[clang-tidy] Preserve comments and preprocessor directives when simplifying boolean expressions

This changeset still emits the diagnostic that the expression could be simplified, but it doesn't generate any fix-its that would lose comments or preprocessor directives within the text that would be replaced.

Fixes PR25842

Reviewers: alexfh

Subscribers: xazax.hun, cfe-commits

Patch by Richard Thomson! (+a naming style fix)

Differential Revision: http://reviews.llvm.org/D15737

llvm-svn: 256492
diff --git a/clang-tools-extra/clang-tidy/readability/SimplifyBooleanExprCheck.h b/clang-tools-extra/clang-tidy/readability/SimplifyBooleanExprCheck.h
index e3a106d..c74e6c4 100644
--- a/clang-tools-extra/clang-tidy/readability/SimplifyBooleanExprCheck.h
+++ b/clang-tools-extra/clang-tidy/readability/SimplifyBooleanExprCheck.h
@@ -154,6 +154,10 @@
       const ast_matchers::MatchFinder::MatchResult &Result,
       const CompoundStmt *Compound, bool Negated = false);
 
+  void issueDiag(const ast_matchers::MatchFinder::MatchResult &Result,
+                 SourceLocation Loc, StringRef Description,
+                 SourceRange ReplacementRange, StringRef Replacement);
+
   const bool ChainedConditionalReturn;
   const bool ChainedConditionalAssignment;
 };