Missing fix-it when opaque property type is inferred

[natecook1000]

Description
When the type of a variable or property is inferred as an opaque type, the compiler emits an error to that effect:

Property definition has inferred type 'some Proto', involving the 'some' return type of another declaration

Steps to reproduce
When compiling this code, the last line has the above error attached.:

protocol Proto {}
struct Concrete: Proto {}
func getProto() -> some Proto { Concrete() }

let value = getProto() // error

Expected behavior
Since the fix is straightforward and included in the error message, the compiler should offer a fixit that would rectify the problem:

let value: some Proto = getProto()

Environment

• Swift compiler version info Apple Swift version 5.9 (swiftlang-5.9.0.128.108 clang-1500.0.40.1) Target: arm64-apple-macosx14.0

[AnthonyLatsis]

This compiles on the main branch. @hborla Is this a regression?

[natecook1000]

Gah, I thought I had tested this on my latest toolchain, but I had not. Verified working on this version of Swift:

Apple Swift version 5.9-dev (LLVM 2b5ff47e44b059c, Swift f177be06ab5a206)
Target: arm64-apple-macosx14.0

[vanvoorden]

@natecook1000 I'm seeing a similar issue here… I'm trying to resolve a generic constraint using that opaque type. For some reason I seem to be breaking when I'm creating those variables inside the scope of a struct (but not when I'm creating those variables outside the struct). Any ideas or workarounds for that? Thanks!

protocol Proto {}
struct Concrete: Proto {}
func getProto() -> some Proto { Concrete() }

let value = getProto()

struct Wrapper<P: Proto> {
  let value: P
  
  init(_ wrappedValue: P) {
    self.value = wrappedValue
  }
  
  var wrappedValue: P {
    self.value
  }
}

let w1 = Wrapper(getProto())

let w2 = Wrapper(value)

struct S1 {
  let w1 = Wrapper(getProto())
  //  Property definition has inferred type 'Wrapper<some Proto>', involving the 'some' return type of another declaration
  let w2 = Wrapper(value)
  //  Property definition has inferred type 'Wrapper<some Proto>', involving the 'some' return type of another declaration
}

I tested this and saw the same error on the three latest toolchains:

• Apple Swift version 5.9.2-dev (LLVM 2b42c5ce063a374, Swift 9067148bc9c9a72)
• Apple Swift version 5.10-dev (LLVM 551823b7474ea05, Swift 3e816f55ab4b4d4)
• Apple Swift version 5.11-dev (LLVM 79aab1b6aed58d0, Swift fd9726839309a33)

[vanvoorden]

@natecook1000 @AnthonyLatsis I'm still unable to build that last example on 5.10 and 6.0. Are there any other open tasks for similar issues I can follow along and watch for? Thanks!

[AnthonyLatsis]

Reopening with this test case:

func foo() -> some Equatable { 0 }

struct S1 {
  let w0 = foo()
}

Context: #73661 (comment)

[Androp0v]

Mind if I take a shot at this? 👀