[PATCH] D52218: Warn on self-initializations

[Richard Trieu via Phabricator via cfe-commits]

rtrieu created this revision.

Improve some diagnostics around self-initialization.  The uninitialized checker does not warn on self-initialization, but does warn later if the variable is used.  GCC also has a -Winit-self which will enable a -Wuninitialized warning for self-initialized.  -Winit-self is active in -Wall

There's also the matter of the variable being const.  GCC -Wuninitialized will warn on a const self-initialized with or without -Winit-self.

This patch will make it so that const self-initialization is always warned on under -Wuninitialized.  Since Clang does not use warning flags to control other warnings, -Winit-self will be a new warning group for non-const self-initialized.  -Winit-self will also be in -Wall via -Wmost.

  // GCC - warn with -Wuninitialized and -Winit-self
  // Clang - no warning
  // Clang with patch - warn with -Winit-self
  void f1() {
    int x = x;
  }
  
  // GCC - warn with -Wuninitialized
  // Clang - no warning
  // Clang with patch - warn with -Wuninitialized
  void f2() {
    const int x = x;
  }




https://reviews.llvm.org/D52218

Files:
  include/clang/Basic/DiagnosticGroups.td
  include/clang/Basic/DiagnosticSemaKinds.td
  lib/Sema/AnalysisBasedWarnings.cpp
  lib/Sema/SemaDecl.cpp
  test/SemaCXX/uninitialized.cpp

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