Merge #864

864: Fix handling of generics in tuple variants and refactor a bit r=matklad a=flodiebold

(The problem was that we created separate substitutions for the return value, so we lost the connection between the type arguments in the constructor call and the type arguments of the result.)

Also make them display a tiny bit nicer.

Fixes #860.

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

3 files changed, 47 insertions, 3 deletions

diff --git a/crates/ra_hir/src/ty/snapshots/tests__infer_struct.snap b/crates/ra_hir/src/ty/snapshots/tests__infer_struct.snap
index 294186b06..32f1fa108 100644
--- a/crates/ra_hir/src/ty/snapshots/tests__infer_struct.snap
+++ b/crates/ra_hir/src/ty/snapshots/tests__infer_struct.snap
@@ -1,19 +1,19 @@
 ---
-created: "2019-02-17T16:16:58.863630956Z"
+created: "2019-02-20T21:31:12.910924715Z"
 creator: [email protected]
 source: crates/ra_hir/src/ty/tests.rs
 expression: "&result"
 ---
 [72; 154) '{     ...a.c; }': ()
 [82; 83) 'c': C
-[86; 87) 'C': fn C(usize) -> C
+[86; 87) 'C': C(usize) -> C
 [86; 90) 'C(1)': C
 [88; 89) '1': usize
 [96; 97) 'B': B
 [107; 108) 'a': A
 [114; 133) 'A { b:...C(1) }': A
 [121; 122) 'B': B
-[127; 128) 'C': fn C(usize) -> C
+[127; 128) 'C': C(usize) -> C
 [127; 131) 'C(1)': C
 [129; 130) '1': usize
 [139; 140) 'a': A
diff --git a/crates/ra_hir/src/ty/snapshots/tests__infer_tuple_struct_generics.snap b/crates/ra_hir/src/ty/snapshots/tests__infer_tuple_struct_generics.snap
new file mode 100644
index 000000000..783795cfd
--- /dev/null
+++ b/crates/ra_hir/src/ty/snapshots/tests__infer_tuple_struct_generics.snap
@@ -0,0 +1,23 @@
+---
+created: "2019-02-20T21:31:12.911275141Z"
+creator: [email protected]
+source: crates/ra_hir/src/ty/tests.rs
+expression: "&result"
+---
+[77; 185) '{     ...one; }': ()
+[83; 84) 'A': A<i32>(T) -> A<T>
+[83; 88) 'A(42)': A<i32>
+[85; 87) '42': i32
+[94; 95) 'A': A<u128>(T) -> A<T>
+[94; 103) 'A(42u128)': A<u128>
+[96; 102) '42u128': u128
+[109; 113) 'Some': Some<&str>(T) -> Option<T>
+[109; 118) 'Some("x")': Option<&str>
+[114; 117) '"x"': &str
+[124; 136) 'Option::Some': Some<&str>(T) -> Option<T>
+[124; 141) 'Option...e("x")': Option<&str>
+[137; 140) '"x"': &str
+[147; 151) 'None': Option<[unknown]>
+[161; 162) 'x': Option<i64>
+[178; 182) 'None': Option<i64>
+
diff --git a/crates/ra_hir/src/ty/tests.rs b/crates/ra_hir/src/ty/tests.rs
index 4ab442b8a..3affcb4fe 100644
--- a/crates/ra_hir/src/ty/tests.rs
+++ b/crates/ra_hir/src/ty/tests.rs
@@ -466,6 +466,27 @@ fn test(a1: A<u32>, i: i32) {
 }
 
 #[test]
+fn infer_tuple_struct_generics() {
+    check_inference(
+        "infer_tuple_struct_generics",
+        r#"
+struct A<T>(T);
+enum Option<T> { Some(T), None };
+use Option::*;
+
+fn test() {
+    A(42);
+    A(42u128);
+    Some("x");
+    Option::Some("x");
+    None;
+    let x: Option<i64> = None;
+}
+"#,
+    );
+}
+
+#[test]
 fn infer_generics_in_patterns() {
     check_inference(
         "infer_generics_in_patterns",