[clangd] Fix a crash in Selection

Summary:
The assertion checking that a range of a node is a token range does
not hold in case of "split" tokens, e.g. between two closing template
argument lists (`vector<vector<int>>`).

Reviewers: kadircet, sammccall

Reviewed By: kadircet

Subscribers: ioeric, MaskRay, jkorous, arphaman, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D58447

llvm-svn: 354507

clang-tools-extra/clangd/Selection.cpp

@@ -198,11 +198,10 @@ private:
       auto E = SM.getDecomposedLoc(R.getEnd());
       if (B.first != SelFile || E.first != SelFile)
         continue;
-      assert(R.isTokenRange());
       // Try to cover up to the next token, spaces between children don't count.
       if (auto Tok = Lexer::findNextToken(R.getEnd(), SM, LangOpts))
         E.second = SM.getFileOffset(Tok->getLocation());
-      else
+      else if (R.isTokenRange())
         E.second += Lexer::MeasureTokenLength(R.getEnd(), SM, LangOpts);
       ChildRanges.push_back({B.second, E.second});
     }

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

@@ -232,6 +232,11 @@ TEST(SelectionTest, Selected) {
           }]]]]
         }
       )cpp",
+      R"cpp(
+          template <class T>
+          struct unique_ptr {};
+          void foo(^$C[[unique_ptr<unique_ptr<$C[[int]]>>]]^ a) {}
+      )cpp",
   };
   for (const char *C : Cases) {
     Annotations Test(C);