[CodeComplete] [clangd] Fix crash on ValueDecl with a null type

[kadircet]

LGTM

clang-tools-extra/unittests/clangd/CodeCompleteTests.cpp

2322

nit: WorksWithNullType ? it doesn't seem like crashing

[ilya-biryukov]

• Rename the test
• clang-format

[ilya-biryukov]

clang-tools-extra/unittests/clangd/CodeCompleteTests.cpp

2322

Indeed, I've been using this naming convention for ages, but I can see why it might be confusing.

clang-tools-extra/clangd/ExpectedTypes.cpp

static const Type *toEquivClass(ASTContext &Ctx, QualType T) {
   // FIXME: also drop qualifiers from pointer types, e.g. 'const T* => T*'
   return T.getTypePtr();
 }
 
 static llvm::Optional<QualType>
 typeOfCompletion(const CodeCompletionResult &R) {
   auto *VD = dyn_cast_or_null<ValueDecl>(R.Declaration);
   if (!VD)
-    return None; // We handle only variables and functions below.
+    return llvm::None; // We handle only variables and functions below.
   auto T = VD->getType();
+  if (T.isNull())
+    return llvm::None;
   if (auto FuncT = T->getAs<FunctionType>()) {
     // Functions are a special case. They are completed as 'foo()' and we want
     // to match their return type rather than the function type itself.
     // FIXME(ibiryukov): in some cases, we might want to avoid completing `()`
     // after the function name, e.g. `std::cout << std::endl`.
     return FuncT->getReturnType();
   }
   return T;

clang-tools-extra/unittests/clangd/CodeCompleteTests.cpp

TEST(CompletionTest, ObjectiveCMethodTwoArgumentsFromMiddle) {
   auto C = Results.Completions;
   EXPECT_THAT(C, ElementsAre(Named("fooey:")));
   EXPECT_THAT(C, ElementsAre(Kind(CompletionItemKind::Method)));
   EXPECT_THAT(C, ElementsAre(ReturnType("id")));
   EXPECT_THAT(C, ElementsAre(Signature("(unsigned int)")));
   EXPECT_THAT(C, ElementsAre(SnippetSuffix("${1:(unsigned int)}")));
 }
 
+TEST(CompletionTest, CrashOnNullType) {
+  auto Results = completions(R"cpp(
+    int main() {
+      for (auto [loopVar] : y ) { // y has to be unresolved.
+        int z = loopV^;
+      }
+    }
+  )cpp").Completions;
+  EXPECT_THAT(Results, ElementsAre(Named("loopVar")));
+}
+
 } // namespace
 } // namespace clangd
 } // namespace clang

clang/lib/Sema/SemaCodeComplete.cpp

QualType clang::getDeclUsageType(ASTContext &C, const NamedDecl *ND) {
   else if (const auto *Method = dyn_cast<ObjCMethodDecl>(ND))
     T = Method->getSendResultType();
   else if (const auto *Enumerator = dyn_cast<EnumConstantDecl>(ND))
     T = C.getTypeDeclType(cast<EnumDecl>(Enumerator->getDeclContext()));
   else if (const auto *Property = dyn_cast<ObjCPropertyDecl>(ND))
     T = Property->getType();
   else if (const auto *Value = dyn_cast<ValueDecl>(ND))
     T = Value->getType();
-  else
+
+  if (T.isNull())
     return QualType();
 
   // Dig through references, function pointers, and block pointers to
   // get down to the likely type of an expression when the entity is
   // used.
   do {
     if (const auto *Ref = T->getAs<ReferenceType>()) {
       T = Ref->getPointeeType();

clang/test/CodeCompletion/crash-null-type.cpp

+void test() {
+  for (auto [loopVar] : y) { // y has to be unresolved
+    loopVa
+  }
+}
+// RUN: not %clang_cc1 -fsyntax-only -code-completion-at=%s:3:11 %s -o - \
+// RUN:            | FileCheck %s
+// CHECK: COMPLETION: loopVar