1 files changed, 176 insertions, 1 deletions

diff --git a/crates/ra_hir_ty/src/tests/never_type.rs b/crates/ra_hir_ty/src/tests/never_type.rs
index a77209480..082c47208 100644
--- a/crates/ra_hir_ty/src/tests/never_type.rs
+++ b/crates/ra_hir_ty/src/tests/never_type.rs
@@ -1,4 +1,6 @@
-use super::type_at;
+use insta::assert_snapshot;
+
+use super::{infer_with_mismatches, type_at};
 
 #[test]
 fn infer_never1() {
@@ -261,3 +263,176 @@ fn test(a: i32) {
     );
     assert_eq!(t, "f64");
 }
+
+#[test]
+fn diverging_expression_1() {
+    let t = infer_with_mismatches(
+        r#"
+//- /main.rs
+fn test1() {
+    let x: u32 = return;
+}
+fn test2() {
+    let x: u32 = { return; };
+}
+fn test3() {
+    let x: u32 = loop {};
+}
+fn test4() {
+    let x: u32 = { loop {} };
+}
+fn test5() {
+    let x: u32 = { if true { loop {}; } else { loop {}; } };
+}
+fn test6() {
+    let x: u32 = { let y: u32 = { loop {}; }; };
+}
+"#,
+        true,
+    );
+    assert_snapshot!(t, @r###"
+    25..53 '{     ...urn; }': ()
+    35..36 'x': u32
+    44..50 'return': !
+    65..98 '{     ...; }; }': ()
+    75..76 'x': u32
+    84..95 '{ return; }': u32
+    86..92 'return': !
+    110..139 '{     ... {}; }': ()
+    120..121 'x': u32
+    129..136 'loop {}': !
+    134..136 '{}': ()
+    151..184 '{     ...} }; }': ()
+    161..162 'x': u32
+    170..181 '{ loop {} }': u32
+    172..179 'loop {}': !
+    177..179 '{}': ()
+    196..260 '{     ...} }; }': ()
+    206..207 'x': u32
+    215..257 '{ if t...}; } }': u32
+    217..255 'if tru... {}; }': u32
+    220..224 'true': bool
+    225..237 '{ loop {}; }': u32
+    227..234 'loop {}': !
+    232..234 '{}': ()
+    243..255 '{ loop {}; }': u32
+    245..252 'loop {}': !
+    250..252 '{}': ()
+    272..324 '{     ...; }; }': ()
+    282..283 'x': u32
+    291..321 '{ let ...; }; }': u32
+    297..298 'y': u32
+    306..318 '{ loop {}; }': u32
+    308..315 'loop {}': !
+    313..315 '{}': ()
+    "###);
+}
+
+#[test]
+fn diverging_expression_2() {
+    let t = infer_with_mismatches(
+        r#"
+//- /main.rs
+fn test1() {
+    // should give type mismatch
+    let x: u32 = { loop {}; "foo" };
+}
+"#,
+        true,
+    );
+    assert_snapshot!(t, @r###"
+    25..98 '{     ..." }; }': ()
+    68..69 'x': u32
+    77..95 '{ loop...foo" }': &str
+    79..86 'loop {}': !
+    84..86 '{}': ()
+    88..93 '"foo"': &str
+    77..95: expected u32, got &str
+    88..93: expected u32, got &str
+    "###);
+}
+
+#[test]
+fn diverging_expression_3_break() {
+    let t = infer_with_mismatches(
+        r#"
+//- /main.rs
+fn test1() {
+    // should give type mismatch
+    let x: u32 = { loop { break; } };
+}
+fn test2() {
+    // should give type mismatch
+    let x: u32 = { for a in b { break; }; };
+    // should give type mismatch as well
+    let x: u32 = { for a in b {}; };
+    // should give type mismatch as well
+    let x: u32 = { for a in b { return; }; };
+}
+fn test3() {
+    // should give type mismatch
+    let x: u32 = { while true { break; }; };
+    // should give type mismatch as well -- there's an implicit break, even if it's never hit
+    let x: u32 = { while true {}; };
+    // should give type mismatch as well
+    let x: u32 = { while true { return; }; };
+}
+"#,
+        true,
+    );
+    assert_snapshot!(t, @r###"
+    25..99 '{     ...} }; }': ()
+    68..69 'x': u32
+    77..96 '{ loop...k; } }': ()
+    79..94 'loop { break; }': ()
+    84..94 '{ break; }': ()
+    86..91 'break': !
+    77..96: expected u32, got ()
+    79..94: expected u32, got ()
+    111..357 '{     ...; }; }': ()
+    154..155 'x': u32
+    163..189 '{ for ...; }; }': ()
+    165..186 'for a ...eak; }': ()
+    169..170 'a': {unknown}
+    174..175 'b': {unknown}
+    176..186 '{ break; }': ()
+    178..183 'break': !
+    240..241 'x': u32
+    249..267 '{ for ... {}; }': ()
+    251..264 'for a in b {}': ()
+    255..256 'a': {unknown}
+    260..261 'b': {unknown}
+    262..264 '{}': ()
+    318..319 'x': u32
+    327..354 '{ for ...; }; }': ()
+    329..351 'for a ...urn; }': ()
+    333..334 'a': {unknown}
+    338..339 'b': {unknown}
+    340..351 '{ return; }': ()
+    342..348 'return': !
+    163..189: expected u32, got ()
+    249..267: expected u32, got ()
+    327..354: expected u32, got ()
+    369..668 '{     ...; }; }': ()
+    412..413 'x': u32
+    421..447 '{ whil...; }; }': ()
+    423..444 'while ...eak; }': ()
+    429..433 'true': bool
+    434..444 '{ break; }': ()
+    436..441 'break': !
+    551..552 'x': u32
+    560..578 '{ whil... {}; }': ()
+    562..575 'while true {}': ()
+    568..572 'true': bool
+    573..575 '{}': ()
+    629..630 'x': u32
+    638..665 '{ whil...; }; }': ()
+    640..662 'while ...urn; }': ()
+    646..650 'true': bool
+    651..662 '{ return; }': ()
+    653..659 'return': !
+    421..447: expected u32, got ()
+    560..578: expected u32, got ()
+    638..665: expected u32, got ()
+    "###);
+}