[index] Avoid a crash that happens when looking up a dependent name

in a record that has no definition

rdar://32194921

llvm-svn: 303045

3 files changed, 15 insertions, 0 deletions

diff --git a/clang/lib/Index/IndexBody.cpp b/clang/lib/Index/IndexBody.cpp
index 9439c11dac0..08d233fb83e 100644
--- a/clang/lib/Index/IndexBody.cpp
+++ b/clang/lib/Index/IndexBody.cpp
@@ -165,6 +165,9 @@ public:
     if (!TD)
       return true;
     CXXRecordDecl *RD = TD->getTemplatedDecl();
+    if (!RD->hasDefinition())
+      return true;
+    RD = RD->getDefinition();
     std::vector<const NamedDecl *> Symbols =
         RD->lookupDependentName(NameInfo.getName(), Filter);
     // FIXME: Improve overload handling.
diff --git a/clang/lib/Index/IndexTypeSourceInfo.cpp b/clang/lib/Index/IndexTypeSourceInfo.cpp
index 7e2041c6cb0..e9ca651e002 100644
--- a/clang/lib/Index/IndexTypeSourceInfo.cpp
+++ b/clang/lib/Index/IndexTypeSourceInfo.cpp
@@ -157,6 +157,9 @@ public:
     if (!TD)
       return true;
     CXXRecordDecl *RD = TD->getTemplatedDecl();
+    if (!RD->hasDefinition())
+      return true;
+    RD = RD->getDefinition();
     DeclarationName Name(DNT->getIdentifier());
     std::vector<const NamedDecl *> Symbols = RD->lookupDependentName(
         Name, [](const NamedDecl *ND) { return isa<TypeDecl>(ND); });
diff --git a/clang/test/Index/Core/index-dependent-source.cpp b/clang/test/Index/Core/index-dependent-source.cpp
index 35f5cf45c35..25410799a86 100644
--- a/clang/test/Index/Core/index-dependent-source.cpp
+++ b/clang/test/Index/Core/index-dependent-source.cpp
@@ -122,3 +122,12 @@ void indexDependentOverloads(const TemplateClass<T, S> &object) {
   object.overload1(Y());
 // CHECK-NOT: [[@LINE-1]]
 }
+
+template<typename T> struct UndefinedTemplateClass;
+
+template<typename T>
+void undefinedTemplateLookup(UndefinedTemplateClass<T> &x) {
+// Shouldn't crash!
+  x.lookup;
+  typename UndefinedTemplateClass<T>::Type y;
+}