[PATCH] D94719: [clangd] Make ExpandAutoType not available on template params.

[Adam Czachorowski via Phabricator via cfe-commits]

adamcz created this revision.
adamcz added a reviewer: hokein.
Herald added subscribers: usaxena95, kadircet, arphaman.
adamcz requested review of this revision.
Herald added subscribers: cfe-commits, MaskRay, ilya-biryukov.
Herald added a project: clang.

We cannot expand auto when used inside a template param (C++17 feature),
so do not offer it there.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D94719

Files:
  clang-tools-extra/clangd/refactor/tweaks/ExpandAutoType.cpp
  clang-tools-extra/clangd/unittests/tweaks/ExpandAutoTypeTests.cpp


Index: clang-tools-extra/clangd/unittests/tweaks/ExpandAutoTypeTests.cpp
===================================================================
--- clang-tools-extra/clangd/unittests/tweaks/ExpandAutoTypeTests.cpp
+++ clang-tools-extra/clangd/unittests/tweaks/ExpandAutoTypeTests.cpp
@@ -80,6 +80,9 @@
   // unknown types in a template should not be replaced
   EXPECT_THAT(apply("template <typename T> void x() { ^auto y = T::z(); }"),
               StartsWith("fail: Could not deduce type for 'auto' type"));
+
+  ExtraArgs.push_back("-std=c++17");
+  EXPECT_UNAVAILABLE("template <au^to X> class Y;");
 }
 
 } // namespace
Index: clang-tools-extra/clangd/refactor/tweaks/ExpandAutoType.cpp
===================================================================
--- clang-tools-extra/clangd/refactor/tweaks/ExpandAutoType.cpp
+++ clang-tools-extra/clangd/refactor/tweaks/ExpandAutoType.cpp
@@ -82,6 +82,15 @@
   return false;
 }
 
+// Returns true iff "auto" in Node is really part of the template parameter,
+// which we cannot expand.
+bool isTemplateParam(const SelectionTree::Node *Node) {
+  if (Node->Parent)
+    if (Node->Parent->ASTNode.get<NonTypeTemplateParmDecl>())
+      return true;
+  return false;
+}
+
 bool ExpandAutoType::prepare(const Selection& Inputs) {
   CachedLocation = llvm::None;
   if (auto *Node = Inputs.ASTSelection.commonAncestor()) {
@@ -90,7 +99,8 @@
         // Code in apply() does handle 'decltype(auto)' yet.
         if (!Result.getTypePtr()->isDecltypeAuto() &&
             !isStructuredBindingType(Node) &&
-            !isDeducedAsLambda(Node, Result.getBeginLoc()))
+            !isDeducedAsLambda(Node, Result.getBeginLoc()) &&
+            !isTemplateParam(Node))
           CachedLocation = Result;
       }
     }


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