Rollup merge of #58267 - estebank:match-arms, r=matthewjasper

Tweak "incompatible match arms" error

- Point at the body expression of the match arm with the type error.
- Point at the prior match arms explicitly stating the evaluated type.
- Point at the entire match expr in a secondary span, instead of primary.
- For type errors in the first match arm, the cause is outside of the
  match, treat as implicit block error to give a more appropriate error.

Fix #46776, fix #57206.
CC #24157, #38234.

6 files changed, 33 insertions, 24 deletions

diff --git a/src/test/ui/issues/issue-11319.rs b/src/test/ui/issues/issue-11319.rs
index ea901205544..726c437355e 100644
--- a/src/test/ui/issues/issue-11319.rs
+++ b/src/test/ui/issues/issue-11319.rs
@@ -1,12 +1,14 @@
 fn main() {
     match Some(10) {
-    //~^ ERROR match arms have incompatible types
-    //~| expected type `bool`
-    //~| found type `()`
-    //~| expected bool, found ()
+    //~^ NOTE `match` arms have incompatible types
         Some(5) => false,
+        //~^ NOTE this is found to be of type `bool`
         Some(2) => true,
+        //~^ NOTE this is found to be of type `bool`
         None    => (),
+        //~^ ERROR match arms have incompatible types
+        //~| NOTE expected bool, found ()
+        //~| NOTE expected type `bool`
         _       => true
     }
 }
diff --git a/src/test/ui/issues/issue-11319.stderr b/src/test/ui/issues/issue-11319.stderr
index 44d63ba3e68..10db477b8ca 100644
--- a/src/test/ui/issues/issue-11319.stderr
+++ b/src/test/ui/issues/issue-11319.stderr
@@ -1,16 +1,20 @@
 error[E0308]: match arms have incompatible types
-  --> $DIR/issue-11319.rs:2:5
+  --> $DIR/issue-11319.rs:8:20
    |
 LL | /     match Some(10) {
-LL | |     //~^ ERROR match arms have incompatible types
-LL | |     //~| expected type `bool`
-LL | |     //~| found type `()`
-...  |
+LL | |     //~^ NOTE `match` arms have incompatible types
+LL | |         Some(5) => false,
+   | |                    ----- this is found to be of type `bool`
+LL | |         //~^ NOTE this is found to be of type `bool`
+LL | |         Some(2) => true,
+   | |                    ---- this is found to be of type `bool`
+LL | |         //~^ NOTE this is found to be of type `bool`
 LL | |         None    => (),
-   | |                    -- match arm with an incompatible type
+   | |                    ^^ expected bool, found ()
+...  |
 LL | |         _       => true
 LL | |     }
-   | |_____^ expected bool, found ()
+   | |_____- `match` arms have incompatible types
    |
    = note: expected type `bool`
               found type `()`
diff --git a/src/test/ui/issues/issue-17728.rs b/src/test/ui/issues/issue-17728.rs
index 0f13ae3304d..15cea1d609d 100644
--- a/src/test/ui/issues/issue-17728.rs
+++ b/src/test/ui/issues/issue-17728.rs
@@ -97,7 +97,7 @@ impl Debug for Player {
 }
 
 fn str_to_direction(to_parse: &str) -> RoomDirection {
-    match to_parse { //~ ERROR match arms have incompatible types
+    match to_parse {
         "w" | "west" => RoomDirection::West,
         "e" | "east" => RoomDirection::East,
         "n" | "north" => RoomDirection::North,
@@ -108,6 +108,7 @@ fn str_to_direction(to_parse: &str) -> RoomDirection {
         "down" => RoomDirection::Down,
         _ => None
     }
+        //~^^ ERROR match arms have incompatible types
 }
 
 fn main() {
diff --git a/src/test/ui/issues/issue-17728.stderr b/src/test/ui/issues/issue-17728.stderr
index 355868f0569..2c2efad19f5 100644
--- a/src/test/ui/issues/issue-17728.stderr
+++ b/src/test/ui/issues/issue-17728.stderr
@@ -10,17 +10,19 @@ LL |             Some(entry) => Ok(entry),
    |                            ^^^^^^^^^ ...but data from `room` is returned here
 
 error[E0308]: match arms have incompatible types
-  --> $DIR/issue-17728.rs:100:5
+  --> $DIR/issue-17728.rs:109:14
    |
-LL | /     match to_parse { //~ ERROR match arms have incompatible types
+LL | /     match to_parse {
 LL | |         "w" | "west" => RoomDirection::West,
 LL | |         "e" | "east" => RoomDirection::East,
 LL | |         "n" | "north" => RoomDirection::North,
 ...  |
+LL | |         "down" => RoomDirection::Down,
+   | |                   ------------------- this and all prior arms are found to be of type `RoomDirection`
 LL | |         _ => None
-   | |              ---- match arm with an incompatible type
+   | |              ^^^^ expected enum `RoomDirection`, found enum `std::option::Option`
 LL | |     }
-   | |_____^ expected enum `RoomDirection`, found enum `std::option::Option`
+   | |_____- `match` arms have incompatible types
    |
    = note: expected type `RoomDirection`
               found type `std::option::Option<_>`
diff --git a/src/test/ui/issues/issue-24036.rs b/src/test/ui/issues/issue-24036.rs
index 3642085934a..2f501b941b5 100644
--- a/src/test/ui/issues/issue-24036.rs
+++ b/src/test/ui/issues/issue-24036.rs
@@ -6,11 +6,11 @@ fn closure_to_loc() {
 
 fn closure_from_match() {
     let x = match 1usize {
-    //~^ ERROR match arms have incompatible types
         1 => |c| c + 1,
         2 => |c| c - 1,
         _ => |c| c - 1
     };
+    //~^^^ ERROR match arms have incompatible types
 }
 
 fn main() { }
diff --git a/src/test/ui/issues/issue-24036.stderr b/src/test/ui/issues/issue-24036.stderr
index 9f799c9b450..fa9935fcf61 100644
--- a/src/test/ui/issues/issue-24036.stderr
+++ b/src/test/ui/issues/issue-24036.stderr
@@ -10,20 +10,20 @@ LL |     x = |c| c + 1;
    = help: consider boxing your closure and/or using it as a trait object
 
 error[E0308]: match arms have incompatible types
-  --> $DIR/issue-24036.rs:8:13
+  --> $DIR/issue-24036.rs:10:14
    |
 LL |       let x = match 1usize {
-   |  _____________^
-LL | |     //~^ ERROR match arms have incompatible types
+   |  _____________-
 LL | |         1 => |c| c + 1,
+   | |              --------- this is found to be of type `[closure@$DIR/issue-24036.rs:9:14: 9:23]`
 LL | |         2 => |c| c - 1,
-   | |              --------- match arm with an incompatible type
+   | |              ^^^^^^^^^ expected closure, found a different closure
 LL | |         _ => |c| c - 1
 LL | |     };
-   | |_____^ expected closure, found a different closure
+   | |_____- `match` arms have incompatible types
    |
-   = note: expected type `[closure@$DIR/issue-24036.rs:10:14: 10:23]`
-              found type `[closure@$DIR/issue-24036.rs:11:14: 11:23]`
+   = note: expected type `[closure@$DIR/issue-24036.rs:9:14: 9:23]`
+              found type `[closure@$DIR/issue-24036.rs:10:14: 10:23]`
    = note: no two closures, even if identical, have the same type
    = help: consider boxing your closure and/or using it as a trait object