Implement support for out-of-line definitions of the class members of class

templates, e.g.,

  template<typename T>
  struct Outer {
    struct Inner;
  };

  template<typename T>
  struct Outer<T>::Inner {
    // ...
  };

Implementing this feature required some extensions to ActOnTag, which
now takes a set of template parameter lists, and is the precursor to
removing the ActOnClassTemplate function from the parser Action
interface. The reason for this approach is simple: the parser cannot
tell the difference between a class template definition and the
definition of a member of a class template; both have template
parameter lists, and semantic analysis determines what that template
parameter list means.

There is still some cleanup to do with ActOnTag and
ActOnClassTemplate. This commit provides the basic functionality we
need, however.

llvm-svn: 76820

10 files changed, 93 insertions, 29 deletions

diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index df62573e8cd..76d069fd8a2 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -733,10 +733,11 @@ def note_template_param_prev_default_arg : Note<
   "previous default template argument defined here">;
 def err_template_param_default_arg_missing : Error<
   "template parameter missing a default argument">;
-
+  
 def err_template_variable : Error<"variable %0 declared as a template">;
 def err_template_variable_noparams : Error<
   "extraneous 'template<>' in declaration of variable %0">;
+
 // C++ Template Argument Lists
 def err_template_arg_list_different_arity : Error<
   "%select{too few|too many}0 template arguments for "
diff --git a/clang/include/clang/Parse/Action.h b/clang/include/clang/Parse/Action.h
index 23c5428ef68..92f38ede895 100644
--- a/clang/include/clang/Parse/Action.h
+++ b/clang/include/clang/Parse/Action.h
@@ -422,6 +422,18 @@ public:
                              bool &OwnedDecl) {
     // TagType is an instance of DeclSpec::TST, indicating what kind of tag this
     // is (struct/union/enum/class).
+    return ActOnTag(S, TagSpec, TK, KWLoc, SS, Name, NameLoc, Attr, AS,
+                    MultiTemplateParamsArg(*this, 0, 0), OwnedDecl);
+  }
+
+  virtual DeclPtrTy ActOnTag(Scope *S, unsigned TagSpec, TagKind TK,
+                             SourceLocation KWLoc, const CXXScopeSpec &SS,
+                             IdentifierInfo *Name, SourceLocation NameLoc,
+                             AttributeList *Attr, AccessSpecifier AS,
+                             MultiTemplateParamsArg TemplateParameterLists,
+                             bool &OwnedDecl) {
+    // TagType is an instance of DeclSpec::TST, indicating what kind of tag this
+    // is (struct/union/enum/class).
     return DeclPtrTy();
   }
   
diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
index 930d58dd262..f28ffe35094 100644
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -673,15 +673,6 @@ void Parser::ParseClassSpecifier(tok::TokenKind TagTokKind,
                                  TemplateParams? TemplateParams->size() : 0));
     }
     TemplateId->Destroy();
-  } else if (TemplateParams && TK != Action::TK_Reference) {
-    // Class template declaration or definition.
-    TagOrTempResult = Actions.ActOnClassTemplate(CurScope, TagType, TK, 
-                                                 StartLoc, SS, Name, NameLoc, 
-                                                 Attr,
-                       Action::MultiTemplateParamsArg(Actions, 
-                                                      &(*TemplateParams)[0],
-                                                      TemplateParams->size()),
-                                                 AS);
   } else if (TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation &&
              TK == Action::TK_Declaration) {
     // Explicit instantiation of a member of a class template
@@ -702,7 +693,11 @@ void Parser::ParseClassSpecifier(tok::TokenKind TagTokKind,
 
     // Declaration or definition of a class type
     TagOrTempResult = Actions.ActOnTag(CurScope, TagType, TK, StartLoc, SS, 
-                                       Name, NameLoc, Attr, AS, Owned);
+                                       Name, NameLoc, Attr, AS,
+                                  Action::MultiTemplateParamsArg(Actions, 
+                                    TemplateParams? &(*TemplateParams)[0] : 0,
+                                    TemplateParams? TemplateParams->size() : 0),
+                                       Owned);
   }
 
   // Parse the optional base clause (C++ only).
diff --git a/clang/lib/Parse/ParseTemplate.cpp b/clang/lib/Parse/ParseTemplate.cpp
index 57a09fbc737..df7c22cf265 100644
--- a/clang/lib/Parse/ParseTemplate.cpp
+++ b/clang/lib/Parse/ParseTemplate.cpp
@@ -96,9 +96,15 @@ Parser::ParseTemplateDeclarationOrSpecialization(unsigned Context,
     // Parse the '<' template-parameter-list '>'
     SourceLocation LAngleLoc, RAngleLoc;
     TemplateParameterList TemplateParams;
-    ParseTemplateParameters(ParamLists.size(), TemplateParams, LAngleLoc, 
-                            RAngleLoc);
-
+    if (ParseTemplateParameters(ParamLists.size(), TemplateParams, LAngleLoc, 
+                                RAngleLoc)) {
+      // Skip until the semi-colon or a }.
+      SkipUntil(tok::r_brace, true, true);
+      if (Tok.is(tok::semi))
+        ConsumeToken();
+      return DeclPtrTy();      
+    }
+      
     if (!TemplateParams.empty())
       isSpecialiation = false;
 
@@ -219,6 +225,8 @@ Parser::ParseSingleDeclarationAfterTemplate(
 /// The template parameter we parse will be added to this list. LAngleLoc and
 /// RAngleLoc will receive the positions of the '<' and '>', respectively, 
 /// that enclose this template parameter list.
+///
+/// \returns true if an error occurred, false otherwise.
 bool Parser::ParseTemplateParameters(unsigned Depth,
                                      TemplateParameterList &TemplateParams,
                                      SourceLocation &LAngleLoc,
@@ -226,7 +234,7 @@ bool Parser::ParseTemplateParameters(unsigned Depth,
   // Get the template parameter list.
   if(!Tok.is(tok::less)) {
     Diag(Tok.getLocation(), diag::err_expected_less_after) << "template";
-    return false;
+    return true;
   }
   LAngleLoc = ConsumeToken();
   
@@ -236,11 +244,11 @@ bool Parser::ParseTemplateParameters(unsigned Depth,
   else if(ParseTemplateParameterList(Depth, TemplateParams)) {
     if(!Tok.is(tok::greater)) {
       Diag(Tok.getLocation(), diag::err_expected_greater);
-      return false;
+      return true;
     }
     RAngleLoc = ConsumeToken();
   }
-  return true;
+  return false;
 }
 
 /// ParseTemplateParameterList - Parse a template parameter list. If
@@ -392,8 +400,8 @@ Parser::ParseTemplateTemplateParameter(unsigned Depth, unsigned Position) {
   SourceLocation LAngleLoc, RAngleLoc;
   {
     ParseScope TemplateParmScope(this, Scope::TemplateParamScope);
-    if(!ParseTemplateParameters(Depth + 1, TemplateParams, LAngleLoc,
-                                RAngleLoc)) {
+    if(ParseTemplateParameters(Depth + 1, TemplateParams, LAngleLoc,
+                               RAngleLoc)) {
       return DeclPtrTy();
     }
   }
diff --git a/clang/lib/Sema/Sema.h b/clang/lib/Sema/Sema.h
index 7daf3f90a86..78d64b53c09 100644
--- a/clang/lib/Sema/Sema.h
+++ b/clang/lib/Sema/Sema.h
@@ -522,6 +522,7 @@ public:
                              SourceLocation KWLoc, const CXXScopeSpec &SS,
                              IdentifierInfo *Name, SourceLocation NameLoc,
                              AttributeList *Attr, AccessSpecifier AS,
+                             MultiTemplateParamsArg TemplateParameterLists,
                              bool &OwnedDecl);
   
   virtual void ActOnDefs(Scope *S, DeclPtrTy TagD, SourceLocation DeclStart,
diff --git a/clang/lib/Sema/SemaCXXScopeSpec.cpp b/clang/lib/Sema/SemaCXXScopeSpec.cpp
index cf73725e7f3..be1a1103b3d 100644
--- a/clang/lib/Sema/SemaCXXScopeSpec.cpp
+++ b/clang/lib/Sema/SemaCXXScopeSpec.cpp
@@ -213,7 +213,7 @@ bool Sema::RequireCompleteDeclContext(const CXXScopeSpec &SS) {
   if (!SS.isSet() || SS.isInvalid())
     return false;
   
-  DeclContext *DC = computeDeclContext(SS);
+  DeclContext *DC = computeDeclContext(SS, true);
   if (TagDecl *Tag = dyn_cast<TagDecl>(DC)) {
     // If we're currently defining this type, then lookup into the
     // type is okay: don't complain that it isn't complete yet.
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 2e280f58cb5..d9c1224b435 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -1866,14 +1866,14 @@ Sema::ActOnVariableDeclarator(Scope* S, Declarator& D, DeclContext* DC,
     } else {
       // There is an extraneous 'template<>' for this variable. Complain
       // about it, but allow the declaration of the variable.
-      Diag(TemplateParams->getTemplateLoc(), diag::err_template_variable)
+      Diag(TemplateParams->getTemplateLoc(), 
+           diag::err_template_variable_noparams)
         << II
         << SourceRange(TemplateParams->getTemplateLoc(),
                        TemplateParams->getRAngleLoc());          
     }
   }        
   
-  // The variable can not 
   NewVD = VarDecl::Create(Context, DC, D.getIdentifierLoc(), 
                           II, R, SC, 
                           // FIXME: Move to DeclGroup...
@@ -3522,6 +3522,7 @@ Sema::DeclPtrTy Sema::ActOnTag(Scope *S, unsigned TagSpec, TagKind TK,
                                SourceLocation KWLoc, const CXXScopeSpec &SS,
                                IdentifierInfo *Name, SourceLocation NameLoc,
                                AttributeList *Attr, AccessSpecifier AS,
+                               MultiTemplateParamsArg TemplateParameterLists,
                                bool &OwnedDecl) {
   // If this is not a definition, it must have a name.
   assert((Name != 0 || TK == TK_Definition) &&
@@ -3537,6 +3538,28 @@ Sema::DeclPtrTy Sema::ActOnTag(Scope *S, unsigned TagSpec, TagKind TK,
   case DeclSpec::TST_enum:   Kind = TagDecl::TK_enum; break;
   }
   
+  if (TK != TK_Reference) {
+    if (TemplateParameterList *TemplateParams
+          = MatchTemplateParametersToScopeSpecifier(KWLoc, SS,
+                        (TemplateParameterList**)TemplateParameterLists.get(),
+                                              TemplateParameterLists.size())) {
+      if (TemplateParams->size() > 0) {
+        // This is a declaration or definition of a class template (which may
+        // be a member of another template).
+        OwnedDecl = false;
+        DeclResult Result = ActOnClassTemplate(S, TagSpec, TK, KWLoc,
+                                               SS, Name, NameLoc, Attr,
+                                               move(TemplateParameterLists),
+                                               AS);
+        return Result.get();
+      } else {
+        // FIXME: diagnose the extraneous 'template<>', once we recover
+        // slightly better in ParseTemplate.cpp from bogus template
+        // parameters.
+      }
+    }        
+  }  
+  
   DeclContext *SearchDC = CurContext;
   DeclContext *DC = CurContext;
   NamedDecl *PrevDecl = 0;
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 5f772bc22c0..981b8508c56 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -2895,7 +2895,8 @@ Sema::ActOnExplicitInstantiation(Scope *S, SourceLocation TemplateLoc,
 
   bool Owned = false;
   DeclPtrTy TagD = ActOnTag(S, TagSpec, Action::TK_Reference,
-                            KWLoc, SS, Name, NameLoc, Attr, AS_none, Owned);
+                            KWLoc, SS, Name, NameLoc, Attr, AS_none,
+                            MultiTemplateParamsArg(*this, 0, 0), Owned);
   if (!TagD)
     return true;
 
diff --git a/clang/test/CXX/temp/temp.decls/temp.class/temp.mem.class/p1.cpp b/clang/test/CXX/temp/temp.decls/temp.class/temp.mem.class/p1.cpp
new file mode 100644
index 00000000000..9bafacc00a7
--- /dev/null
+++ b/clang/test/CXX/temp/temp.decls/temp.class/temp.mem.class/p1.cpp
@@ -0,0 +1,27 @@
+// RUN: clang-cc -fsyntax-only -verify %s
+
+template<typename T, typename U>
+struct X0 {
+  struct Inner;
+};
+
+template<typename T, typename U>
+struct X0<T, U>::Inner {
+  T x;
+  U y;
+  
+  void f() { x = y; } // expected-error{{incompatible}}
+};
+
+
+void test(int i, float f) {
+  X0<int, float>::Inner inner;
+  inner.x = 5;
+  inner.y = 3.4;
+  inner.f();
+  
+  X0<int*, float *>::Inner inner2;
+  inner2.x = &i;
+  inner2.y = &f;
+  inner2.f(); // expected-note{{instantiation}}
+}
\ No newline at end of file
diff --git a/clang/test/Parser/cxx-template-decl.cpp b/clang/test/Parser/cxx-template-decl.cpp
index b7117cd8d62..5f49fb15d7c 100644
--- a/clang/test/Parser/cxx-template-decl.cpp
+++ b/clang/test/Parser/cxx-template-decl.cpp
@@ -3,12 +3,8 @@
 // Errors
 export class foo { };   // expected-error {{expected template}}
 template  x;            // expected-error {{C++ requires a type specifier for all declarations}}
-export template x;      // expected-error {{expected '<' after 'template'}} \
-                        // expected-note {{exported templates are unsupported}} \
-// expected-error {{C++ requires a type specifier for all declarations}} \
-// expected-error {{declared as a template}}
-// See Sema::ParsedFreeStandingDeclSpec about the double diagnostic. This is
-// because ParseNonTypeTemplateParameter starts parsing a DeclSpec.
+export template x;      // expected-error {{expected '<' after 'template'}}
+export template<class T> class x0; // expected-note {{exported templates are unsupported}}
 template < ;            // expected-error {{parse error}} expected-error {{declaration does not declare anything}}
 template <template X> struct Err1; // expected-error {{expected '<' after 'template'}}
 template <template <typename> > struct Err2;       // expected-error {{expected 'class' before '>'}}