[all-commits] [llvm/llvm-project] a247ba: Suggest typo corrections for preprocessor directives

[Ken Matsui via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: a247ba9d15635d96225ef39c8c150c08f492e70a
      https://github.com/llvm/llvm-project/commit/a247ba9d15635d96225ef39c8c150c08f492e70a
  Author: Ken Matsui <vcs at kmatsui.me>
  Date:   2022-05-13 (Fri, 13 May 2022)

  Changed paths:
    M clang/docs/ReleaseNotes.rst
    M clang/include/clang/Basic/DiagnosticLexKinds.td
    M clang/include/clang/Lex/Preprocessor.h
    M clang/lib/Lex/PPDirectives.cpp
    A clang/test/Preprocessor/suggest-typoed-directive.c

  Log Message:
  -----------
  Suggest typo corrections for preprocessor directives

When a preprocessor directive is unknown outside of a skipped
conditional block, we give an error diagnostic because we don't know
how to proceed with preprocessing. But when the directive is in a
skipped conditional block, we would not diagnose it on the theory that
the directive may be known to an implementation other than Clang.

Now, for unknown directives inside a skipped conditional block, we
diagnose the unknown directive as a warning if it is sufficiently
similar to a directive specific to preprocessor conditional blocks. For
example, we'll warn about `#esle` and suggest `#else` but we won't warn
about `#progma` because it's not a directive specific to preprocessor
conditional blocks.

Fixes #51598

Differential Revision: https://reviews.llvm.org/D124726