Make modernize-use-default tolerant of delayed template parsing; this code was previously causing failed assertions because dyn_cast was being passed a null pointer due to the delay-parsed body.

llvm-svn: 258356

clang-tools-extra/clang-tidy/modernize/UseDefaultCheck.cpp

@@ -272,6 +272,7 @@ void UseDefaultCheck::check(const MatchFinder::MatchResult &Result) {
   // that are not user-provided (automatically generated).
   if (SpecialFunctionDecl->isDeleted() ||
       SpecialFunctionDecl->isExplicitlyDefaulted() ||
+      SpecialFunctionDecl->isLateTemplateParsed() ||
       !SpecialFunctionDecl->isUserProvided() || !SpecialFunctionDecl->hasBody())
     return;
 

clang-tools-extra/test/clang-tidy/modernize-use-default-delayed.cpp

@@ -0,0 +1,8 @@
+// RUN: clang-tidy %s -checks=-*,modernize-use-default -- -std=c++11 -fdelayed-template-parsing -fexceptions | count 0
+// Note: this test expects no diagnostics, but FileCheck cannot handle that,
+// hence the use of | count 0.
+
+template <typename Ty>
+struct S {
+  S<Ty>& operator=(const S<Ty>&) { return *this; }
+};