[clang-tidy] modernize-use-equals-default avoid adding redundant semicolons

Summary:
`modernize-use-equals-default` replaces default constructors/destructors with `= default;`. When the optional semicolon after a member function is present, this results in two consecutive semicolons.

This patch checks to see if the next non-comment token after the code to be replaced is a semicolon, and if so offers a replacement of `= default` rather than `= default;`.

This patch adds trailing comments and semicolons to about 5 existing tests.

Reviewers: malcolm.parsons, angelgarcia, aaron.ballman, alexfh

Patch by: poelmanc

Subscribers: MyDeveloperDay, JonasToth, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D70144

1 files changed, 10 insertions, 2 deletions

diff --git a/clang-tools-extra/clang-tidy/modernize/UseEqualsDefaultCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseEqualsDefaultCheck.cpp
index 991eada514d..0309fa8d0a3 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseEqualsDefaultCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseEqualsDefaultCheck.cpp
@@ -10,6 +10,7 @@
 #include "clang/AST/ASTContext.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
 #include "clang/Lex/Lexer.h"
+#include "../utils/LexerUtils.h"
 
 using namespace clang::ast_matchers;
 
@@ -302,9 +303,16 @@ void UseEqualsDefaultCheck::check(const MatchFinder::MatchResult &Result) {
   auto Diag = diag(Location, "use '= default' to define a trivial " +
                                  SpecialFunctionName);
 
-  if (ApplyFix)
-    Diag << FixItHint::CreateReplacement(Body->getSourceRange(), "= default;")
+  if (ApplyFix) {
+    // Skipping comments, check for a semicolon after Body->getSourceRange()
+    Optional<Token> Token = utils::lexer::findNextTokenSkippingComments(
+        Body->getSourceRange().getEnd().getLocWithOffset(1),
+        Result.Context->getSourceManager(), Result.Context->getLangOpts());
+    StringRef Replacement =
+        Token && Token->is(tok::semi) ? "= default" : "= default;";
+    Diag << FixItHint::CreateReplacement(Body->getSourceRange(), Replacement)
          << RemoveInitializers;
+  }
 }
 
 } // namespace modernize