Point at the match discriminant when arm pattern has a type mismatch

20 files changed, 54 insertions, 2 deletions

diff --git a/src/test/ui/block-result/issue-13624.stderr b/src/test/ui/block-result/issue-13624.stderr
index b38633b0ffe..545d4916cf7 100644
--- a/src/test/ui/block-result/issue-13624.stderr
+++ b/src/test/ui/block-result/issue-13624.stderr
@@ -12,6 +12,8 @@ LL |     Enum::EnumStructVariant { x: 1, y: 2, z: 3 }
 error[E0308]: mismatched types
   --> $DIR/issue-13624.rs:22:9
    |
+LL |       match enum_struct_variant {
+   |             ------------------- this match expression evaluates to `()`
 LL |         a::Enum::EnumStructVariant { x, y, z } => {
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected (), found enum `a::Enum`
    |
diff --git a/src/test/ui/error-codes/E0308-4.stderr b/src/test/ui/error-codes/E0308-4.stderr
index 8117bc754b6..7971f1d9eda 100644
--- a/src/test/ui/error-codes/E0308-4.stderr
+++ b/src/test/ui/error-codes/E0308-4.stderr
@@ -1,6 +1,8 @@
 error[E0308]: mismatched types
   --> $DIR/E0308-4.rs:4:9
    |
+LL |     match x {
+   |           - this match expression evaluates to `u8`
 LL |         0u8..=3i8 => (), //~ ERROR E0308
    |         ^^^^^^^^^ expected u8, found i8
 
diff --git a/src/test/ui/issues/issue-11844.stderr b/src/test/ui/issues/issue-11844.stderr
index 05d2685958e..4459b64aa8f 100644
--- a/src/test/ui/issues/issue-11844.stderr
+++ b/src/test/ui/issues/issue-11844.stderr
@@ -1,6 +1,8 @@
 error[E0308]: mismatched types
   --> $DIR/issue-11844.rs:6:9
    |
+LL |     match a {
+   |           - this match expression evaluates to `std::option::Option<std::boxed::Box<{integer}>>`
 LL |         Ok(a) => //~ ERROR: mismatched types
    |         ^^^^^ expected enum `std::option::Option`, found enum `std::result::Result`
    |
diff --git a/src/test/ui/issues/issue-12552.stderr b/src/test/ui/issues/issue-12552.stderr
index ca5efcdc472..b299b3fb3e8 100644
--- a/src/test/ui/issues/issue-12552.stderr
+++ b/src/test/ui/issues/issue-12552.stderr
@@ -1,6 +1,8 @@
 error[E0308]: mismatched types
   --> $DIR/issue-12552.rs:6:5
    |
+LL |   match t {
+   |         - this match expression evaluates to `std::result::Result<_, {integer}>`
 LL |     Some(k) => match k { //~ ERROR mismatched types
    |     ^^^^^^^ expected enum `std::result::Result`, found enum `std::option::Option`
    |
diff --git a/src/test/ui/issues/issue-13466.stderr b/src/test/ui/issues/issue-13466.stderr
index 2f60070337b..8ba5114d143 100644
--- a/src/test/ui/issues/issue-13466.stderr
+++ b/src/test/ui/issues/issue-13466.stderr
@@ -1,6 +1,8 @@
 error[E0308]: mismatched types
   --> $DIR/issue-13466.rs:8:9
    |
+LL |     let _x: usize = match Some(1) {
+   |                           ------- this match expression evaluates to `std::option::Option<{integer}>`
 LL |         Ok(u) => u,
    |         ^^^^^ expected enum `std::option::Option`, found enum `std::result::Result`
    |
@@ -10,6 +12,9 @@ LL |         Ok(u) => u,
 error[E0308]: mismatched types
   --> $DIR/issue-13466.rs:14:9
    |
+LL |     let _x: usize = match Some(1) {
+   |                           ------- this match expression evaluates to `std::option::Option<{integer}>`
+...
 LL |         Err(e) => panic!(e)
    |         ^^^^^^ expected enum `std::option::Option`, found enum `std::result::Result`
    |
diff --git a/src/test/ui/issues/issue-15896.stderr b/src/test/ui/issues/issue-15896.stderr
index cd629841fee..b88bfea7e85 100644
--- a/src/test/ui/issues/issue-15896.stderr
+++ b/src/test/ui/issues/issue-15896.stderr
@@ -1,6 +1,9 @@
 error[E0308]: mismatched types
   --> $DIR/issue-15896.rs:11:11
    |
+LL |     let u = match e {
+   |                   - this match expression evaluates to `main::R`
+LL |         E::B(
 LL |           Tau{t: x},
    |           ^^^^^^^^^ expected enum `main::R`, found struct `main::Tau`
    |
diff --git a/src/test/ui/issues/issue-16401.stderr b/src/test/ui/issues/issue-16401.stderr
index a1cf6c98705..ea5f89d18dd 100644
--- a/src/test/ui/issues/issue-16401.stderr
+++ b/src/test/ui/issues/issue-16401.stderr
@@ -1,6 +1,8 @@
 error[E0308]: mismatched types
   --> $DIR/issue-16401.rs:8:9
    |
+LL |     match () {
+   |           -- this match expression evaluates to `()`
 LL |         Slice { data: data, len: len } => (),
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected (), found struct `Slice`
    |
diff --git a/src/test/ui/issues/issue-3680.stderr b/src/test/ui/issues/issue-3680.stderr
index 78c3f92fb53..82b6462d3b4 100644
--- a/src/test/ui/issues/issue-3680.stderr
+++ b/src/test/ui/issues/issue-3680.stderr
@@ -1,6 +1,8 @@
 error[E0308]: mismatched types
   --> $DIR/issue-3680.rs:3:9
    |
+LL |     match None {
+   |           ---- this match expression evaluates to `std::option::Option<_>`
 LL |         Err(_) => ()
    |         ^^^^^^ expected enum `std::option::Option`, found enum `std::result::Result`
    |
diff --git a/src/test/ui/issues/issue-5100.stderr b/src/test/ui/issues/issue-5100.stderr
index a6f6229fe78..d3072143c15 100644
--- a/src/test/ui/issues/issue-5100.stderr
+++ b/src/test/ui/issues/issue-5100.stderr
@@ -28,6 +28,8 @@ LL |         (true, false, false) => ()
 error[E0308]: mismatched types
   --> $DIR/issue-5100.rs:33:9
    |
+LL |     match (true, false) {
+   |           ------------- this match expression evaluates to `(bool, bool)`
 LL |         box (true, false) => ()
    |         ^^^^^^^^^^^^^^^^^ expected tuple, found struct `std::boxed::Box`
    |
diff --git a/src/test/ui/issues/issue-5358-1.stderr b/src/test/ui/issues/issue-5358-1.stderr
index dbbafb38e65..bdd70ebac94 100644
--- a/src/test/ui/issues/issue-5358-1.stderr
+++ b/src/test/ui/issues/issue-5358-1.stderr
@@ -1,6 +1,8 @@
 error[E0308]: mismatched types
   --> $DIR/issue-5358-1.rs:6:9
    |
+LL |     match S(Either::Left(5)) {
+   |           ------------------ this match expression evaluates to `S`
 LL |         Either::Right(_) => {}
    |         ^^^^^^^^^^^^^^^^ expected struct `S`, found enum `Either`
    |
diff --git a/src/test/ui/issues/issue-7092.stderr b/src/test/ui/issues/issue-7092.stderr
index aa24182e3a3..61564f9004e 100644
--- a/src/test/ui/issues/issue-7092.stderr
+++ b/src/test/ui/issues/issue-7092.stderr
@@ -1,6 +1,8 @@
 error[E0308]: mismatched types
   --> $DIR/issue-7092.rs:6:9
    |
+LL |     match x {
+   |           - this match expression evaluates to `Whatever`
 LL |         Some(field) =>
    |         ^^^^^^^^^^^ expected enum `Whatever`, found enum `std::option::Option`
    |
diff --git a/src/test/ui/match/match-range-fail.stderr b/src/test/ui/match/match-range-fail.stderr
index 54969927433..db7afc36bd7 100644
--- a/src/test/ui/match/match-range-fail.stderr
+++ b/src/test/ui/match/match-range-fail.stderr
@@ -19,6 +19,8 @@ LL |         10 ..= "what" => ()
 error[E0308]: mismatched types
   --> $DIR/match-range-fail.rs:17:9
    |
+LL |     match 5 {
+   |           - this match expression evaluates to `{integer}`
 LL |         'c' ..= 100 => { }
    |         ^^^^^^^^^^^ expected integer, found char
    |
diff --git a/src/test/ui/match/match-struct.stderr b/src/test/ui/match/match-struct.stderr
index bad41485a53..8e9d09288b1 100644
--- a/src/test/ui/match/match-struct.stderr
+++ b/src/test/ui/match/match-struct.stderr
@@ -1,6 +1,8 @@
 error[E0308]: mismatched types
   --> $DIR/match-struct.rs:6:9
    |
+LL |     match (S { a: 1 }) {
+   |           ------------ this match expression evaluates to `S`
 LL |         E::C(_) => (),
    |         ^^^^^^^ expected struct `S`, found enum `E`
    |
diff --git a/src/test/ui/match/match-tag-unary.stderr b/src/test/ui/match/match-tag-unary.stderr
index c90029b2fa1..f5e7051a9e8 100644
--- a/src/test/ui/match/match-tag-unary.stderr
+++ b/src/test/ui/match/match-tag-unary.stderr
@@ -2,7 +2,9 @@ error[E0308]: mismatched types
   --> $DIR/match-tag-unary.rs:4:43
    |
 LL | fn main() { let x: A = A::A(0); match x { B::B(y) => { } } } //~ ERROR mismatched types
-   |                                           ^^^^^^^ expected enum `A`, found enum `B`
+   |                                       -   ^^^^^^^ expected enum `A`, found enum `B`
+   |                                       |
+   |                                       this match expression evaluates to `A`
    |
    = note: expected type `A`
               found type `B`
diff --git a/src/test/ui/mismatched_types/E0409.stderr b/src/test/ui/mismatched_types/E0409.stderr
index 08f132efd05..4df2984a6dc 100644
--- a/src/test/ui/mismatched_types/E0409.stderr
+++ b/src/test/ui/mismatched_types/E0409.stderr
@@ -9,6 +9,8 @@ LL |         (0, ref y) | (y, 0) => {} //~ ERROR E0409
 error[E0308]: mismatched types
   --> $DIR/E0409.rs:5:23
    |
+LL |     match x {
+   |           - this match expression evaluates to `_`
 LL |         (0, ref y) | (y, 0) => {} //~ ERROR E0409
    |                       ^ expected &{integer}, found integer
    |
diff --git a/src/test/ui/or-pattern-mismatch.stderr b/src/test/ui/or-pattern-mismatch.stderr
index 731b2090a7b..49f68c7f068 100644
--- a/src/test/ui/or-pattern-mismatch.stderr
+++ b/src/test/ui/or-pattern-mismatch.stderr
@@ -2,7 +2,9 @@ error[E0308]: mismatched types
   --> $DIR/or-pattern-mismatch.rs:3:68
    |
 LL | fn main() { match Blah::A(1, 1, 2) { Blah::A(_, x, y) | Blah::B(x, y) => { } } }
-   |                                                                    ^ expected usize, found isize
+   |                   ----------------                                 ^ expected usize, found isize
+   |                   |
+   |                   this match expression evaluates to `_`
    |
    = note: expected type `usize`
               found type `isize`
diff --git a/src/test/ui/pattern/pattern-error-continue.stderr b/src/test/ui/pattern/pattern-error-continue.stderr
index c17d4b70f0b..318067cbb50 100644
--- a/src/test/ui/pattern/pattern-error-continue.stderr
+++ b/src/test/ui/pattern/pattern-error-continue.stderr
@@ -21,6 +21,8 @@ LL |         A::B(_, _, _) => (), //~ ERROR this pattern has 3 fields, but
 error[E0308]: mismatched types
   --> $DIR/pattern-error-continue.rs:22:9
    |
+LL |     match 'c' {
+   |           --- this match expression evaluates to `char`
 LL |         S { .. } => (),
    |         ^^^^^^^^ expected char, found struct `S`
    |
diff --git a/src/test/ui/pattern/pattern-tyvar.stderr b/src/test/ui/pattern/pattern-tyvar.stderr
index dae17fa5166..cb9058a30da 100644
--- a/src/test/ui/pattern/pattern-tyvar.stderr
+++ b/src/test/ui/pattern/pattern-tyvar.stderr
@@ -1,6 +1,8 @@
 error[E0308]: mismatched types
   --> $DIR/pattern-tyvar.rs:5:18
    |
+LL |     match t {
+   |           - this match expression evaluates to `std::option::Option<std::vec::Vec<isize>>`
 LL |       Bar::T1(_, Some::<isize>(x)) => { //~ ERROR mismatched types
    |                  ^^^^^^^^^^^^^^^^ expected struct `std::vec::Vec`, found isize
    |
diff --git a/src/test/ui/resolve/resolve-inconsistent-binding-mode.stderr b/src/test/ui/resolve/resolve-inconsistent-binding-mode.stderr
index a14d3d67b10..69b151c733b 100644
--- a/src/test/ui/resolve/resolve-inconsistent-binding-mode.stderr
+++ b/src/test/ui/resolve/resolve-inconsistent-binding-mode.stderr
@@ -23,6 +23,8 @@ LL |       Opts::A(ref mut i) | Opts::B(ref i) => {}
 error[E0308]: mismatched types
   --> $DIR/resolve-inconsistent-binding-mode.rs:7:32
    |
+LL |     match x {
+   |           - this match expression evaluates to `_`
 LL |       Opts::A(ref i) | Opts::B(i) => {}
    |                                ^ expected &isize, found isize
    |
@@ -32,6 +34,8 @@ LL |       Opts::A(ref i) | Opts::B(i) => {}
 error[E0308]: mismatched types
   --> $DIR/resolve-inconsistent-binding-mode.rs:16:32
    |
+LL |     match x {
+   |           - this match expression evaluates to `_`
 LL |       Opts::A(ref i) | Opts::B(i) => {}
    |                                ^ expected &isize, found isize
    |
@@ -41,6 +45,8 @@ LL |       Opts::A(ref i) | Opts::B(i) => {}
 error[E0308]: mismatched types
   --> $DIR/resolve-inconsistent-binding-mode.rs:25:36
    |
+LL |     match x {
+   |           - this match expression evaluates to `_`
 LL |       Opts::A(ref mut i) | Opts::B(ref i) => {}
    |                                    ^^^^^ types differ in mutability
    |
diff --git a/src/test/ui/structs/structure-constructor-type-mismatch.stderr b/src/test/ui/structs/structure-constructor-type-mismatch.stderr
index 3c1ed8e69a6..564e3551065 100644
--- a/src/test/ui/structs/structure-constructor-type-mismatch.stderr
+++ b/src/test/ui/structs/structure-constructor-type-mismatch.stderr
@@ -109,6 +109,8 @@ LL |         PointF::<u32> { .. } => {} //~ ERROR wrong number of type arguments
 error[E0308]: mismatched types
   --> $DIR/structure-constructor-type-mismatch.rs:54:9
    |
+LL |     match (Point { x: 1, y: 2 }) {
+   |           ---------------------- this match expression evaluates to `Point<{integer}>`
 LL |         PointF::<u32> { .. } => {} //~ ERROR wrong number of type arguments
    |         ^^^^^^^^^^^^^^^^^^^^ expected integer, found f32
    |
@@ -118,6 +120,8 @@ LL |         PointF::<u32> { .. } => {} //~ ERROR wrong number of type arguments
 error[E0308]: mismatched types
   --> $DIR/structure-constructor-type-mismatch.rs:59:9
    |
+LL |     match (Point { x: 1, y: 2 }) {
+   |           ---------------------- this match expression evaluates to `Point<{integer}>`
 LL |         PointF { .. } => {} //~ ERROR mismatched types
    |         ^^^^^^^^^^^^^ expected integer, found f32
    |
@@ -127,6 +131,8 @@ LL |         PointF { .. } => {} //~ ERROR mismatched types
 error[E0308]: mismatched types
   --> $DIR/structure-constructor-type-mismatch.rs:67:9
    |
+LL |     match (Pair { x: 1, y: 2 }) {
+   |           --------------------- this match expression evaluates to `Pair<{integer}, {integer}>`
 LL |         PairF::<u32> { .. } => {} //~ ERROR mismatched types
    |         ^^^^^^^^^^^^^^^^^^^ expected integer, found f32
    |