Be more hygenic with spans

compiler/rustc_mir_build/src/thir/pattern/check_match.rs

@@ -821,16 +821,17 @@ fn non_exhaustive_match<'p, 'tcx>(
             ));
         }
         [only] => {
-            let pre_indentation = if let (Some(snippet), true) = (
-                sm.indentation_before(only.span),
-                sm.is_multiline(sp.shrink_to_hi().with_hi(only.span.lo())),
-            ) {
-                format!("\n{}", snippet)
+            let (pre_indentation, is_multiline) = if let Some(snippet) = sm.indentation_before(only.span)
+                && let Ok(with_trailing) = sm.span_extend_while(only.span, |c| c.is_whitespace() || c == ',')
+                && sm.is_multiline(with_trailing)
+            {
+                (format!("\n{}", snippet), true)
             } else {
-                " ".to_string()
+                (" ".to_string(), false)
             };
             let comma = if matches!(only.body.kind, hir::ExprKind::Block(..))
                 && only.span.eq_ctxt(only.body.span)
+                && is_multiline
             {
                 ""
             } else {

src/test/ui/pattern/usefulness/integer-ranges/exhaustiveness.stderr

@@ -7,9 +7,8 @@ LL |     m!(0u8, 0..255);
    = note: the matched value is of type `u8`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL ~         match $s { $($t)+ => {}
-LL ~         u8::MAX => todo!() }
-   |
+LL |         match $s { $($t)+ => {}, u8::MAX => todo!() }
+   |                                ++++++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `u8::MAX` not covered
   --> $DIR/exhaustiveness.rs:48:8
@@ -20,9 +19,8 @@ LL |     m!(0u8, 0..=254);
    = note: the matched value is of type `u8`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL ~         match $s { $($t)+ => {}
-LL ~         u8::MAX => todo!() }
-   |
+LL |         match $s { $($t)+ => {}, u8::MAX => todo!() }
+   |                                ++++++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `0_u8` not covered
   --> $DIR/exhaustiveness.rs:49:8
@@ -33,9 +31,8 @@ LL |     m!(0u8, 1..=255);
    = note: the matched value is of type `u8`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL ~         match $s { $($t)+ => {}
-LL ~         0_u8 => todo!() }
-   |
+LL |         match $s { $($t)+ => {}, 0_u8 => todo!() }
+   |                                +++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `42_u8` not covered
   --> $DIR/exhaustiveness.rs:50:8
@@ -46,9 +43,8 @@ LL |     m!(0u8, 0..42 | 43..=255);
    = note: the matched value is of type `u8`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL ~         match $s { $($t)+ => {}
-LL ~         42_u8 => todo!() }
-   |
+LL |         match $s { $($t)+ => {}, 42_u8 => todo!() }
+   |                                ++++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `i8::MAX` not covered
   --> $DIR/exhaustiveness.rs:51:8
@@ -59,9 +55,8 @@ LL |     m!(0i8, -128..127);
    = note: the matched value is of type `i8`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL ~         match $s { $($t)+ => {}
-LL ~         i8::MAX => todo!() }
-   |
+LL |         match $s { $($t)+ => {}, i8::MAX => todo!() }
+   |                                ++++++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `i8::MAX` not covered
   --> $DIR/exhaustiveness.rs:52:8
@@ -72,9 +67,8 @@ LL |     m!(0i8, -128..=126);
    = note: the matched value is of type `i8`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL ~         match $s { $($t)+ => {}
-LL ~         i8::MAX => todo!() }
-   |
+LL |         match $s { $($t)+ => {}, i8::MAX => todo!() }
+   |                                ++++++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `i8::MIN` not covered
   --> $DIR/exhaustiveness.rs:53:8
@@ -85,9 +79,8 @@ LL |     m!(0i8, -127..=127);
    = note: the matched value is of type `i8`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL ~         match $s { $($t)+ => {}
-LL ~         i8::MIN => todo!() }
-   |
+LL |         match $s { $($t)+ => {}, i8::MIN => todo!() }
+   |                                ++++++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `0_i8` not covered
   --> $DIR/exhaustiveness.rs:54:11
@@ -111,9 +104,8 @@ LL |     m!(0u128, 0..=ALMOST_MAX);
    = note: the matched value is of type `u128`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL ~         match $s { $($t)+ => {}
-LL ~         u128::MAX => todo!() }
-   |
+LL |         match $s { $($t)+ => {}, u128::MAX => todo!() }
+   |                                ++++++++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `5_u128..=u128::MAX` not covered
   --> $DIR/exhaustiveness.rs:60:8
@@ -124,9 +116,8 @@ LL |     m!(0u128, 0..=4);
    = note: the matched value is of type `u128`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL ~         match $s { $($t)+ => {}
-LL ~         5_u128..=u128::MAX => todo!() }
-   |
+LL |         match $s { $($t)+ => {}, 5_u128..=u128::MAX => todo!() }
+   |                                +++++++++++++++++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `0_u128` not covered
   --> $DIR/exhaustiveness.rs:61:8
@@ -137,9 +128,8 @@ LL |     m!(0u128, 1..=u128::MAX);
    = note: the matched value is of type `u128`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL ~         match $s { $($t)+ => {}
-LL ~         0_u128 => todo!() }
-   |
+LL |         match $s { $($t)+ => {}, 0_u128 => todo!() }
+   |                                +++++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `(126_u8..=127_u8, false)` not covered
   --> $DIR/exhaustiveness.rs:69:11

src/test/ui/pattern/usefulness/integer-ranges/pointer-sized-int.deny.stderr

@@ -39,9 +39,8 @@ LL |     m!(0usize, 0..=usize::MAX);
    = help: add `#![feature(precise_pointer_size_matching)]` to the crate attributes to enable precise `usize` matching
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL ~         match $s { $($t)+ => {}
-LL ~         _ => todo!() }
-   |
+LL |         match $s { $($t)+ => {}, _ => todo!() }
+   |                                ++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `_` not covered
   --> $DIR/pointer-sized-int.rs:24:8
@@ -54,9 +53,8 @@ LL |     m!(0usize, 0..5 | 5..=usize::MAX);
    = help: add `#![feature(precise_pointer_size_matching)]` to the crate attributes to enable precise `usize` matching
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL ~         match $s { $($t)+ => {}
-LL ~         _ => todo!() }
-   |
+LL |         match $s { $($t)+ => {}, _ => todo!() }
+   |                                ++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `_` not covered
   --> $DIR/pointer-sized-int.rs:26:8
@@ -69,9 +67,8 @@ LL |     m!(0usize, 0..usize::MAX | usize::MAX);
    = help: add `#![feature(precise_pointer_size_matching)]` to the crate attributes to enable precise `usize` matching
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL ~         match $s { $($t)+ => {}
-LL ~         _ => todo!() }
-   |
+LL |         match $s { $($t)+ => {}, _ => todo!() }
+   |                                ++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `(_, _)` not covered
   --> $DIR/pointer-sized-int.rs:28:8
@@ -82,9 +79,8 @@ LL |     m!((0usize, true), (0..5, true) | (5..=usize::MAX, true) | (0..=usize::
    = note: the matched value is of type `(usize, bool)`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL ~         match $s { $($t)+ => {}
-LL ~         (_, _) => todo!() }
-   |
+LL |         match $s { $($t)+ => {}, (_, _) => todo!() }
+   |                                +++++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `_` not covered
   --> $DIR/pointer-sized-int.rs:31:8
@@ -97,9 +93,8 @@ LL |     m!(0isize, isize::MIN..=isize::MAX);
    = help: add `#![feature(precise_pointer_size_matching)]` to the crate attributes to enable precise `isize` matching
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL ~         match $s { $($t)+ => {}
-LL ~         _ => todo!() }
-   |
+LL |         match $s { $($t)+ => {}, _ => todo!() }
+   |                                ++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `_` not covered
   --> $DIR/pointer-sized-int.rs:33:8
@@ -112,9 +107,8 @@ LL |     m!(0isize, isize::MIN..5 | 5..=isize::MAX);
    = help: add `#![feature(precise_pointer_size_matching)]` to the crate attributes to enable precise `isize` matching
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL ~         match $s { $($t)+ => {}
-LL ~         _ => todo!() }
-   |
+LL |         match $s { $($t)+ => {}, _ => todo!() }
+   |                                ++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `_` not covered
   --> $DIR/pointer-sized-int.rs:35:8
@@ -127,9 +121,8 @@ LL |     m!(0isize, isize::MIN..isize::MAX | isize::MAX);
    = help: add `#![feature(precise_pointer_size_matching)]` to the crate attributes to enable precise `isize` matching
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL ~         match $s { $($t)+ => {}
-LL ~         _ => todo!() }
-   |
+LL |         match $s { $($t)+ => {}, _ => todo!() }
+   |                                ++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `(_, _)` not covered
   --> $DIR/pointer-sized-int.rs:37:8
@@ -140,9 +133,8 @@ LL |     m!((0isize, true), (isize::MIN..5, true)
    = note: the matched value is of type `(isize, bool)`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL ~         match $s { $($t)+ => {}
-LL ~         (_, _) => todo!() }
-   |
+LL |         match $s { $($t)+ => {}, (_, _) => todo!() }
+   |                                +++++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `_` not covered
   --> $DIR/pointer-sized-int.rs:41:11

src/test/ui/pattern/usefulness/non-exhaustive-match.stderr

@@ -12,8 +12,8 @@ LL | enum T { A, B }
    = note: the matched value is of type `T`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL |     match x { T::B => { } A => todo!() }
-   |                           ++++++++++++
+LL |     match x { T::B => { }, A => todo!() }
+   |                          ++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `false` not covered
   --> $DIR/non-exhaustive-match.rs:8:11