From 35c948ff4a36b9c031bda96f79b8bf9e0d5bda26 Mon Sep 17 00:00:00 2001 From: Florian Diebold Date: Tue, 25 May 2021 14:24:08 +0200 Subject: Fix lowering of FnOnce() without return type This should result in an implicit `-> ()`, not leaving out the binding. --- crates/hir_def/src/path/lower.rs | 27 +++++++++++++++------------ crates/hir_ty/src/tests/traits.rs | 32 +++++++++++++++++++++++++++----- 2 files changed, 42 insertions(+), 17 deletions(-) diff --git a/crates/hir_def/src/path/lower.rs b/crates/hir_def/src/path/lower.rs index 5d5dd9c8f..54ede7393 100644 --- a/crates/hir_def/src/path/lower.rs +++ b/crates/hir_def/src/path/lower.rs @@ -205,15 +205,14 @@ fn lower_generic_args_from_fn_path( ) -> Option { let mut args = Vec::new(); let mut bindings = Vec::new(); - if let Some(params) = params { - let mut param_types = Vec::new(); - for param in params.params() { - let type_ref = TypeRef::from_ast_opt(&ctx, param.ty()); - param_types.push(type_ref); - } - let arg = GenericArg::Type(TypeRef::Tuple(param_types)); - args.push(arg); + let params = params?; + let mut param_types = Vec::new(); + for param in params.params() { + let type_ref = TypeRef::from_ast_opt(&ctx, param.ty()); + param_types.push(type_ref); } + let arg = GenericArg::Type(TypeRef::Tuple(param_types)); + args.push(arg); if let Some(ret_type) = ret_type { let type_ref = TypeRef::from_ast_opt(&ctx, ret_type.ty()); bindings.push(AssociatedTypeBinding { @@ -221,10 +220,14 @@ fn lower_generic_args_from_fn_path( type_ref: Some(type_ref), bounds: Vec::new(), }); - } - if args.is_empty() && bindings.is_empty() { - None } else { - Some(GenericArgs { args, has_self_type: false, bindings }) + // -> () + let type_ref = TypeRef::Tuple(Vec::new()); + bindings.push(AssociatedTypeBinding { + name: name![Output], + type_ref: Some(type_ref), + bounds: Vec::new(), + }); } + Some(GenericArgs { args, has_self_type: false, bindings }) } diff --git a/crates/hir_ty/src/tests/traits.rs b/crates/hir_ty/src/tests/traits.rs index a5a2df54c..714f12937 100644 --- a/crates/hir_ty/src/tests/traits.rs +++ b/crates/hir_ty/src/tests/traits.rs @@ -3041,7 +3041,7 @@ fn infer_fn_trait_arg() { #[test] fn infer_box_fn_arg() { - // The type mismatch is a bug + // The type mismatch is because we don't define Unsize and CoerceUnsized check_infer_with_mismatches( r#" //- /lib.rs deps:std @@ -3095,16 +3095,16 @@ fn foo() { 478..576 '{ ...&s); }': () 488..489 's': Option 492..504 'Option::None': Option - 514..515 'f': Box)> + 514..515 'f': Box) -> ()> 549..562 'box (|ps| {})': Box<|{unknown}| -> ()> 554..561 '|ps| {}': |{unknown}| -> () 555..557 'ps': {unknown} 559..561 '{}': () - 568..569 'f': Box)> - 568..573 'f(&s)': FnOnce::Output), (&Option,)> + 568..569 'f': Box) -> ()> + 568..573 'f(&s)': () 570..572 '&s': &Option 571..572 's': Option - 549..562: expected Box)>, got Box<|{unknown}| -> ()> + 549..562: expected Box) -> ()>, got Box<|{unknown}| -> ()> "#]], ); } @@ -3571,3 +3571,25 @@ fn main() { "#]], ) } + +#[test] +fn fn_returning_unit() { + check_infer_with_mismatches( + r#" +#[lang = "fn_once"] +trait FnOnce { + type Output; +} + +fn test(f: F) { + let _: () = f(); +}"#, + expect![[r#" + 82..83 'f': F + 88..112 '{ ...f(); }': () + 98..99 '_': () + 106..107 'f': F + 106..109 'f()': () + "#]], + ); +} -- cgit v1.2.3