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Auto merge of #12063 - iDawer:ide.signature_help, r=Veykril
fix: Fall back to parameter definitions on error types in signature help
Fixes #10432
| -rw-r--r-- | crates/ide/src/signature_help.rs | 81 |
1 files changed, 55 insertions, 26 deletions
diff --git a/crates/ide/src/signature_help.rs b/crates/ide/src/signature_help.rs index 6dc8b3046c..4eca69033a 100644 --- a/crates/ide/src/signature_help.rs +++ b/crates/ide/src/signature_help.rs @@ -110,10 +110,12 @@ fn signature_help_for_call( SignatureHelp { doc: None, signature: String::new(), parameters: vec![], active_parameter }; let db = sema.db; + let mut fn_params = None; match callable.kind() { hir::CallableKind::Function(func) => { res.doc = func.docs(db).map(|it| it.into()); format_to!(res.signature, "fn {}", func.name(db)); + fn_params = Some(func.assoc_fn_params(db)); } hir::CallableKind::TupleStruct(strukt) => { res.doc = strukt.docs(db).map(|it| it.into()); @@ -137,7 +139,7 @@ fn signature_help_for_call( format_to!(res.signature, "{}", self_param) } let mut buf = String::new(); - for (pat, ty) in callable.params(db) { + for (idx, (pat, ty)) in callable.params(db).into_iter().enumerate() { buf.clear(); if let Some(pat) = pat { match pat { @@ -145,18 +147,31 @@ fn signature_help_for_call( Either::Right(pat) => format_to!(buf, "{}: ", pat), } } - format_to!(buf, "{}", ty.display(db)); + // APITs (argument position `impl Trait`s) are inferred as {unknown} as the user is + // in the middle of entering call arguments. + // In that case, fall back to render definitions of the respective parameters. + // This is overly conservative: we do not substitute known type vars + // (see FIXME in tests::impl_trait) and falling back on any unknowns. + match (ty.contains_unknown(), fn_params.as_deref()) { + (true, Some(fn_params)) => format_to!(buf, "{}", fn_params[idx].ty().display(db)), + _ => format_to!(buf, "{}", ty.display(db)), + } res.push_call_param(&buf); } } res.signature.push(')'); + let mut render = |ret_type: hir::Type| { + if !ret_type.is_unit() { + format_to!(res.signature, " -> {}", ret_type.display(db)); + } + }; match callable.kind() { + hir::CallableKind::Function(func) if callable.return_type().contains_unknown() => { + render(func.ret_type(db)) + } hir::CallableKind::Function(_) | hir::CallableKind::Closure => { - let ret_type = callable.return_type(); - if !ret_type.is_unit() { - format_to!(res.signature, " -> {}", ret_type.display(db)); - } + render(callable.return_type()) } hir::CallableKind::TupleStruct(_) | hir::CallableKind::TupleEnumVariant(_) => {} } @@ -420,8 +435,8 @@ fn foo<T, U: Copy + Display>(x: T, y: U) -> u32 fn bar() { foo($03, ); } "#, expect![[r#" - fn foo(x: i32, y: {unknown}) -> u32 - ^^^^^^ ------------ + fn foo(x: i32, y: U) -> u32 + ^^^^^^ ---- "#]], ); } @@ -434,7 +449,7 @@ fn foo<T>() -> T where T: Copy + Display {} fn bar() { foo($0); } "#, expect![[r#" - fn foo() -> {unknown} + fn foo() -> T "#]], ); } @@ -633,26 +648,21 @@ pub fn do_it() { fn test_fn_signature_with_docs_from_actix() { check( r#" -struct WriteHandler<E>; - -impl<E> WriteHandler<E> { - /// Method is called when writer emits error. - /// - /// If this method returns `ErrorAction::Continue` writer processing - /// continues otherwise stream processing stops. - fn error(&mut self, err: E, ctx: &mut Self::Context) -> Running { - Running::Stop - } - +trait Actor { + /// Actor execution context type + type Context; +} +trait WriteHandler<E> +where + Self: Actor +{ /// Method is called when writer finishes. /// /// By default this method stops actor's `Context`. - fn finished(&mut self, ctx: &mut Self::Context) { - ctx.stop() - } + fn finished(&mut self, ctx: &mut Self::Context) {} } -pub fn foo(mut r: WriteHandler<()>) { +fn foo(mut r: impl WriteHandler<()>) { r.finished($0); } "#, @@ -661,8 +671,8 @@ pub fn foo(mut r: WriteHandler<()>) { By default this method stops actor's `Context`. ------ - fn finished(&mut self, ctx: &mut {unknown}) - ^^^^^^^^^^^^^^^^^^^ + fn finished(&mut self, ctx: &mut <impl WriteHandler<()> as Actor>::Context) + ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ "#]], ); } @@ -1055,4 +1065,23 @@ fn f() { "#]], ); } + + #[test] + fn impl_trait() { + // FIXME: Substitute type vars in impl trait (`U` -> `i8`) + check( + r#" +trait Trait<T> {} +struct Wrap<T>(T); +fn foo<U>(x: Wrap<impl Trait<U>>) {} +fn f() { + foo::<i8>($0) +} +"#, + expect![[r#" + fn foo(x: Wrap<impl Trait<U>>) + ^^^^^^^^^^^^^^^^^^^^^^ + "#]], + ); + } } |