14 files changed, 259 insertions, 26 deletions

diff --git a/include/clang/AST/Decl.h b/include/clang/AST/Decl.h
index 70edcbb222..ee3ddb09aa 100644
--- a/include/clang/AST/Decl.h
+++ b/include/clang/AST/Decl.h
@@ -648,12 +648,18 @@ public:
     Init = reinterpret_cast<Stmt *>(defarg);
   }
 
+  /// \brief Retrieve the source range that covers the entire default
+  /// argument.
+  SourceRange getDefaultArgRange() const;  
   void setUninstantiatedDefaultArg(Expr *arg) {
     Init = reinterpret_cast<UninstantiatedDefaultArgument *>(arg);
   }
   Expr *getUninstantiatedDefaultArg() {
     return (Expr *)Init.get<UninstantiatedDefaultArgument *>();
   }
+  const Expr *getUninstantiatedDefaultArg() const {
+    return (const Expr *)Init.get<UninstantiatedDefaultArgument *>();
+  }
 
   /// hasDefaultArg - Determines whether this parameter has a default argument,
   /// either parsed or not.
diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index f9f2f15af0..ab12463cc0 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -703,6 +703,13 @@ def err_param_default_argument_references_this : Error<
 def err_param_default_argument_nonfunc : Error<
   "default arguments can only be specified for parameters in a function "
   "declaration">;
+def err_param_default_argument_template_redecl : Error<
+  "default arguments cannot be added to a function template that has already "
+  "been declared">;
+def err_param_default_argument_member_template_redecl : Error<
+  "default arguments cannot be added to an out-of-line definition of a member "
+  "of a %select{class template|class template partial specialization|nested "
+  "class in a template}0">;
 def err_defining_default_ctor : Error<
   "cannot define the implicit default constructor for %0, because %select{base class|member}1 "
   "%2 does not have any default constructor">;
diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index 16936428f3..8fd6ebf5ee 100644
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -98,15 +98,25 @@ QualType ParmVarDecl::getOriginalType() const {
   return getType();
 }
 
-void VarDecl::setInit(ASTContext &C, Expr *I) {
-    if (EvaluatedStmt *Eval = Init.dyn_cast<EvaluatedStmt *>()) {
-      Eval->~EvaluatedStmt();
-      C.Deallocate(Eval);
-    }
+SourceRange ParmVarDecl::getDefaultArgRange() const {
+  if (const Expr *E = getInit())
+    return E->getSourceRange();
+  
+  if (const Expr *E = getUninstantiatedDefaultArg())
+    return E->getSourceRange();
+    
+  return SourceRange();
+}
 
-    Init = I;
+void VarDecl::setInit(ASTContext &C, Expr *I) {
+  if (EvaluatedStmt *Eval = Init.dyn_cast<EvaluatedStmt *>()) {
+    Eval->~EvaluatedStmt();
+    C.Deallocate(Eval);
   }
 
+  Init = I;
+}
+
 bool VarDecl::isExternC(ASTContext &Context) const {
   if (!Context.getLangOptions().CPlusPlus)
     return (getDeclContext()->isTranslationUnit() &&
diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index b3cef85d67..97d7b2f76d 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -241,7 +241,6 @@ bool Sema::MergeCXXFunctionDecl(FunctionDecl *New, FunctionDecl *Old) {
   bool Invalid = false;
 
   // C++ [dcl.fct.default]p4:
-  //
   //   For non-template functions, default arguments can be added in
   //   later declarations of a function in the same
   //   scope. Declarations in different scopes have completely
@@ -253,19 +252,71 @@ bool Sema::MergeCXXFunctionDecl(FunctionDecl *New, FunctionDecl *Old) {
   //   arguments supplied in this or previous declarations. A
   //   default argument shall not be redefined by a later
   //   declaration (not even to the same value).
+  //
+  // C++ [dcl.fct.default]p6:
+  //   Except for member functions of class templates, the default arguments 
+  //   in a member function definition that appears outside of the class 
+  //   definition are added to the set of default arguments provided by the 
+  //   member function declaration in the class definition.
   for (unsigned p = 0, NumParams = Old->getNumParams(); p < NumParams; ++p) {
     ParmVarDecl *OldParam = Old->getParamDecl(p);
     ParmVarDecl *NewParam = New->getParamDecl(p);
 
-    if (OldParam->getDefaultArg() && NewParam->getDefaultArg()) {
+    if (OldParam->hasDefaultArg() && NewParam->hasDefaultArg()) {
       Diag(NewParam->getLocation(),
            diag::err_param_default_argument_redefinition)
-        << NewParam->getDefaultArg()->getSourceRange();
-      Diag(OldParam->getLocation(), diag::note_previous_definition);
+        << NewParam->getDefaultArgRange();
+      
+      // Look for the function declaration where the default argument was
+      // actually written, which may be a declaration prior to Old.
+      for (FunctionDecl *Older = Old->getPreviousDeclaration();
+           Older; Older = Older->getPreviousDeclaration()) {
+        if (!Older->getParamDecl(p)->hasDefaultArg())
+          break;
+        
+        OldParam = Older->getParamDecl(p);
+      }        
+      
+      Diag(OldParam->getLocation(), diag::note_previous_definition)
+        << OldParam->getDefaultArgRange();
       Invalid = true;
     } else if (OldParam->getDefaultArg()) {
       // Merge the old default argument into the new parameter
       NewParam->setDefaultArg(OldParam->getDefaultArg());
+    } else if (NewParam->hasDefaultArg()) {
+      if (New->getDescribedFunctionTemplate()) {
+        // Paragraph 4, quoted above, only applies to non-template functions.
+        Diag(NewParam->getLocation(),
+             diag::err_param_default_argument_template_redecl)
+          << NewParam->getDefaultArgRange();
+        Diag(Old->getLocation(), diag::note_template_prev_declaration)
+          << false;
+      } else if (New->getDeclContext()->isDependentContext()) {
+        // C++ [dcl.fct.default]p6 (DR217):
+        //   Default arguments for a member function of a class template shall 
+        //   be specified on the initial declaration of the member function 
+        //   within the class template.
+        //
+        // Reading the tea leaves a bit in DR217 and its reference to DR205 
+        // leads me to the conclusion that one cannot add default function 
+        // arguments for an out-of-line definition of a member function of a 
+        // dependent type.
+        int WhichKind = 2;
+        if (CXXRecordDecl *Record 
+              = dyn_cast<CXXRecordDecl>(New->getDeclContext())) {
+          if (Record->getDescribedClassTemplate())
+            WhichKind = 0;
+          else if (isa<ClassTemplatePartialSpecializationDecl>(Record))
+            WhichKind = 1;
+          else
+            WhichKind = 2;
+        }
+        
+        Diag(NewParam->getLocation(), 
+             diag::err_param_default_argument_member_template_redecl)
+          << WhichKind
+          << NewParam->getDefaultArgRange();
+      }
     }
   }
 
diff --git a/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p10.cpp b/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p10.cpp
new file mode 100644
index 0000000000..82f526745d
--- /dev/null
+++ b/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p10.cpp
@@ -0,0 +1,16 @@
+// RUN: clang-cc -fsyntax-only -verify %s
+
+struct A { 
+  virtual void f(int a = 7);
+}; 
+
+struct B : public A {
+  void f(int a);
+}; 
+
+void m() {
+  B* pb = new B; 
+  A* pa = pb; 
+  pa->f(); // OK, calls pa->B::f(7) 
+  pb->f(); // expected-error{{too few arguments}}
+}
diff --git a/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p2.cpp b/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p2.cpp
new file mode 100644
index 0000000000..143a0caf82
--- /dev/null
+++ b/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p2.cpp
@@ -0,0 +1,9 @@
+// RUN: clang-cc -fsyntax-only -verify %s
+
+void point(int = 3, int = 4);
+
+void test_point() {
+  point(1,2); 
+  point(1); 
+  point();
+}
diff --git a/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p3.cpp b/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p3.cpp
new file mode 100644
index 0000000000..ea16f641db
--- /dev/null
+++ b/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p3.cpp
@@ -0,0 +1,13 @@
+// RUN: clang-cc -fsyntax-only -verify %s
+
+void nondecl(int (*f)(int x = 5)) // {expected-error {{default arguments can only be specified}}}
+{
+  void (*f2)(int = 17)  // {expected-error {{default arguments can only be specified}}}
+  = (void (*)(int = 42))f; // {expected-error {{default arguments can only be specified}}}
+}
+
+struct X0 {
+  int (*f)(int = 17); // expected-error{{default arguments can only be specified for parameters in a function declaration}}
+  
+  void mem8(int (*fp)(int) = (int (*)(int = 17))0); // expected-error{{default arguments can only be specified for parameters in a function declaration}}  
+};
diff --git a/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p4.cpp b/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p4.cpp
new file mode 100644
index 0000000000..bbfaf90939
--- /dev/null
+++ b/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p4.cpp
@@ -0,0 +1,55 @@
+// RUN: clang-cc -fsyntax-only -verify %s
+
+void f0(int i, int j, int k = 3);
+void f0(int i, int j, int k);
+void f0(int i, int j = 2, int k);
+void f0(int i, int j, int k);
+void f0(int i = 1, // expected-note{{previous definition}}
+        int j, int k);
+void f0(int i, int j, int k);
+
+namespace N0 {
+  void f0(int, int, int); // expected-note{{candidate}}
+
+  void test_f0_inner_scope() {
+    f0(); // expected-error{{no matching}}
+  }
+}
+
+void test_f0_outer_scope() {
+  f0(); // okay
+}
+
+void f0(int i = 1, // expected-error{{redefinition of default argument}}
+        int, int); 
+
+template<typename T> void f1(T); // expected-note{{previous}}
+
+template<typename T>
+void f1(T = T()); // expected-error{{cannot be added}}
+
+
+namespace N1 {
+  // example from C++03 standard
+  // FIXME: make these "f2"s into "f"s, then fix our scoping issues
+  void f2(int, int); 
+  void f2(int, int = 7); 
+  void h() {
+    f2(3); // OK, calls f(3, 7) 
+    void f(int = 1, int);	// expected-error{{missing default argument}}
+  }
+  
+  void m()
+  {
+    void f(int, int); // expected-note{{candidate}}
+    f(4);  // expected-error{{no matching}}
+    void f(int, int = 5); // expected-note{{previous definition}}
+    f(4); // okay
+    void f(int, int = 5); // expected-error{{redefinition of default argument}}
+  }
+  
+  void n()
+  {
+    f2(6); // okay
+  }
+}
\ No newline at end of file
diff --git a/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p5.cpp b/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p5.cpp
new file mode 100644
index 0000000000..894c9b5a87
--- /dev/null
+++ b/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p5.cpp
@@ -0,0 +1,18 @@
+// RUN: clang-cc -fsyntax-only -verify %s
+
+float global_f;
+
+void f0(int *ip = &global_f); // expected-error{{incompatible}}
+
+// Example from C++03 standard
+int a = 1; 
+int f(int); 
+int g(int x = f(a));
+
+void h() { 
+  a = 2;
+  {
+    int *a = 0;
+    g(); // FIXME: check that a is called with a value of 2
+  }
+}
diff --git a/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p6.cpp b/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p6.cpp
new file mode 100644
index 0000000000..ef00e7b705
--- /dev/null
+++ b/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p6.cpp
@@ -0,0 +1,32 @@
+// RUN: clang-cc -fsyntax-only -verify %s
+
+class C { 
+  void f(int i = 3); // expected-note{{here}}
+  void g(int i, int j = 99);
+};
+
+void C::f(int i = 3) { } // expected-error{{redefinition of default argument}}
+
+void C::g(int i = 88, int j) { }
+
+void test_C(C c) {
+  c.f();
+  c.g();
+}
+
+template<typename T>
+struct X0 {
+  void f(int);
+  
+  struct Inner {
+    void g(int);
+  };
+};
+
+// DR217
+template<typename T>
+void X0<T>::f(int = 17) { } // expected-error{{cannot be added}}
+
+// DR217 + DR205 (reading tea leaves)
+template<typename T>
+void X0<T>::Inner::g(int = 17) { } // expected-error{{cannot be added}}
diff --git a/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p7.cpp b/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p7.cpp
new file mode 100644
index 0000000000..9c1d3a91c9
--- /dev/null
+++ b/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p7.cpp
@@ -0,0 +1,7 @@
+// RUN: clang-cc -fsyntax-only -verify %s
+
+void h()
+{
+  int i;
+  extern void h2(int x = sizeof(i)); // expected-error {{default argument references local variable 'i' of enclosing function}}
+}
diff --git a/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p8.cpp b/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p8.cpp
new file mode 100644
index 0000000000..574237ee55
--- /dev/null
+++ b/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p8.cpp
@@ -0,0 +1,4 @@
+// RUN: clang-cc -fsyntax-only -verify %s
+class A { 
+  void f(A* p = this) { }	// expected-error{{invalid use of 'this'}}
+};
diff --git a/test/SemaCXX/default2.cpp b/test/SemaCXX/default2.cpp
index dc83ac489f..183452070d 100644
--- a/test/SemaCXX/default2.cpp
+++ b/test/SemaCXX/default2.cpp
@@ -24,20 +24,8 @@ int f1(int i, int i, int j) { // expected-error {{redefinition of parameter 'i'}
 int x;
 void g(int x, int y = x); // expected-error {{default argument references parameter 'x'}}
 
-void h()
-{
-   int i;
-   extern void h2(int x = sizeof(i)); // expected-error {{default argument references local variable 'i' of enclosing function}}
-}
-
 void g2(int x, int y, int z = x + y); // expected-error {{default argument references parameter 'x'}} expected-error {{default argument references parameter 'y'}}
 
-void nondecl(int (*f)(int x = 5)) // {expected-error {{default arguments can only be specified}}}
-{
-  void (*f2)(int = 17)  // {expected-error {{default arguments can only be specified}}}
-    = (void (*)(int = 42))f; // {expected-error {{default arguments can only be specified}}}
-}
-
 class X {
   void f(X* x = this); // expected-error{{invalid use of 'this' outside of a nonstatic member function}}
 
@@ -82,10 +70,6 @@ struct Y {
   };
 
   static int b; 
-
-  int (*f)(int = 17); // expected-error{{default arguments can only be specified for parameters in a function declaration}}
-
-  void mem8(int (*fp)(int) = (int (*)(int = 17))0); // expected-error{{default arguments can only be specified for parameters in a function declaration}}
 }; 
 
 int Y::mem3(int i = b) { return i; } // OK; use X::b
diff --git a/test/SemaTemplate/default-expr-arguments.cpp b/test/SemaTemplate/default-expr-arguments.cpp
index d689cc86e6..01d0e60887 100644
--- a/test/SemaTemplate/default-expr-arguments.cpp
+++ b/test/SemaTemplate/default-expr-arguments.cpp
@@ -45,5 +45,26 @@ template<typename T> struct G {
 
 void s(G<int> flags = 10) { }
 
+// Test default arguments
+template<typename T>
+struct X0 {
+  void f(T = T()); // expected-error{{no matching}}
+};
+
+template<typename U>
+void X0<U>::f(U) { }
+
+void test_x0(X0<int> xi) {
+  xi.f();
+  xi.f(17);
+}
 
+struct NotDefaultConstructible { // expected-note{{candidate}}
+  NotDefaultConstructible(int); // expected-note{{candidate}}
+};
 
+void test_x0_not_default_constructible(X0<NotDefaultConstructible> xn) {
+  xn.f(NotDefaultConstructible(17));
+  xn.f(42);
+  xn.f(); // expected-note{{in instantiation of default function argument}}
+}