Merge #1680

1680: Correctly infer match with early return r=flodiebold a=SomeoneToIgnore

Fixes #1505

Co-authored-by: Kirill Bulatov <[email protected]>
Co-authored-by: Florian Diebold <[email protected]>

1 files changed, 130 insertions, 10 deletions

diff --git a/crates/ra_hir/src/ty/tests.rs b/crates/ra_hir/src/ty/tests.rs
index c5818b738..e3eb0c3fa 100644
--- a/crates/ra_hir/src/ty/tests.rs
+++ b/crates/ra_hir/src/ty/tests.rs
@@ -718,16 +718,18 @@ fn main(foo: Foo) {
 }
 "#),
         @r###"
-[35; 38) 'foo': Foo
-[45; 109) '{     ...   } }': ()
-[51; 107) 'if tru...     }': ()
-[54; 58) 'true': bool
-[59; 67) '{      }': ()
-[73; 107) 'if fal...     }': i32
-[76; 81) 'false': bool
-[82; 107) '{     ...     }': i32
-[92; 95) 'foo': Foo
-[92; 101) 'foo.field': i32"###
+   ⋮
+   ⋮[35; 38) 'foo': Foo
+   ⋮[45; 109) '{     ...   } }': ()
+   ⋮[51; 107) 'if tru...     }': ()
+   ⋮[54; 58) 'true': bool
+   ⋮[59; 67) '{      }': ()
+   ⋮[73; 107) 'if fal...     }': ()
+   ⋮[76; 81) 'false': bool
+   ⋮[82; 107) '{     ...     }': i32
+   ⋮[92; 95) 'foo': Foo
+   ⋮[92; 101) 'foo.field': i32
+    "###
     )
 }
 
@@ -3594,3 +3596,121 @@ fn no_such_field_diagnostics() {
 "###
     );
 }
+
+mod branching_with_never_tests {
+    use super::type_at;
+
+    #[test]
+    fn if_never() {
+        let t = type_at(
+            r#"
+//- /main.rs
+fn test() {
+    let i = if true {
+        loop {}
+    } else {
+        3.0
+    };
+    i<|>
+    ()
+}
+"#,
+        );
+        assert_eq!(t, "f64");
+    }
+
+    #[test]
+    fn if_else_never() {
+        let t = type_at(
+            r#"
+//- /main.rs
+fn test(input: bool) {
+    let i = if input {
+        2.0
+    } else {
+        return
+    };
+    i<|>
+    ()
+}
+"#,
+        );
+        assert_eq!(t, "f64");
+    }
+
+    #[test]
+    fn match_first_arm_never() {
+        let t = type_at(
+            r#"
+//- /main.rs
+fn test(a: i32) {
+    let i = match a {
+        1 => return,
+        2 => 2.0,
+        3 => loop {},
+        _ => 3.0,
+    };
+    i<|>
+    ()
+}
+"#,
+        );
+        assert_eq!(t, "f64");
+    }
+
+    #[test]
+    fn match_second_arm_never() {
+        let t = type_at(
+            r#"
+//- /main.rs
+fn test(a: i32) {
+    let i = match a {
+        1 => 3.0,
+        2 => loop {},
+        3 => 3.0,
+        _ => return,
+    };
+    i<|>
+    ()
+}
+"#,
+        );
+        assert_eq!(t, "f64");
+    }
+
+    #[test]
+    fn match_all_arms_never() {
+        let t = type_at(
+            r#"
+//- /main.rs
+fn test(a: i32) {
+    let i = match a {
+        2 => return,
+        _ => loop {},
+    };
+    i<|>
+    ()
+}
+"#,
+        );
+        assert_eq!(t, "!");
+    }
+
+    #[test]
+    fn match_no_never_arms() {
+        let t = type_at(
+            r#"
+//- /main.rs
+fn test(a: i32) {
+    let i = match a {
+        2 => 2.0,
+        _ => 3.0,
+    };
+    i<|>
+    ()
+}
+"#,
+        );
+        assert_eq!(t, "f64");
+    }
+}