[clang][NFC] Tests showing the problems with some uses of NamedDecl::getDeclName in diagnostics, SemaExpr.cpp part

clang/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p7.cpp

@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -verify %s
+// RUN: %clang_cc1 -std=c++17 -fsyntax-only -verify %s
 
 void h() {
   int i1 = 0;
@@ -16,4 +16,16 @@ void h() {
   const int i4 = 0;
   extern void h4(int x = sizeof(i4));         // ok, not odr-use
   extern void h5(int x = decltype(i4 + 4)()); // ok, not odr-use
+
+  union {
+    int i5;
+  };
+
+  extern void h6(int = i5);
+  // expected-error@-1 {{default argument references local variable '' of enclosing function}}
+
+  struct S { int i; };
+  auto [x] = S();
+
+  extern void h7(int = x); // FIXME: reject
 }

clang/test/SemaCXX/attr-unused.cpp

@@ -3,7 +3,17 @@
 namespace ns_unused { typedef int Int_unused __attribute__((unused)); }
 namespace ns_not_unused { typedef int Int_not_unused; }
 
+template <typename T> class C;
+template <> class __attribute__((unused)) C<int> {};
+
 void f() {
   ns_not_unused::Int_not_unused i1; // expected-warning {{unused variable}}
   ns_unused::Int_unused i0; // expected-warning {{'Int_unused' was marked unused but was used}}
+
+  union __attribute__((unused)) { // expected-warning {{'' was marked unused but was used}}
+    int i;
+  };
+  (void) i;
+
+  C<int>(); // expected-warning {{'C' was marked unused but was used}}
 }

clang/test/SemaCXX/default2.cpp

@@ -117,6 +117,12 @@ class C2 {
   static int f(int = 10); // expected-note{{default argument declared here}}
 };
 
+template <typename T> class C3;
+template <> class C3<int> {
+  static void g(int = f()); // expected-error {{use of default argument to function 'f' that is declared later in class 'C3'}}
+  static int f(int = 10); // expected-note {{default argument declared here}}
+};
+
 // Make sure we actually parse the default argument for an inline definition
 class XX {
   void A(int length = -1 ) {  } 

clang/test/SemaCXX/incomplete-call.cpp

@@ -1,7 +1,8 @@
 // RUN: %clang_cc1 -fsyntax-only -verify %s
-struct A; // expected-note 14 {{forward declaration of 'A'}}
+struct A; // expected-note 15 {{forward declaration of 'A'}}
 
 A f(); // expected-note {{'f' declared here}}
+template <typename T> A ft(T); // expected-note {{'ft' declared here}}
 
 struct B {
   A f(); // expected-note {{'f' declared here}}
@@ -38,7 +39,8 @@ void g() {
   
   A (B::*mfp)() = 0;
   (b.*mfp)(); // expected-error {{calling function with incomplete return type 'A'}}
-  
+
+  ft(42); // expected-error {{calling 'ft' with incomplete return type 'A'}}
 }
 
 

clang/test/SemaCXX/lambda-expressions.cpp

@@ -649,3 +649,14 @@ void Run(const int& points) {
 void operator_parens() {
   [&](int x){ operator()(); }(0); // expected-error {{undeclared 'operator()'}}
 }
+
+namespace captured_name {
+void Test() {
+  union {           // expected-note {{'' declared here}}
+    int i;
+  };
+  [] { return i; }; // expected-error {{variable '' cannot be implicitly captured in a lambda with no capture-default specified}}
+                    // expected-note@-1 {{lambda expression begins here}}
+
+}
+};