[clangd] Add tests for template specializations

[ilya-biryukov]

unittests/clangd/XRefsTests.cpp

376

While here, could wee add tests for a few more cases? They are all represented by different classes in a hierarchy in clang, so each could potentially break:

/// partial template specialization
template <class T>
struct Foo<T*> {};
^Foo<int*> x;

/// function template specializations
template <class T>
void foo(T);
template <>
void foo(int);

int x = fo^o(10);

/// variable template decls
template <class T>
T var = T();

template <>
double var<int> = 10;

double y = va^r<int>;

[kadircet]

• Add more testcases

[ilya-biryukov]

LGTM with a typo-nit :-)

unittests/clangd/XRefsTests.cpp

378

s/tmeplate/template

[kadircet]

• Fix typo and make comments start with 2 slashes

unittests/clangd/XRefsTests.cpp

const char *Tests[] = {
         void f() { my^_Test a; }
       )cpp",
 
       R"cpp(
          #define FF() class [[Test]] {};
          FF();
          void f() { T^est a; }
       )cpp",
+
+      R"cpp(
+        template <typename T>
+        struct Foo { void bar() {} };
+
+        template <>
+        struct [[Foo]]<int> { void bar() {} };
+
+        void foo() {
+          Foo<char> abc;
+          Fo^o<int> b;
+        }
+      )cpp",
+
+      R"cpp(
+        template <typename T>
+        struct [[Foo]] { void bar() {} };
+        template <>
+        struct Foo<int> { void bar() {} };
+        void foo() {
+          Fo^o<char> abc;
+          Foo<int> b;
+        }
+      )cpp",
+
+      R"cpp(// partial tmeplate specialization
+        template <typename T>
+        struct Foo { void bar() {} };
+        template <typename T>
+        struct [[Foo]]<T*> { void bar() {} };
+        ^Foo<int*> x;
+      )cpp",
+
+      R"cpp(/// function template specializations
+        template <class T>
+        void foo(T) {}
+        template <>
+        void [[foo]](int) {}
+        void bar() {
+          fo^o(10);
+        }
+      )cpp",
+
+      R"cpp(/// variable template decls
+        template <class T>
+        T var = T();
+
+        template <>
+        double [[var]]<int> = 10;
+
+        double y = va^r<int>;
+      )cpp",
   };
   for (const char *Test : Tests) {
     Annotations T(Test);
     llvm::Optional<Range> WantDecl;
     llvm::Optional<Range> WantDef;
     if (!T.ranges().empty())
       WantDecl = WantDef = T.range();
     if (!T.ranges("decl").empty())