[clang-tidy] Ignore default arguments in modernize-default-member-init

Summary:
Default member initializers cannot refer to constructor parameters, but modernize-default-member-init was trying to when the default constructor had default arguments.

Change the check to ignore default arguments to the default constructor.

Fixes PR31524.

Reviewers: alexfh, aaron.ballman

Subscribers: cfe-commits, JDevlieghere, Eugene.Zelenko

Differential Revision: https://reviews.llvm.org/D28287

llvm-svn: 290972

2 files changed, 7 insertions, 1 deletions

diff --git a/clang-tools-extra/clang-tidy/modernize/UseDefaultMemberInitCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseDefaultMemberInitCheck.cpp
index c8e92043381..d0d4c657e57 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseDefaultMemberInitCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseDefaultMemberInitCheck.cpp
@@ -158,7 +158,7 @@ void UseDefaultMemberInitCheck::registerMatchers(MatchFinder *Finder) {
             unaryOperator(anyOf(hasOperatorName("+"), hasOperatorName("-")),
                           hasUnaryOperand(floatLiteral())),
             cxxBoolLiteral(), cxxNullPtrLiteralExpr(), implicitValueInitExpr(),
-            declRefExpr());
+            declRefExpr(to(enumConstantDecl())));
 
   Finder->addMatcher(
       cxxConstructorDecl(
diff --git a/clang-tools-extra/test/clang-tidy/modernize-use-default-member-init.cpp b/clang-tools-extra/test/clang-tidy/modernize-use-default-member-init.cpp
index 5844cdff990..febcce514cb 100644
--- a/clang-tools-extra/test/clang-tidy/modernize-use-default-member-init.cpp
+++ b/clang-tools-extra/test/clang-tidy/modernize-use-default-member-init.cpp
@@ -221,6 +221,12 @@ struct NegativeNotDefaultInt
   int i;
 };
 
+struct NegativeDefaultArg
+{
+  NegativeDefaultArg(int i = 4) : i(i) {}
+  int i;
+};
+
 struct ExistingChar {
   ExistingChar(short) : e1(), e2(), e3(), e4() {}
   // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: member initializer for 'e1' is redundant [modernize-use-default-member-init]