[clangd] Move the selection decltype hack to getSourceRange.

Previously, it was in canSafelySkipNode, which is only used to decide
whether we should descend into it and its children, and we still used
the incomplete Decltypeloc.getSourceRange() to claim tokens, which will
cause some tokens were not claimed correctly.

Separate a change of https://reviews.llvm.org/D116536

Reviewed By: sammccall

Differential Revision: https://reviews.llvm.org/D116586

2 files changed, 16 insertions, 11 deletions

diff --git a/clang-tools-extra/clangd/Selection.cpp b/clang-tools-extra/clangd/Selection.cpp
index 2024228e2b58..40021c62d9e2 100644
--- a/clang-tools-extra/clangd/Selection.cpp
+++ b/clang-tools-extra/clangd/Selection.cpp
@@ -60,6 +60,21 @@ void recordMetrics(const SelectionTree &S, const LangOptions &Lang) {
 
 // Return the range covering a node and all its children.
 SourceRange getSourceRange(const DynTypedNode &N) {
+  // DeclTypeTypeLoc::getSourceRange() is incomplete, which would lead to
+  // failing to descend into the child expression.
+  // decltype(2+2);
+  // ~~~~~~~~~~~~~ <-- correct range
+  // ~~~~~~~~      <-- range reported by getSourceRange()
+  // ~~~~~~~~~~~~  <-- range with this hack(i.e, missing closing paren)
+  // FIXME: Alter DecltypeTypeLoc to contain parentheses locations and get
+  // rid of this patch.
+  if (const auto *TL = N.get<TypeLoc>()) {
+    if (auto DT = TL->getAs<DecltypeTypeLoc>()) {
+      SourceRange S = DT.getSourceRange();
+      S.setEnd(DT.getUnderlyingExpr()->getEndLoc());
+      return S;
+    }
+  }
   // MemberExprs to implicitly access anonymous fields should not claim any
   // tokens for themselves. Given:
   //   struct A { struct { int b; }; };
@@ -647,17 +662,6 @@ private:
       // heuristics. We should consider only pruning critical TypeLoc nodes, to
       // be more robust.
 
-      // DeclTypeTypeLoc::getSourceRange() is incomplete, which would lead to
-      // failing
-      // to descend into the child expression.
-      // decltype(2+2);
-      // ~~~~~~~~~~~~~ <-- correct range
-      // ~~~~~~~~      <-- range reported by getSourceRange()
-      // ~~~~~~~~~~~~  <-- range with this hack(i.e, missing closing paren)
-      // FIXME: Alter DecltypeTypeLoc to contain parentheses locations and get
-      // rid of this patch.
-      if (auto DT = TL->getAs<DecltypeTypeLoc>())
-        S.setEnd(DT.getUnderlyingExpr()->getEndLoc());
       // AttributedTypeLoc may point to the attribute's range, NOT the modified
       // type's range.
       if (auto AT = TL->getAs<AttributedTypeLoc>())
diff --git a/clang-tools-extra/clangd/unittests/SelectionTests.cpp b/clang-tools-extra/clangd/unittests/SelectionTests.cpp
index 971487c9cd27..6583d89af695 100644
--- a/clang-tools-extra/clangd/unittests/SelectionTests.cpp
+++ b/clang-tools-extra/clangd/unittests/SelectionTests.cpp
@@ -385,6 +385,7 @@ TEST(SelectionTest, CommonAncestor) {
         decltype([[^a]] + a) b;
         )cpp",
           "DeclRefExpr"},
+      {"[[decltype]]^(1) b;", "DecltypeTypeLoc"}, // Not the VarDecl.
 
       // Objective-C nullability attributes.
       {