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authorUnreal Hoang <[email protected]>2019-07-20 12:11:18 +0100
committerUnreal Hoang <[email protected]>2019-07-20 12:12:19 +0100
commitbacf926a77a3e4040ccaf64cce1b1517e41a8d47 (patch)
tree0b979a84ccd68739dab8cc6d2aa1294611a1d7de /crates
parent5ac9f5cdc7a88dcb9545d2e150780c8edee83b06 (diff)
infer type for await
by projecting inner_ty to Future::Output alias
Diffstat (limited to 'crates')
-rw-r--r--crates/ra_hir/src/name.rs3
-rw-r--r--crates/ra_hir/src/ty/infer.rs42
-rw-r--r--crates/ra_hir/src/ty/tests.rs35
3 files changed, 78 insertions, 2 deletions
diff --git a/crates/ra_hir/src/name.rs b/crates/ra_hir/src/name.rs
index c589f8aba..6d14eea8e 100644
--- a/crates/ra_hir/src/name.rs
+++ b/crates/ra_hir/src/name.rs
@@ -118,6 +118,9 @@ pub(crate) const ITEM: Name = Name::new(SmolStr::new_inline_from_ascii(4, b"Item
118pub(crate) const OPS: Name = Name::new(SmolStr::new_inline_from_ascii(3, b"ops")); 118pub(crate) const OPS: Name = Name::new(SmolStr::new_inline_from_ascii(3, b"ops"));
119pub(crate) const TRY: Name = Name::new(SmolStr::new_inline_from_ascii(3, b"Try")); 119pub(crate) const TRY: Name = Name::new(SmolStr::new_inline_from_ascii(3, b"Try"));
120pub(crate) const OK: Name = Name::new(SmolStr::new_inline_from_ascii(2, b"Ok")); 120pub(crate) const OK: Name = Name::new(SmolStr::new_inline_from_ascii(2, b"Ok"));
121pub(crate) const FUTURE_MOD: Name = Name::new(SmolStr::new_inline_from_ascii(6, b"future"));
122pub(crate) const FUTURE_TYPE: Name = Name::new(SmolStr::new_inline_from_ascii(6, b"Future"));
123pub(crate) const OUTPUT: Name = Name::new(SmolStr::new_inline_from_ascii(6, b"Output"));
121 124
122fn resolve_name(text: &SmolStr) -> SmolStr { 125fn resolve_name(text: &SmolStr) -> SmolStr {
123 let raw_start = "r#"; 126 let raw_start = "r#";
diff --git a/crates/ra_hir/src/ty/infer.rs b/crates/ra_hir/src/ty/infer.rs
index 6eae595a9..a82dff711 100644
--- a/crates/ra_hir/src/ty/infer.rs
+++ b/crates/ra_hir/src/ty/infer.rs
@@ -1114,8 +1114,24 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
1114 .unwrap_or(Ty::Unknown); 1114 .unwrap_or(Ty::Unknown);
1115 self.insert_type_vars(ty) 1115 self.insert_type_vars(ty)
1116 } 1116 }
1117 Expr::Await { .. } => { 1117 Expr::Await { expr } => {
1118 Ty::Unknown 1118 let inner_ty = self.infer_expr(*expr, &Expectation::none());
1119 let ty = match self.resolve_future_future_output() {
1120 Some(future_future_output_alias) => {
1121 let ty = self.new_type_var();
1122 let projection = ProjectionPredicate {
1123 ty: ty.clone(),
1124 projection_ty: ProjectionTy {
1125 associated_ty: future_future_output_alias,
1126 parameters: vec![inner_ty].into(),
1127 },
1128 };
1129 self.obligations.push(Obligation::Projection(projection));
1130 self.resolve_ty_as_possible(&mut vec![], ty)
1131 }
1132 None => Ty::Unknown,
1133 };
1134 ty
1119 } 1135 }
1120 Expr::Try { expr } => { 1136 Expr::Try { expr } => {
1121 let inner_ty = self.infer_expr(*expr, &Expectation::none()); 1137 let inner_ty = self.infer_expr(*expr, &Expectation::none());
@@ -1371,6 +1387,28 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
1371 _ => None, 1387 _ => None,
1372 } 1388 }
1373 } 1389 }
1390
1391 fn resolve_future_future_output(&self) -> Option<TypeAlias> {
1392 let future_future_path = Path {
1393 kind: PathKind::Abs,
1394 segments: vec![
1395 PathSegment { name: name::STD, args_and_bindings: None },
1396 PathSegment { name: name::FUTURE_MOD, args_and_bindings: None },
1397 PathSegment { name: name::FUTURE_TYPE, args_and_bindings: None },
1398 ],
1399 };
1400
1401 match self
1402 .resolver
1403 .resolve_path_segments(self.db, &future_future_path)
1404 .into_fully_resolved()
1405 {
1406 PerNs { types: Some(Def(Trait(trait_))), .. } => {
1407 Some(trait_.associated_type_by_name(self.db, name::OUTPUT)?)
1408 }
1409 _ => None,
1410 }
1411 }
1374} 1412}
1375 1413
1376/// The ID of a type variable. 1414/// The ID of a type variable.
diff --git a/crates/ra_hir/src/ty/tests.rs b/crates/ra_hir/src/ty/tests.rs
index 265740e54..d4bfcb888 100644
--- a/crates/ra_hir/src/ty/tests.rs
+++ b/crates/ra_hir/src/ty/tests.rs
@@ -21,6 +21,41 @@ use crate::{
21// update the snapshots. 21// update the snapshots.
22 22
23#[test] 23#[test]
24fn infer_await() {
25 let (mut db, pos) = MockDatabase::with_position(
26 r#"
27//- /main.rs
28
29struct IntFuture;
30
31impl Future for IntFuture {
32 type Output = u64;
33}
34
35fn test() {
36 let r = IntFuture;
37 let v = r.await;
38 v<|>;
39}
40
41//- /std.rs
42#[prelude_import] use future::*;
43mod future {
44 trait Future {
45 type Output;
46 }
47}
48
49"#,
50 );
51 db.set_crate_graph_from_fixture(crate_graph! {
52 "main": ("/main.rs", ["std"]),
53 "std": ("/std.rs", []),
54 });
55 assert_eq!("u64", type_at_pos(&db, pos));
56}
57
58#[test]
24fn infer_try() { 59fn infer_try() {
25 let (mut db, pos) = MockDatabase::with_position( 60 let (mut db, pos) = MockDatabase::with_position(
26 r#" 61 r#"