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author | bors[bot] <bors[bot]@users.noreply.github.com> | 2019-01-11 22:49:32 +0000 |
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committer | bors[bot] <bors[bot]@users.noreply.github.com> | 2019-01-11 22:49:32 +0000 |
commit | cca39ebc24d3dfcfcbb2565843ee9f70891cb139 (patch) | |
tree | e2996f670efd50d346cfa8dd0f836bcb65aca4dc | |
parent | f60153ee9e1d598c170743633448aa3ede8cb72e (diff) | |
parent | 1212e59beed25d768bfaf7bb202aa955a87106e9 (diff) |
Merge #491
491: Fix assertion error in unification (hopefully) r=flodiebold a=flodiebold
Currently, all types that we handle during inference need to be resolved as far
as possible at the time. It's maybe too brittle of an invariant; I need to think
how we can do this better. This should fix #484 though, I hope (if
it's the same case as I managed to reproduce).
Co-authored-by: Florian Diebold <[email protected]>
-rw-r--r-- | crates/ra_hir/src/ty.rs | 40 | ||||
-rw-r--r-- | crates/ra_hir/src/ty/tests.rs | 12 | ||||
-rw-r--r-- | crates/ra_hir/src/ty/tests/data/bug_484.txt | 5 |
3 files changed, 50 insertions, 7 deletions
diff --git a/crates/ra_hir/src/ty.rs b/crates/ra_hir/src/ty.rs index 0c24a0652..2d533eb6a 100644 --- a/crates/ra_hir/src/ty.rs +++ b/crates/ra_hir/src/ty.rs | |||
@@ -18,6 +18,7 @@ mod primitive; | |||
18 | #[cfg(test)] | 18 | #[cfg(test)] |
19 | mod tests; | 19 | mod tests; |
20 | 20 | ||
21 | use std::borrow::Cow; | ||
21 | use std::ops::Index; | 22 | use std::ops::Index; |
22 | use std::sync::Arc; | 23 | use std::sync::Arc; |
23 | use std::{fmt, mem}; | 24 | use std::{fmt, mem}; |
@@ -671,7 +672,10 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> { | |||
671 | } | 672 | } |
672 | 673 | ||
673 | fn unify(&mut self, ty1: &Ty, ty2: &Ty) -> bool { | 674 | fn unify(&mut self, ty1: &Ty, ty2: &Ty) -> bool { |
674 | match (ty1, ty2) { | 675 | // try to resolve type vars first |
676 | let ty1 = self.resolve_ty_shallow(ty1); | ||
677 | let ty2 = self.resolve_ty_shallow(ty2); | ||
678 | match (&*ty1, &*ty2) { | ||
675 | (Ty::Unknown, ..) => true, | 679 | (Ty::Unknown, ..) => true, |
676 | (.., Ty::Unknown) => true, | 680 | (.., Ty::Unknown) => true, |
677 | (Ty::Bool, _) | 681 | (Ty::Bool, _) |
@@ -698,10 +702,12 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> { | |||
698 | .zip(ts2.iter()) | 702 | .zip(ts2.iter()) |
699 | .all(|(t1, t2)| self.unify(t1, t2)), | 703 | .all(|(t1, t2)| self.unify(t1, t2)), |
700 | (Ty::Infer(InferTy::TypeVar(tv1)), Ty::Infer(InferTy::TypeVar(tv2))) => { | 704 | (Ty::Infer(InferTy::TypeVar(tv1)), Ty::Infer(InferTy::TypeVar(tv2))) => { |
705 | // both type vars are unknown since we tried to resolve them | ||
701 | self.var_unification_table.union(*tv1, *tv2); | 706 | self.var_unification_table.union(*tv1, *tv2); |
702 | true | 707 | true |
703 | } | 708 | } |
704 | (Ty::Infer(InferTy::TypeVar(tv)), other) | (other, Ty::Infer(InferTy::TypeVar(tv))) => { | 709 | (Ty::Infer(InferTy::TypeVar(tv)), other) | (other, Ty::Infer(InferTy::TypeVar(tv))) => { |
710 | // the type var is unknown since we tried to resolve it | ||
705 | self.var_unification_table | 711 | self.var_unification_table |
706 | .union_value(*tv, TypeVarValue::Known(other.clone())); | 712 | .union_value(*tv, TypeVarValue::Known(other.clone())); |
707 | true | 713 | true |
@@ -746,6 +752,23 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> { | |||
746 | }) | 752 | }) |
747 | } | 753 | } |
748 | 754 | ||
755 | /// If `ty` is a type variable with known type, returns that type; | ||
756 | /// otherwise, return ty. | ||
757 | fn resolve_ty_shallow<'b>(&mut self, ty: &'b Ty) -> Cow<'b, Ty> { | ||
758 | match ty { | ||
759 | Ty::Infer(InferTy::TypeVar(tv)) => { | ||
760 | match self.var_unification_table.probe_value(*tv).known() { | ||
761 | Some(known_ty) => { | ||
762 | // The known_ty can't be a type var itself | ||
763 | Cow::Owned(known_ty.clone()) | ||
764 | } | ||
765 | _ => Cow::Borrowed(ty), | ||
766 | } | ||
767 | } | ||
768 | _ => Cow::Borrowed(ty), | ||
769 | } | ||
770 | } | ||
771 | |||
749 | /// Resolves the type completely; type variables without known type are | 772 | /// Resolves the type completely; type variables without known type are |
750 | /// replaced by Ty::Unknown. | 773 | /// replaced by Ty::Unknown. |
751 | fn resolve_ty_completely(&mut self, ty: Ty) -> Ty { | 774 | fn resolve_ty_completely(&mut self, ty: Ty) -> Ty { |
@@ -816,12 +839,15 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> { | |||
816 | // if let is desugared to match, so this is always simple if | 839 | // if let is desugared to match, so this is always simple if |
817 | self.infer_expr(*condition, &Expectation::has_type(Ty::Bool))?; | 840 | self.infer_expr(*condition, &Expectation::has_type(Ty::Bool))?; |
818 | let then_ty = self.infer_expr(*then_branch, expected)?; | 841 | let then_ty = self.infer_expr(*then_branch, expected)?; |
819 | if let Some(else_branch) = else_branch { | 842 | match else_branch { |
820 | self.infer_expr(*else_branch, expected)?; | 843 | Some(else_branch) => { |
821 | } else { | 844 | self.infer_expr(*else_branch, expected)?; |
822 | // no else branch -> unit | 845 | } |
823 | self.unify(&expected.ty, &Ty::unit()); // actually coerce | 846 | None => { |
824 | } | 847 | // no else branch -> unit |
848 | self.unify(&then_ty, &Ty::unit()); // actually coerce | ||
849 | } | ||
850 | }; | ||
825 | then_ty | 851 | then_ty |
826 | } | 852 | } |
827 | Expr::Block { statements, tail } => self.infer_block(statements, *tail, expected)?, | 853 | Expr::Block { statements, tail } => self.infer_block(statements, *tail, expected)?, |
diff --git a/crates/ra_hir/src/ty/tests.rs b/crates/ra_hir/src/ty/tests.rs index d8c0af326..815aecda7 100644 --- a/crates/ra_hir/src/ty/tests.rs +++ b/crates/ra_hir/src/ty/tests.rs | |||
@@ -230,6 +230,18 @@ fn test2(a1: *const A, a2: *mut A) { | |||
230 | ); | 230 | ); |
231 | } | 231 | } |
232 | 232 | ||
233 | #[test] | ||
234 | fn infer_bug_484() { | ||
235 | check_inference( | ||
236 | r#" | ||
237 | fn test() { | ||
238 | let x = if true {}; | ||
239 | } | ||
240 | "#, | ||
241 | "bug_484.txt", | ||
242 | ); | ||
243 | } | ||
244 | |||
233 | fn infer(content: &str) -> String { | 245 | fn infer(content: &str) -> String { |
234 | let (db, _, file_id) = MockDatabase::with_single_file(content); | 246 | let (db, _, file_id) = MockDatabase::with_single_file(content); |
235 | let source_file = db.source_file(file_id); | 247 | let source_file = db.source_file(file_id); |
diff --git a/crates/ra_hir/src/ty/tests/data/bug_484.txt b/crates/ra_hir/src/ty/tests/data/bug_484.txt new file mode 100644 index 000000000..300530551 --- /dev/null +++ b/crates/ra_hir/src/ty/tests/data/bug_484.txt | |||
@@ -0,0 +1,5 @@ | |||
1 | [11; 37) '{ l... {}; }': () | ||
2 | [20; 21) 'x': () | ||
3 | [24; 34) 'if true {}': () | ||
4 | [27; 31) 'true': bool | ||
5 | [32; 34) '{}': () | ||