C++ modules: if a class is defined in multiple modules (for instance, because

it is an implicit instantiation of a class template specialization), pick the
first-loaded definition to be the canonical definition, and merge all other
definitions into it.

This is still rather incomplete -- we need to extend every form of declaration
that can appear within a CXXRecordDecl to be redeclarable if it came from an
AST file (this includes fields, enumerators, ...).

llvm-svn: 190315

7 files changed, 33 insertions, 0 deletions

diff --git a/clang/test/Modules/Inputs/cxx-templates-a.h b/clang/test/Modules/Inputs/cxx-templates-a.h
index dbf12dacbae..37e3426fc0b 100644
--- a/clang/test/Modules/Inputs/cxx-templates-a.h
+++ b/clang/test/Modules/Inputs/cxx-templates-a.h
@@ -24,3 +24,9 @@ template<typename T> void PerformDelayedLookup(T &t) {
 template<typename T> void PerformDelayedLookupInDefaultArgument(T &t, int a = (FoundByADL(T()), 0)) {}
 
 template<typename T> struct RedeclaredAsFriend {};
+
+void use_some_template_a() {
+  SomeTemplate<char[2]> a;
+  SomeTemplate<char[1]> b, c;
+  b = c;
+}
diff --git a/clang/test/Modules/Inputs/cxx-templates-b.h b/clang/test/Modules/Inputs/cxx-templates-b.h
index 9bc76d5bbae..c495074a93f 100644
--- a/clang/test/Modules/Inputs/cxx-templates-b.h
+++ b/clang/test/Modules/Inputs/cxx-templates-b.h
@@ -35,6 +35,12 @@ struct RedeclareTemplateAsFriend {
   friend struct RedeclaredAsFriend;
 };
 
+void use_some_template_b() {
+  SomeTemplate<char[1]> a;
+  SomeTemplate<char[2]> b, c;
+  b = c;
+}
+
 @import cxx_templates_a;
 template<typename T> void UseDefinedInBImplIndirectly(T &v) {
   PerformDelayedLookup(v);
diff --git a/clang/test/Modules/Inputs/templates-left.h b/clang/test/Modules/Inputs/templates-left.h
index 7451420c748..7c9be8c6514 100644
--- a/clang/test/Modules/Inputs/templates-left.h
+++ b/clang/test/Modules/Inputs/templates-left.h
@@ -27,3 +27,5 @@ void triggerPendingInstantiation() {
 }
 
 void redeclDefinitionEmit(){}
+
+typedef Outer<int>::Inner OuterIntInner_left;
diff --git a/clang/test/Modules/Inputs/templates-right.h b/clang/test/Modules/Inputs/templates-right.h
index d3524d34769..bacaa49b60c 100644
--- a/clang/test/Modules/Inputs/templates-right.h
+++ b/clang/test/Modules/Inputs/templates-right.h
@@ -25,3 +25,5 @@ void triggerPendingInstantiationToo() {
 }
 
 void redeclDefinitionEmit(){}
+
+typedef Outer<int>::Inner OuterIntInner_right;
diff --git a/clang/test/Modules/Inputs/templates-top.h b/clang/test/Modules/Inputs/templates-top.h
index 5985ee8820d..b5d0b6bda13 100644
--- a/clang/test/Modules/Inputs/templates-top.h
+++ b/clang/test/Modules/Inputs/templates-top.h
@@ -15,3 +15,7 @@ template <typename T> class A::WhereAmI {
 public:
   static void func() {}
 };
+
+template<typename T> struct Outer {
+  struct Inner {};
+};
diff --git a/clang/test/Modules/cxx-templates.cpp b/clang/test/Modules/cxx-templates.cpp
index 9e6cd17828e..f34a2bdaa71 100644
--- a/clang/test/Modules/cxx-templates.cpp
+++ b/clang/test/Modules/cxx-templates.cpp
@@ -82,6 +82,14 @@ typedef SomeTemplate<int&> SomeTemplateIntRef;
 SomeTemplate<char*> some_template_char_ptr;
 SomeTemplate<char&> some_template_char_ref;
 
+void testImplicitSpecialMembers(SomeTemplate<char[1]> &a,
+                                const SomeTemplate<char[1]> &b,
+                                SomeTemplate<char[2]> &c,
+                                const SomeTemplate<char[2]> &d) {
+  a = b;
+  c = d;
+}
+
 // CHECK-GLOBAL:      DeclarationName 'f'
 // CHECK-GLOBAL-NEXT: |-FunctionTemplate {{.*}} 'f'
 // CHECK-GLOBAL-NEXT: `-FunctionTemplate {{.*}} 'f'
diff --git a/clang/test/Modules/templates.mm b/clang/test/Modules/templates.mm
index 1fef967e400..08b216646c3 100644
--- a/clang/test/Modules/templates.mm
+++ b/clang/test/Modules/templates.mm
@@ -32,5 +32,10 @@ void testRedeclDefinition() {
   redeclDefinitionEmit();
 }
 
+// These three are all the same type.
+typedef OuterIntInner_left OuterIntInner;
+typedef OuterIntInner_right OuterIntInner;
+typedef Outer<int>::Inner OuterIntInner;
+
 // CHECK: call {{.*pendingInstantiation}}
 // CHECK: call {{.*redeclDefinitionEmit}}