check_pat_path: use pattern_cause

src/librustc_typeck/check/pat.rs

@@ -155,7 +155,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 self.check_pat_tuple_struct(pat, qpath, subpats, ddpos, expected, def_bm, ti)
             }
             PatKind::Path(ref qpath) => {
-                self.check_pat_path(pat, path_res.unwrap(), qpath, expected)
+                self.check_pat_path(pat, path_res.unwrap(), qpath, expected, ti)
             }
             PatKind::Struct(ref qpath, fields, etc) => {
                 self.check_pat_struct(pat, qpath, fields, etc, expected, def_bm, ti)
@@ -671,6 +671,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         path_resolution: (Res, Option<Ty<'tcx>>, &'b [hir::PathSegment<'b>]),
         qpath: &hir::QPath<'_>,
         expected: Ty<'tcx>,
+        ti: TopInfo<'tcx>,
     ) -> Ty<'tcx> {
         let tcx = self.tcx;
 
@@ -696,7 +697,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         // Type-check the path.
         let pat_ty = self.instantiate_value_path(segments, opt_ty, res, pat.span, pat.hir_id).0;
-        self.demand_suptype(pat.span, expected, pat_ty);
+        if let Some(mut err) =
+            self.demand_suptype_with_origin(&self.pattern_cause(ti, pat.span), expected, pat_ty)
+        {
+            err.emit();
+        }
         pat_ty
     }
 

src/test/ui/issues/issue-12552.stderr

@@ -12,6 +12,9 @@ LL |     Some(k) => match k {
 error[E0308]: mismatched types
   --> $DIR/issue-12552.rs:9:5
    |
+LL |   match t {
+   |         - this expression has type `std::result::Result<_, {integer}>`
+...
 LL |     None => ()
    |     ^^^^ expected enum `std::result::Result`, found enum `std::option::Option`
    |

src/test/ui/issues/issue-37026.stderr

@@ -2,7 +2,9 @@ error[E0308]: mismatched types
   --> $DIR/issue-37026.rs:6:9
    |
 LL |     let empty_struct::XEmpty2 = ();
-   |         ^^^^^^^^^^^^^^^^^^^^^ expected `()`, found struct `empty_struct::XEmpty2`
+   |         ^^^^^^^^^^^^^^^^^^^^^   -- this expression has type `()`
+   |         |
+   |         expected `()`, found struct `empty_struct::XEmpty2`
 
 error[E0308]: mismatched types
   --> $DIR/issue-37026.rs:7:9

src/test/ui/issues/issue-5100.stderr

@@ -1,6 +1,8 @@
 error[E0308]: mismatched types
   --> $DIR/issue-5100.rs:8:9
    |
+LL |     match (true, false) {
+   |           ------------- this expression has type `(bool, bool)`
 LL |         A::B => (),
    |         ^^^^ expected tuple, found enum `A`
    |

src/test/ui/issues/issue-7867.stderr

@@ -1,6 +1,8 @@
 error[E0308]: mismatched types
   --> $DIR/issue-7867.rs:7:9
    |
+LL |     match (true, false) {
+   |           ------------- this expression has type `(bool, bool)`
 LL |         A::B => (),
    |         ^^^^ expected tuple, found enum `A`
    |

src/test/ui/match/match-tag-nullary.stderr

@@ -2,7 +2,9 @@ error[E0308]: mismatched types
   --> $DIR/match-tag-nullary.rs:4:40
    |
 LL | fn main() { let x: A = A::A; match x { B::B => { } } }
-   |                                        ^^^^ expected enum `A`, found enum `B`
+   |                                    -   ^^^^ expected enum `A`, found enum `B`
+   |                                    |
+   |                                    this expression has type `A`
 
 error: aborting due to previous error
 

src/test/ui/pattern/pattern-ident-path-generics.stderr

@@ -1,6 +1,8 @@
 error[E0308]: mismatched types
   --> $DIR/pattern-ident-path-generics.rs:3:9
    |
+LL |     match Some("foo") {
+   |           ----------- this expression has type `std::option::Option<&str>`
 LL |         None::<isize> => {}
    |         ^^^^^^^^^^^^^ expected `&str`, found `isize`
    |

src/test/ui/resolve/name-clash-nullary.stderr

@@ -2,7 +2,9 @@ error[E0308]: mismatched types
   --> $DIR/name-clash-nullary.rs:2:7
    |
 LL |   let None: isize = 42;
-   |       ^^^^ expected `isize`, found enum `std::option::Option`
+   |       ^^^^  ----- expected due to this
+   |       |
+   |       expected `isize`, found enum `std::option::Option`
    |
    = note: expected type `isize`
               found enum `std::option::Option<_>`

src/test/ui/rfc-2005-default-binding-mode/const.stderr

@@ -1,6 +1,8 @@
 error[E0308]: mismatched types
   --> $DIR/const.rs:14:9
    |
+LL |     match &f {
+   |           -- this expression has type `&Foo`
 LL |         FOO => {},
    |         ^^^ expected `&Foo`, found struct `Foo`