swiftlang/swift

[SR-10295] Unexpected ambiguity error when trying to use variable with the same name as an instance member

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#52,695 opened on Apr 3, 2019

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Description
Previous ID SR-10295
Radar rdar://problem/45572606
Original Reporter @xedin
Type Bug
Status In Progress
Resolution
Votes 0
Component/s Compiler
Labels Bug, DiagnosticsQoI, StarterBug
Assignee @theblixguy
Priority Medium

md5: 350070c7174a52610d975e704164ed3e

relates to:

  • SR-1846 "Variable used in its own initial value" error when using a function (not a variable) of the same name

Issue Description:

Consider following example:

struct S {
  func foo(x: Int) {}

  func bar() {
    let foo = foo(x: 42)
  }
}

It produces following error:

variable used within its own initial value

Which doesn't really make much sense, instead it should produce an error which suggests to add `self.` before method or variable use e.g. `let foo = self.foo(x: 42)`

Contributor guide

Tech stack
swift
Domain
backenddeveloper experience
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
blocked
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Swift programmingfamiliarity with compiler diagnostics
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
Investigate the compiler's name resolution in the Swift compiler, likely in files like `lib/Sema/NameBinding.cpp` or `lib/Sema/MiscDiagnostics.cpp`. The goal is to modify the diagnostic when a local variable shadows an instance member: instead of 'variable used within its own initial value', produce a suggestion to use `self.` prefix. Check related issue SR 1846 for context. The fix should be localized to a single diagnostic message.