Handle cycles in type vars

This might be the cause of #587.

3 files changed, 62 insertions, 0 deletions

diff --git a/crates/ra_hir/src/ty/snapshots/tests__recursive_vars.snap b/crates/ra_hir/src/ty/snapshots/tests__recursive_vars.snap
new file mode 100644
index 000000000..c3227ff7e
--- /dev/null
+++ b/crates/ra_hir/src/ty/snapshots/tests__recursive_vars.snap
@@ -0,0 +1,14 @@
+---
+created: "2019-01-26T22:42:22.329980185+00:00"
+creator: [email protected]
+expression: "&result"
+source: crates/ra_hir/src/ty/tests.rs
+---
+[11; 48) '{     ...&y]; }': ()
+[21; 22) 'y': &[unknown]
+[25; 32) 'unknown': &[unknown]
+[38; 45) '[y, &y]': [&&[unknown]]
+[39; 40) 'y': &[unknown]
+[42; 44) '&y': &&[unknown]
+[43; 44) 'y': &[unknown]
+
diff --git a/crates/ra_hir/src/ty/snapshots/tests__recursive_vars_2.snap b/crates/ra_hir/src/ty/snapshots/tests__recursive_vars_2.snap
new file mode 100644
index 000000000..de124da5b
--- /dev/null
+++ b/crates/ra_hir/src/ty/snapshots/tests__recursive_vars_2.snap
@@ -0,0 +1,21 @@
+---
+created: "2019-01-26T22:42:22.331805845+00:00"
+creator: [email protected]
+expression: "&result"
+source: crates/ra_hir/src/ty/tests.rs
+---
+[11; 80) '{     ...x)]; }': ()
+[21; 22) 'x': &&[unknown]
+[25; 32) 'unknown': &&[unknown]
+[42; 43) 'y': &&[unknown]
+[46; 53) 'unknown': &&[unknown]
+[59; 77) '[(x, y..., &x)]': [(&&[unknown], &&[unknown])]
+[60; 66) '(x, y)': (&&[unknown], &&[unknown])
+[61; 62) 'x': &&[unknown]
+[64; 65) 'y': &&[unknown]
+[68; 76) '(&y, &x)': (&&&[unknown], &&&[unknown])
+[69; 71) '&y': &&&[unknown]
+[70; 71) 'y': &&[unknown]
+[73; 75) '&x': &&&[unknown]
+[74; 75) 'x': &&[unknown]
+
diff --git a/crates/ra_hir/src/ty/tests.rs b/crates/ra_hir/src/ty/tests.rs
index e1165f682..e34daa0f7 100644
--- a/crates/ra_hir/src/ty/tests.rs
+++ b/crates/ra_hir/src/ty/tests.rs
@@ -562,6 +562,33 @@ fn quux() {
     );
 }
 
+#[test]
+fn recursive_vars() {
+    check_inference(
+        "recursive_vars",
+        r#"
+fn test() {
+    let y = unknown;
+    [y, &y];
+}
+"#,
+    );
+}
+
+#[test]
+fn recursive_vars_2() {
+    check_inference(
+        "recursive_vars_2",
+        r#"
+fn test() {
+    let x = unknown;
+    let y = unknown;
+    [(x, y), (&y, &x)];
+}
+"#,
+    );
+}
+
 fn infer(content: &str) -> String {
     let (db, _, file_id) = MockDatabase::with_single_file(content);
     let source_file = db.parse(file_id);