From 117b9230a74cfbfe5e409adc2aa2d33c9c584a81 Mon Sep 17 00:00:00 2001
From: Kadir Cetinkaya <kadircet@google.com>
Date: Sat, 27 Jun 2020 11:12:51 +0200
Subject: [PATCH] [clangd][Hover] Dont crash on null types

Reviewers: hokein, sammccall

Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, usaxena95, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D82701
---
 clang-tools-extra/clangd/Hover.cpp                | 14 +++-----------
 clang-tools-extra/clangd/unittests/HoverTests.cpp | 11 +++++++++++
 2 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/clang-tools-extra/clangd/Hover.cpp b/clang-tools-extra/clangd/Hover.cpp
index 3d5d002..bd5b711 100644
--- a/clang-tools-extra/clangd/Hover.cpp
+++ b/clang-tools-extra/clangd/Hover.cpp
@@ -124,8 +124,8 @@ std::string printType(QualType QT, const PrintingPolicy &Policy) {
   // TypePrinter doesn't resolve decltypes, so resolve them here.
   // FIXME: This doesn't handle composite types that contain a decltype in them.
   // We should rather have a printing policy for that.
-  while (const auto *DT = QT->getAs<DecltypeType>())
-    QT = DT->getUnderlyingType();
+  while (!QT.isNull() && QT->isDecltypeType())
+    QT = QT->getAs<DecltypeType>()->getUnderlyingType();
   return QT.getAsString(Policy);
 }
 
@@ -297,15 +297,7 @@ void fillFunctionTypeAndParams(HoverInfo &HI, const Decl *D,
   for (const ParmVarDecl *PVD : FD->parameters()) {
     HI.Parameters->emplace_back();
     auto &P = HI.Parameters->back();
-    if (!PVD->getType().isNull()) {
-      P.Type = printType(PVD->getType(), Policy);
-    } else {
-      std::string Param;
-      llvm::raw_string_ostream OS(Param);
-      PVD->dump(OS);
-      OS.flush();
-      elog("Got param with null type: {0}", Param);
-    }
+    P.Type = printType(PVD->getType(), Policy);
     if (!PVD->getName().empty())
       P.Name = PVD->getNameAsString();
     if (const Expr *DefArg = getDefaultArg(PVD)) {
diff --git a/clang-tools-extra/clangd/unittests/HoverTests.cpp b/clang-tools-extra/clangd/unittests/HoverTests.cpp
index c6c0daa..78964ee 100644
--- a/clang-tools-extra/clangd/unittests/HoverTests.cpp
+++ b/clang-tools-extra/clangd/unittests/HoverTests.cpp
@@ -708,6 +708,17 @@ class Foo {})cpp";
          HI.Definition = "X x";
          HI.Type = "struct X";
        }},
+      {// Don't crash on null types.
+       R"cpp(auto [^[[x]]] = 1; /*error-ok*/)cpp",
+       [](HoverInfo &HI) {
+         HI.Name = "x";
+         HI.Kind = index::SymbolKind::Variable;
+         HI.NamespaceScope = "";
+         HI.Definition = "";
+         HI.Type = "NULL TYPE";
+         // Bindings are in theory public members of an anonymous struct.
+         HI.AccessSpecifier = "public";
+       }},
   };
   for (const auto &Case : Cases) {
     SCOPED_TRACE(Case.Code);
-- 
2.7.4