Merge #701

701: Minor type inference tweaks r=flodiebold a=marcusklaas

Pass down expectation for reference expressions and type the guard in match expressions.

I wasn't able to add a test for the former addition because the type variable previously introduced would always resolve to the right type in the things I tried!

Co-authored-by: Marcus Klaas de Vries <[email protected]>

1 files changed, 16 insertions, 2 deletions

diff --git a/crates/ra_syntax/src/grammar/expressions/atom.rs b/crates/ra_syntax/src/grammar/expressions/atom.rs
index 6d6d89f70..600774afd 100644
--- a/crates/ra_syntax/src/grammar/expressions/atom.rs
+++ b/crates/ra_syntax/src/grammar/expressions/atom.rs
@@ -360,8 +360,8 @@ fn match_arm(p: &mut Parser) -> BlockLike {
     while p.eat(PIPE) {
         patterns::pattern(p);
     }
-    if p.eat(IF_KW) {
-        expr(p);
+    if p.at(IF_KW) {
+        match_guard(p);
     }
     p.expect(FAT_ARROW);
     let ret = expr_stmt(p);
@@ -369,6 +369,20 @@ fn match_arm(p: &mut Parser) -> BlockLike {
     ret
 }
 
+// test match_guard
+// fn foo() {
+//     match () {
+//         _ if foo => (),
+//     }
+// }
+fn match_guard(p: &mut Parser) -> CompletedMarker {
+    assert!(p.at(IF_KW));
+    let m = p.start();
+    p.bump();
+    expr(p);
+    m.complete(p, MATCH_GUARD)
+}
+
 // test block_expr
 // fn foo() {
 //     {};