[PATCH] D142440: [clangd] Don't show 'auto' type hint when type deduction fails

[Nathan Ridge via Phabricator via cfe-commits]

nridge created this revision.
nridge added reviewers: sammccall, kadircet.
Herald added a subscriber: arphaman.
Herald added a project: All.
nridge requested review of this revision.
Herald added subscribers: cfe-commits, MaskRay, ilya-biryukov.
Herald added a project: clang-tools-extra.

Fixes https://github.com/clangd/clangd/issues/1475


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D142440

Files:
  clang-tools-extra/clangd/InlayHints.cpp
  clang-tools-extra/clangd/unittests/InlayHintTests.cpp


Index: clang-tools-extra/clangd/unittests/InlayHintTests.cpp
===================================================================
--- clang-tools-extra/clangd/unittests/InlayHintTests.cpp
+++ clang-tools-extra/clangd/unittests/InlayHintTests.cpp
@@ -1256,6 +1256,13 @@
   )cpp");
 }
 
+TEST(TypeHints, InvalidType) {
+  assertTypeHints(R"cpp(
+    auto x = (unknown_type)42; /*error-ok*/
+    auto *y = (unknown_ptr)nullptr;
+  )cpp");
+}
+
 TEST(TypeHints, ReturnTypeDeduction) {
   assertTypeHints(
       R"cpp(
Index: clang-tools-extra/clangd/InlayHints.cpp
===================================================================
--- clang-tools-extra/clangd/InlayHints.cpp
+++ clang-tools-extra/clangd/InlayHints.cpp
@@ -303,8 +303,8 @@
       return true;
     }
 
-    if (D->getType()->getContainedAutoType()) {
-      if (!D->getType()->isDependentType()) {
+    if (auto *AT = D->getType()->getContainedAutoType()) {
+      if (!AT->getDeducedType().isNull() && !D->getType()->isDependentType()) {
         // Our current approach is to place the hint on the variable
         // and accordingly print the full type
         // (e.g. for `const auto& x = 42`, print `const int&`).


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