[clangd] Fix hover for functions inside templated classes

[kadircet]

Summary

Fixes https://github.com/clangd/clangd/issues/235

[merge_guards_bot]

Unit tests: pass. 61043 tests passed, 0 failed and 728 were skipped.

clang-tidy: pass.

clang-format: pass.

Build artifacts: diff.json, clang-tidy.txt, clang-format.patch, CMakeCache.txt, console-log.txt, test-results.xml

[ilya-biryukov]

I landed a patch that does exactly this a few days ago:
14e11005d1a6ac1fecb230c470e9011d6956b8e4

Did you pull the latest changes?

[kadircet]

nope i haven't, thanks for taking care !

clang-tools-extra/clangd/Hover.cpp

const NamedDecl *getDeclForComment(const NamedDecl *D) {
   if (auto *CTSD = llvm::dyn_cast<ClassTemplateSpecializationDecl>(D))
     if (!CTSD->isExplicitInstantiationOrSpecialization())
       return CTSD->getTemplateInstantiationPattern();
   if (auto *VTSD = llvm::dyn_cast<VarTemplateSpecializationDecl>(D))
     if (!VTSD->isExplicitInstantiationOrSpecialization())
       return VTSD->getTemplateInstantiationPattern();
   if (auto *FD = D->getAsFunction())
     if (FD->isTemplateInstantiation())
-      return FD->getTemplateSpecializationInfo()->getTemplate();
+      return FD->getTemplateInstantiationPattern();
   return D;
 }
 
 // Look up information about D from the index, and add it to Hover.
 void enhanceFromIndex(HoverInfo &Hover, const NamedDecl &ND,
                       const SymbolIndex *Index) {
   assert(&ND == getDeclForComment(&ND));
   // We only add documentation, so don't bother if we already have some.

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

for (const auto &P : T.points()) {
     ASSERT_TRUE(H);
     EXPECT_EQ(H->Documentation, IndexSym.Documentation);
   }
 }
 
 TEST(Hover, DocsFromAST) {
   Annotations T(R"cpp(
   // doc
-  template <typename T> class X {};
+  template <typename T> class X {
+   public:
+    // doc
+    void foo();
+  };
   // doc
   template <typename T> void bar() {}
   // doc
   template <typename T> T baz;
   void foo() {
     au^to t = X<int>();
     X^<int>();
     b^ar<int>();
     au^to T = ba^z<X<int>>;
     ba^z<int> = 0;
+    X<int>().f^oo();
   })cpp");
 
   TestTU TU = TestTU::withCode(T.code());
   auto AST = TU.build();
   for (const auto &D : AST.getDiagnostics())
     ADD_FAILURE() << D;
   ASSERT_TRUE(AST.getDiagnostics().empty());
 
   for (const auto &P : T.points()) {
     auto H = getHover(AST, P, format::getLLVMStyle(), nullptr);
     ASSERT_TRUE(H);
     EXPECT_EQ(H->Documentation, "doc");
   }
 }
 
 TEST(Hover, DocsFromMostSpecial) {
   Annotations T(R"cpp(
   // doc1
-  template <typename T> class $doc1^X {};
+  template <typename T> struct $doc1^X {
+    // doc1
+    void foo();
+  };
   // doc2
-  template <> class $doc2^X<int> {};
+  template <> struct $doc2^X<int> {
+    // doc2
+    void foo();
+  };
+  // doc3
+  template <typename T> struct $doc3^X<T*> {
     // doc3
-  template <typename T> class $doc3^X<T*> {};
+    void foo();
+  };
   void foo() {
     X$doc1^<char>();
     X$doc2^<int>();
     X$doc3^<int*>();
+
+    X<char>().fo$doc1^o();
+    X<int>().fo$doc2^o();
+    X<int*>().fo$doc3^o();
   })cpp");
 
   TestTU TU = TestTU::withCode(T.code());
   auto AST = TU.build();
   for (const auto &D : AST.getDiagnostics())
     ADD_FAILURE() << D;
   ASSERT_TRUE(AST.getDiagnostics().empty());