() {
@@ -58,11 +62,13 @@ fn d() {
     let vec: &mut [Box<isize>] = &mut vec;
     match vec {
         [_a..,     //~ ERROR cannot move out
+        //~^ move occurs here
          _b] => {} //~ NOTE attempting to move value to here
         _ => {}
     }
     let a = vec[0]; //~ ERROR cannot move out
     //~^ NOTE attempting to move value to here
+    //~| can not move out of here
 }
 
 fn e() {
@@ -70,13 +76,15 @@ fn e() {
     let vec: &mut [Box<isize>] = &mut vec;
     match vec {
         [_a, _b, _c] => {}  //~ ERROR cannot move out
-        //~^ NOTE attempting to move value to here
-        //~^^ NOTE and here
-        //~^^^ NOTE and here
+        //~| move occurs here
+        //~| NOTE attempting to move value to here
+        //~| NOTE and here
+        //~| NOTE and here
         _ => {}
     }
     let a = vec[0]; //~ ERROR cannot move out
     //~^ NOTE attempting to move value to here
+    //~| can not move out of here
 }
 
 fn main() {}
diff --git a/src/test/compile-fail/const-pattern-irrefutable.rs b/src/test/compile-fail/const-pattern-irrefutable.rs
index 0be1e974e7d..392f391fb51 100644
--- a/src/test/compile-fail/const-pattern-irrefutable.rs
+++ b/src/test/compile-fail/const-pattern-irrefutable.rs
@@ -13,16 +13,16 @@ mod foo {
     pub const d: u8 = 2;
 }
 
-use foo::b as c; //~ NOTE constant imported here
-use foo::d; //~ NOTE constant imported here
+use foo::b as c; //~ NOTE is imported here
+use foo::d; //~ NOTE is imported here
 
-const a: u8 = 2; //~ NOTE constant defined here
+const a: u8 = 2; //~ NOTE is defined here
 
 fn main() {
-    let a = 4; //~ ERROR variable bindings cannot
-               //~^ NOTE there already is a constant in scope
-    let c = 4; //~ ERROR variable bindings cannot
-               //~^ NOTE there already is a constant in scope
-    let d = 4; //~ ERROR variable bindings cannot
-               //~^ NOTE there already is a constant in scope
+    let a = 4; //~ ERROR let variables cannot
+               //~^ NOTE cannot be named the same as a const variable
+    let c = 4; //~ ERROR let variables cannot
+               //~^ NOTE cannot be named the same as a const variable
+    let d = 4; //~ ERROR let variables cannot
+               //~^ NOTE cannot be named the same as a const variable
 }
diff --git a/src/test/compile-fail/enum-in-scope.rs b/src/test/compile-fail/enum-in-scope.rs
index 7be06ec7de8..6dffd1999d7 100644
--- a/src/test/compile-fail/enum-in-scope.rs
+++ b/src/test/compile-fail/enum-in-scope.rs
@@ -11,5 +11,5 @@
 struct hello(isize);
 
 fn main() {
-    let hello = 0; //~ERROR declaration of `hello` shadows
+    let hello = 0; //~ERROR cannot be named the same
 }
diff --git a/src/test/compile-fail/issue-19498.rs b/src/test/compile-fail/issue-19498.rs
index 87b79b5cd67..2e2115b7110 100644
--- a/src/test/compile-fail/issue-19498.rs
+++ b/src/test/compile-fail/issue-19498.rs
@@ -11,11 +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
 pub mod B {} //~ ERROR a module named `B` has already been imported in this module
-
+//~| `B` was 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
 }
 
 fn main() {}
diff --git a/src/test/compile-fail/issue-23716.rs b/src/test/compile-fail/issue-23716.rs
index 31604e2fdd3..b0d36610b7a 100644
--- a/src/test/compile-fail/issue-23716.rs
+++ b/src/test/compile-fail/issue-23716.rs
@@ -13,6 +13,7 @@ static foo: i32 = 0;
 
 fn bar(foo: i32) {}
 //~^ ERROR static variables cannot be referenced in a pattern, use a `const` instead
+//~| static variable used in pattern
 
 mod submod {
     pub static answer: i32 = 42;
@@ -23,6 +24,6 @@ use self::submod::answer;
 
 fn question(answer: i32) {}
 //~^ ERROR static variables cannot be referenced in a pattern, use a `const` instead
-
+//~| static variable used in pattern
 fn main() {
 }
diff --git a/src/test/compile-fail/issue-24081.rs b/src/test/compile-fail/issue-24081.rs
index 94fb3008289..188716c5e93 100644
--- a/src/test/compile-fail/issue-24081.rs
+++ b/src/test/compile-fail/issue-24081.rs
@@ -15,9 +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
 struct Sub { x: f32 } //~ ERROR a trait named `Sub` has already been imported in this module
+//~| was already imported
 enum Mul { A, B } //~ ERROR a trait named `Mul` has already been imported in this module
+//~| was already imported
 mod Div { } //~ ERROR a trait named `Div` has already been imported in this module
+//~| was already imported
 trait Rem {  } //~ ERROR a trait named `Rem` has already been imported in this module
+//~| was already imported
 
 fn main() {}
diff --git a/src/test/compile-fail/issue-27033.rs b/src/test/compile-fail/issue-27033.rs
index a729cf95a7b..b0904dfeaa7 100644
--- a/src/test/compile-fail/issue-27033.rs
+++ b/src/test/compile-fail/issue-27033.rs
@@ -10,11 +10,11 @@
 
 fn main() {
     match Some(1) {
-        None @ _ => {} //~ ERROR declaration of `None` shadows an enum variant
+        None @ _ => {} //~ ERROR cannot be named the same
     };
     const C: u8 = 1;
     match 1 {
-        C @ 2 => { //~ ERROR variable bindings cannot shadow constants
+        C @ 2 => { //~ ERROR cannot be named the same
             println!("{}", C);
         }
         _ => {}
diff --git a/src/test/compile-fail/issue-3907.rs b/src/test/compile-fail/issue-3907.rs
index 1dbf211b269..c99ff1813e0 100644
--- a/src/test/compile-fail/issue-3907.rs
+++ b/src/test/compile-fail/issue-3907.rs
@@ -11,14 +11,14 @@
 // aux-build:issue_3907.rs
 extern crate issue_3907;
 
-type Foo = issue_3907::Foo; //~ NOTE: type defined here
+type Foo = issue_3907::Foo; //~ NOTE: type aliases cannot be used for traits
 
 struct S {
     name: isize
 }
 
 impl Foo for S { //~ ERROR: `Foo` is not a trait
-    //~^ NOTE: `type` aliases cannot be used for traits
+    //~| `Foo` is not a trait
     fn bar() { }
 }
 
diff --git a/src/test/compile-fail/issue-5035.rs b/src/test/compile-fail/issue-5035.rs
index dabeb503841..a186a399a11 100644
--- a/src/test/compile-fail/issue-5035.rs
+++ b/src/test/compile-fail/issue-5035.rs
@@ -9,7 +9,8 @@
 // except according to those terms.
 
 trait I {}
-type K = I; //~ NOTE: type defined here
+type K = I;
+//~^ NOTE: aliases cannot be used for traits
 impl K for isize {} //~ ERROR: `K` is not a trait
-//~^ NOTE: `type` aliases cannot be used for traits
+//~| is not a trait
 fn main() {}
diff --git a/src/test/compile-fail/moves-based-on-type-block-bad.rs b/src/test/compile-fail/moves-based-on-type-block-bad.rs
index a1e876594c2..1fd69e2dbfe 100644
--- a/src/test/compile-fail/moves-based-on-type-block-bad.rs
+++ b/src/test/compile-fail/moves-based-on-type-block-bad.rs
@@ -32,6 +32,7 @@ fn main() {
     loop {
         f(&s, |hellothere| {
             match hellothere.x { //~ ERROR cannot move out
+                                 //~| move occurs here
                 box E::Foo(_) => {}
                 box E::Bar(x) => println!("{}", x.to_string()), //~ NOTE attempting to move value to here
                 box E::Baz => {}
diff --git a/src/test/compile-fail/mut-suggestion.rs b/src/test/compile-fail/mut-suggestion.rs
index efd796e1195..242ad7aee8d 100644
--- a/src/test/compile-fail/mut-suggestion.rs
+++ b/src/test/compile-fail/mut-suggestion.rs
@@ -17,14 +17,16 @@ impl S {
 }
 
 fn func(arg: S) {
-    //~^ HELP use `mut` as shown
-    //~| SUGGESTION fn func(mut arg: S) {
-    arg.mutate(); //~ ERROR cannot borrow immutable argument
+    //~^ here to make mutable
+    arg.mutate();
+    //~^ ERROR cannot borrow immutable argument
+    //~| cannot borrow mutably
 }
 
 fn main() {
     let local = S;
-    //~^ HELP use `mut` as shown
-    //~| SUGGESTION let mut local = S;
-    local.mutate(); //~ ERROR cannot borrow immutable local variable
+    //~^ here to make mutable
+    local.mutate();
+    //~^ ERROR cannot borrow immutable local variable
+    //~| cannot borrow mutably
 }
diff --git a/src/test/compile-fail/name-clash-nullary.rs b/src/test/compile-fail/name-clash-nullary.rs
index 1250318a729..662bb7bfe57 100644
--- a/src/test/compile-fail/name-clash-nullary.rs
+++ b/src/test/compile-fail/name-clash-nullary.rs
@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// error-pattern:declaration of `None` shadows
+// error-pattern:cannot be named the same
 use std::option::*;
 
 fn main() {
diff --git a/src/test/compile-fail/pat-shadow-in-nested-binding.rs b/src/test/compile-fail/pat-shadow-in-nested-binding.rs
index 526e4c16187..4a8513e10d7 100644
--- a/src/test/compile-fail/pat-shadow-in-nested-binding.rs
+++ b/src/test/compile-fail/pat-shadow-in-nested-binding.rs
@@ -11,5 +11,5 @@
 struct foo(usize);
 
 fn main() {
-    let (foo, _) = (2, 3); //~ ERROR declaration of `foo` shadows
+    let (foo, _) = (2, 3); //~ ERROR `foo` cannot be named the same as
 }
diff --git a/src/test/compile-fail/resolve-conflict-item-vs-import.rs b/src/test/compile-fail/resolve-conflict-item-vs-import.rs
index dbd1ecf44fd..5a068ce4214 100644
--- a/src/test/compile-fail/resolve-conflict-item-vs-import.rs
+++ b/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
 fn main() {
 }