Merge #5066

5066: Infer type for slice wildcard patterns r=flodiebold a=adamrk

Resolves https://github.com/rust-analyzer/rust-analyzer/issues/4830

The issue is just that we were never inferring the type for the wildcard `..` in slice patterns.

Co-authored-by: adamrk <[email protected]>

2 files changed, 27 insertions, 0 deletions

diff --git a/crates/ra_hir_ty/src/tests/patterns.rs b/crates/ra_hir_ty/src/tests/patterns.rs
index e5ef241ca..f937426bd 100644
--- a/crates/ra_hir_ty/src/tests/patterns.rs
+++ b/crates/ra_hir_ty/src/tests/patterns.rs
@@ -627,3 +627,28 @@ fn test() {
     "###
     );
 }
+
+#[test]
+fn slice_tail_pattern() {
+    assert_snapshot!(
+        infer(r#"
+fn foo(params: &[i32]) {
+    match params {
+        [head, tail @ ..] => {
+        }
+    }
+}
+"#),
+        @r###"
+    7..13 'params': &[i32]
+    23..92 '{     ...   } }': ()
+    29..90 'match ...     }': ()
+    35..41 'params': &[i32]
+    52..69 '[head,... @ ..]': [i32]
+    53..57 'head': &i32
+    59..68 'tail @ ..': &[i32]
+    66..68 '..': [i32]
+    73..84 '{         }': ()
+    "###
+    );
+}
diff --git a/crates/ra_hir_ty/src/tests/regression.rs b/crates/ra_hir_ty/src/tests/regression.rs
index eedaa27ba..aa37326df 100644
--- a/crates/ra_hir_ty/src/tests/regression.rs
+++ b/crates/ra_hir_ty/src/tests/regression.rs
@@ -500,6 +500,8 @@ fn foo(params: &[usize]) {
     31..78 'match ...     }': ()
     37..43 'params': &[usize]
     54..66 '[ps @ .., _]': [usize]
+    55..62 'ps @ ..': &[usize]
+    60..62 '..': [usize]
     64..65 '_': usize
     70..72 '{}': ()
     "###