[clang-tidy] google-explicit-constructor: don't match in template instantiations

This helps avoiding false positives related to the recently added
std::initializer_list<> handling.

llvm-svn: 222981

clang-tools-extra/clang-tidy/google/ExplicitConstructorCheck.cpp

@@ -19,7 +19,8 @@ namespace clang {
 namespace tidy {
 
 void ExplicitConstructorCheck::registerMatchers(MatchFinder *Finder) {
-  Finder->addMatcher(constructorDecl().bind("ctor"), this);
+  Finder->addMatcher(constructorDecl(unless(isInstantiated())).bind("ctor"),
+                     this);
 }
 
 // Looks for the token matching the predicate and returns the range of the found

clang-tools-extra/test/clang-tidy/google-explicit-constructor.cpp

@@ -78,3 +78,21 @@ struct C {
   C(const initializer_list<unsigned> &list2) {}
   C(initializer_list<unsigned> &&list3) {}
 };
+
+struct D {
+  template <typename T>
+  explicit D(T t) {}
+};
+
+template <typename T>
+struct E {
+  explicit E(T t) {}
+  template <typename U>
+  explicit E(U u) {}
+};
+
+void f(std::initializer_list<int> list) {
+  D d(list);
+  E<decltype(list)> e(list);
+  E<int> e2(list);
+}