Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Fix lambda return type inference #793

Merged
merged 3 commits into from
Oct 16, 2023
Merged

Fix lambda return type inference #793

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
2312035
Fix lambda return type inference
swernli Oct 15, 2023
4dc67db
Fix inner return test
swernli Oct 15, 2023
dbd368e
fix formatting
swernli Oct 15, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
9 changes: 5 additions & 4 deletions compiler/qsc_frontend/src/typeck/rules.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -331,16 +331,17 @@ impl<'a> Context<'a> {
let prev_ret_ty = self.return_ty.take();
let output_ty = self.inferrer.fresh_ty(TySource::not_divergent(body.span));
self.return_ty = Some(output_ty);
let body_ty = self.infer_expr(body).ty;
let body_partial = self.infer_expr(body);
let output_ty = self
.return_ty
.take()
.expect("return type should be present");
self.return_ty = prev_ret_ty;
if body_ty != Ty::UNIT {
// Only when the type of the body is not `UNIT` do we need to unify with the inferred output type.
if !body_partial.diverges {
// Only when the type of the body converges do we need to unify with the inferred output type.
// Otherwise we'd get spurious errors from lambdas that use explicit return-expr rather than implicit.
self.inferrer.eq(body.span, output_ty.clone(), body_ty);
self.inferrer
.eq(body.span, output_ty.clone(), body_partial.ty);
}
converge(Ty::Arrow(Box::new(Arrow {
kind: convert::callable_kind_from_ast(*kind),
Expand Down
98 changes: 96 additions & 2 deletions compiler/qsc_frontend/src/typeck/tests.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2352,8 +2352,8 @@ fn lambda_inner_return() {
#12 54-55 "f" : (Unit -> Int)
#14 58-98 "() -> {\n return 42;\n }" : (Unit -> Int)
#15 58-60 "()" : Unit
#16 64-98 "{\n return 42;\n }" : Int
#17 64-98 "{\n return 42;\n }" : Int
#16 64-98 "{\n return 42;\n }" : Unit
#17 64-98 "{\n return 42;\n }" : Unit
#19 78-87 "return 42" : Unit
#20 85-87 "42" : Int
#22 112-113 "r" : Int
Expand All @@ -2364,6 +2364,100 @@ fn lambda_inner_return() {
);
}

#[test]
fn lambda_inner_return_without_call_ambiguous() {
check(
indoc! {"
namespace A {
function Foo() : Unit {
let f = (a, b) -> {
return a + b;
};
}
}
"},
"",
&expect![[r#"
#6 30-32 "()" : Unit
#10 40-112 "{\n let f = (a, b) -> {\n return a + b;\n };\n }" : Unit
#12 54-55 "f" : ((?2, ?2) -> ?2)
#14 58-105 "(a, b) -> {\n return a + b;\n }" : ((?2, ?2) -> ?2)
#15 58-64 "(a, b)" : (?2, ?2)
#16 59-60 "a" : ?2
#18 62-63 "b" : ?2
#20 68-105 "{\n return a + b;\n }" : Unit
#21 68-105 "{\n return a + b;\n }" : Unit
#23 82-94 "return a + b" : Unit
#24 89-94 "a + b" : ?2
#25 89-90 "a" : ?2
#28 93-94 "b" : ?2
Error(Type(Error(AmbiguousTy(Span { lo: 62, hi: 63 }))))
"#]],
);
}

#[test]
fn lambda_implicit_return_without_call_ambiguous() {
check(
indoc! {"
namespace A {
function Foo() : Unit {
let f = (a, b) -> {
a + b
};
}
}
"},
"",
&expect![[r#"
#6 30-32 "()" : Unit
#10 40-104 "{\n let f = (a, b) -> {\n a + b\n };\n }" : Unit
#12 54-55 "f" : ((?2, ?2) -> ?2)
#14 58-97 "(a, b) -> {\n a + b\n }" : ((?2, ?2) -> ?2)
#15 58-64 "(a, b)" : (?2, ?2)
#16 59-60 "a" : ?2
#18 62-63 "b" : ?2
#20 68-97 "{\n a + b\n }" : ?2
#21 68-97 "{\n a + b\n }" : ?2
#23 82-87 "a + b" : ?2
#24 82-83 "a" : ?2
#27 86-87 "b" : ?2
Error(Type(Error(AmbiguousTy(Span { lo: 62, hi: 63 }))))
"#]],
);
}

#[test]
fn lambda_implicit_unit_return() {
check(
indoc! {"
namespace A {
function Foo() : Unit {
let f = (a, b) -> {};
f(1, 2);
}
}
"},
"",
&expect![[r#"
#6 30-32 "()" : Unit
#10 40-94 "{\n let f = (a, b) -> {};\n f(1, 2);\n }" : Unit
#12 54-55 "f" : ((Int, Int) -> Unit)
#14 58-70 "(a, b) -> {}" : ((Int, Int) -> Unit)
#15 58-64 "(a, b)" : (Int, Int)
#16 59-60 "a" : Int
#18 62-63 "b" : Int
#20 68-70 "{}" : Unit
#21 68-70 "{}" : Unit
#23 80-87 "f(1, 2)" : Unit
#24 80-81 "f" : ((Int, Int) -> Unit)
#27 81-87 "(1, 2)" : (Int, Int)
#28 82-83 "1" : Int
#29 85-86 "2" : Int
"#]],
);
}

#[test]
fn lambda_adj() {
check(
Expand Down