Index: clang-tools-extra/trunk/clang-tidy/utils/TypeTraits.cpp
===================================================================
--- clang-tools-extra/trunk/clang-tidy/utils/TypeTraits.cpp
+++ clang-tools-extra/trunk/clang-tidy/utils/TypeTraits.cpp
@@ -62,8 +62,10 @@
   if (ClassDecl->hasTrivialDefaultConstructor())
     return true;
 
-  // If all its fields are trivially constructible.
+  // If all its fields are trivially constructible and have no default initializers.
   for (const FieldDecl *Field : ClassDecl->fields()) {
+    if (Field->hasInClassInitializer())
+      return false;
     if (!isTriviallyDefaultConstructible(Field->getType(), Context))
       return false;
   }
Index: clang-tools-extra/trunk/test/clang-tidy/cppcoreguidelines-pro-type-member-init.cpp
===================================================================
--- clang-tools-extra/trunk/test/clang-tidy/cppcoreguidelines-pro-type-member-init.cpp
+++ clang-tools-extra/trunk/test/clang-tidy/cppcoreguidelines-pro-type-member-init.cpp
@@ -73,6 +73,11 @@
   NegativeInClassInitialized() {}
 };
 
+struct NegativeInClassInitializedDefaulted {
+  int F = 0;
+  NegativeInClassInitializedDefaulted() = default;
+};
+
 struct NegativeConstructorDelegated {
   int F;
 
@@ -367,3 +372,8 @@
   PositiveIndirectMember() {}
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: constructor does not initialize these fields: A
 };
+
+void Bug30487()
+{
+  NegativeInClassInitializedDefaulted s;
+}