Allow getting template args for ClassTemplateSpecializations

[anderslanglands]

Summary

Modifies clang_Cursor_getNumTemplateArguments() and friends to work on Struct, Class and ClassTemplatePartialSpecialization decls as well as functions

[anderslanglands]

Hello again, this generalizes the template argument functionality to operate on cursor kinds other than functions.

I could use some help creating a test for this. On my previous patch I was able to just copy/paste and modify an existing test, but from a quick scan of the current tests I can't see how I'd modify one of them to test this functionality.

[anderslanglands]

Updating doc comments to reflect new functionality

[aaron.ballman]

Mostly nits from me (FWIW, we use auto when the type is explicitly spelled out in the initialization and we don't usually use else after an unconditional return as a matter of coding style.) In terms of the test coverage, I would probably make a new test modeled after https://github.com/llvm/llvm-project/blob/main/clang/test/Index/cxx14-lambdas.cpp.

clang/include/clang-c/Index.h

3594–3596

Since we're in the area already...

clang/tools/libclang/CXCursor.cpp

1357

CXCursor_StructDecl is interesting -- does that only get used in C or will it also show up in C++? If it's C-only, we can drop that bit.

1372–1373

1379–1388

1404

Same question here about struct decl as above.

1410–1417

1439–1455

[anderslanglands]

Add testing, address style notes

[anderslanglands]

I ended up modifying c-index-test to print out the template arguments in the same way it does for FunctionDecl, which ends up working all cases in the existing test suite. The only other thing I added was a specific case in index-templates.cpp to check whether it catches StructDecl too (it does).

clang/tools/libclang/CXCursor.cpp

1357

It does. I added a case to index-templates.cpp that tests for this.

[aaron.ballman]

LGTM! I can fix up the minor nit with the release note formatting when I land on your behalf.

clang/docs/ReleaseNotes.rst

429–430

clang/docs/ReleaseNotes.rst

 libclang
 --------
 - Introduced the new function ``clang_getUnqualifiedType``, which mimics
   the behavior of ``QualType::getUnqualifiedType`` for ``CXType``.
 - Introduced the new function ``clang_getNonReferenceType``, which mimics
   the behavior of ``QualType::getNonReferenceType`` for ``CXType``.
 - Introduced the new function ``clang_CXXMethod_isDeleted``, which queries
   whether the method is declared ``= delete``.
+- ``clang_Cursor_getNumTemplateArguments``, ``clang_Cursor_getTemplateArgumentKind``, 
+  ``clang_Cursor_getTemplateArgumentType``, ``clang_Cursor_getTemplateArgumentValue`` and 
+  ``clang_Cursor_getTemplateArgumentUnsignedValue`` now work on struct, class,
+  and partial template specialization cursors in addition to function cursors.
 
 Static Analyzer
 ---------------
 - Removed the deprecated ``-analyzer-store`` and
   ``-analyzer-opt-analyze-nested-blocks`` analyzer flags.
   ``scanbuild`` was also updated accordingly.
   Passing these flags will result in a hard error.
 

clang/include/clang-c/Index.h

enum CXTemplateArgumentKind {
   CXTemplateArgumentKind_TemplateExpansion,
   CXTemplateArgumentKind_Expression,
   CXTemplateArgumentKind_Pack,
   /* Indicates an error case, preventing the kind from being deduced. */
   CXTemplateArgumentKind_Invalid
 };
 
 /**
- *Returns the number of template args of a function decl representing a
- * template specialization.
+ * Returns the number of template args of a function, struct, or class decl
+ * representing a template specialization.
  *
  * If the argument cursor cannot be converted into a template function
  * declaration, -1 is returned.
  *
  * For example, for the following declaration and specialization:
  *   template <typename T, int kInt, bool kBool>
  *   void foo() { ... }
  *
  *   template <>
  *   void foo<float, -7, true>();
  *
  * The value 3 would be returned from this call.
  */
 CINDEX_LINKAGE int clang_Cursor_getNumTemplateArguments(CXCursor C);
 
 /**
  * Retrieve the kind of the I'th template argument of the CXCursor C.
  *
- * If the argument CXCursor does not represent a FunctionDecl, an invalid
- * template argument kind is returned.
+ * If the argument CXCursor does not represent a FunctionDecl, StructDecl, or
+ * ClassTemplatePartialSpecialization, an invalid template argument kind is
+ * returned.
  *
  * For example, for the following declaration and specialization:
  *   template <typename T, int kInt, bool kBool>
  *   void foo() { ... }
  *
  *   template <>
  *   void foo<float, -7, true>();
  *
  * For I = 0, 1, and 2, Type, Integral, and Integral will be returned,
  * respectively.
  */
 CINDEX_LINKAGE enum CXTemplateArgumentKind
 clang_Cursor_getTemplateArgumentKind(CXCursor C, unsigned I);
 
 /**
  * Retrieve a CXType representing the type of a TemplateArgument of a
  *  function decl representing a template specialization.
  *
- * If the argument CXCursor does not represent a FunctionDecl whose I'th
- * template argument has a kind of CXTemplateArgKind_Integral, an invalid type
- * is returned.
+ * If the argument CXCursor does not represent a FunctionDecl, StructDecl,
+ * ClassDecl or ClassTemplatePartialSpecialization whose I'th template argument
+ * has a kind of CXTemplateArgKind_Integral, an invalid type is returned.
  *
  * For example, for the following declaration and specialization:
  *   template <typename T, int kInt, bool kBool>
  *   void foo() { ... }
  *
  *   template <>
  *   void foo<float, -7, true>();
  *
  * If called with I = 0, "float", will be returned.
  * Invalid types will be returned for I == 1 or 2.
  */
 CINDEX_LINKAGE CXType clang_Cursor_getTemplateArgumentType(CXCursor C,
                                                            unsigned I);
 
 /**
  * Retrieve the value of an Integral TemplateArgument (of a function
  *  decl representing a template specialization) as a signed long long.
  *
  * It is undefined to call this function on a CXCursor that does not represent a
- * FunctionDecl or whose I'th template argument is not an integral value.
+ * FunctionDecl, StructDecl, ClassDecl or ClassTemplatePartialSpecialization
+ * whose I'th template argument is not an integral value.
  *
  * For example, for the following declaration and specialization:
  *   template <typename T, int kInt, bool kBool>
  *   void foo() { ... }
  *
  *   template <>
  *   void foo<float, -7, true>();
  *
  * If called with I = 1 or 2, -7 or true will be returned, respectively.
  * For I == 0, this function's behavior is undefined.
  */
 CINDEX_LINKAGE long long clang_Cursor_getTemplateArgumentValue(CXCursor C,
                                                                unsigned I);
 
 /**
  * Retrieve the value of an Integral TemplateArgument (of a function
  *  decl representing a template specialization) as an unsigned long long.
  *
  * It is undefined to call this function on a CXCursor that does not represent a
- * FunctionDecl or whose I'th template argument is not an integral value.
+ * FunctionDecl, StructDecl, ClassDecl or ClassTemplatePartialSpecialization or
+ * whose I'th template argument is not an integral value.
  *
  * For example, for the following declaration and specialization:
  *   template <typename T, int kInt, bool kBool>
  *   void foo() { ... }
  *
  *   template <>
  *   void foo<float, 2147483649, true>();
  *

clang/test/Index/get-cursor.cpp

 // RUN: c-index-test -cursor-at=%s:45:9 %s | FileCheck -check-prefix=CHECK-LOCALCLASS %s
 // CHECK-LOCALCLASS: 45:9 DeclRefExpr=x:44:11 Extent=[45:9 - 45:10] Spelling=x ([45:9 - 45:10])
 
 // RUN: c-index-test -cursor-at=%s:50:23 -cursor-at=%s:55:23 %s | FileCheck -check-prefix=CHECK-TEMPLPARAM %s
 // CHECK-TEMPLPARAM: 50:23 TypeRef=struct X:3:8 Extent=[50:23 - 50:24] Spelling=struct X ([50:23 - 50:24])
 // CHECK-TEMPLPARAM: 55:23 TypeRef=struct X:3:8 Extent=[55:23 - 55:24] Spelling=struct X ([55:23 - 55:24])
 
 // RUN: c-index-test -cursor-at=%s:66:23 %s | FileCheck -check-prefix=CHECK-TEMPLSPEC %s
-// CHECK-TEMPLSPEC: 66:23 ClassDecl=TC:66:23 (Definition) [Specialization of TC:59:7] Extent=[66:1 - 66:31] Spelling=TC ([66:23 - 66:25])
+// CHECK-TEMPLSPEC: 66:23 ClassDecl=TC:66:23 (Definition) [Specialization of TC:59:7] [Template arg 0: kind: 1, type: char] Extent=[66:1 - 66:31] Spelling=TC ([66:23 - 66:25])
 
 // RUN: c-index-test -cursor-at=%s:69:3 -cursor-at=%s:70:11 -cursor-at=%s:73:6 -cursor-at=%s:74:6 -cursor-at=%s:77:8 -cursor-at=%s:78:8 -cursor-at=%s:79:8 -cursor-at=%s:80:8 -cursor-at=%s:81:8 -cursor-at=%s:82:8 -cursor-at=%s:85:6 -cursor-at=%s:86:6 -cursor-at=%s:87:6 -cursor-at=%s:88:6 -cursor-at=%s:91:5 -cursor-at=%s:92:5 -cursor-at=%s:93:5 -cursor-at=%s:94:5 -cursor-at=%s:95:5 -cursor-at=%s:96:5 -cursor-at=%s:97:5 -cursor-at=%s:98:5 -cursor-at=%s:100:5 -cursor-at=%s:101:5 -cursor-at=%s:104:6 -cursor-at=%s:105:6 -cursor-at=%s:106:6 -cursor-at=%s:107:6 -cursor-at=%s:108:6 -cursor-at=%s:109:6 -cursor-at=%s:110:6 -cursor-at=%s:111:6 -cursor-at=%s:113:6 -cursor-at=%s:114:6 -cursor-at=%s:117:8 -cursor-at=%s:118:8 -cursor-at=%s:120:8 -cursor-at=%s:121:8 -cursor-at=%s:122:8 -cursor-at=%s:123:8 -cursor-at=%s:124:8 -cursor-at=%s:125:8 -cursor-at=%s:128:6 -cursor-at=%s:129:6 -cursor-at=%s:130:6 -cursor-at=%s:132:3 -cursor-at=%s:146:15 -cursor-at=%s:149:6 -cursor-at=%s:150:25 -cursor-at=%s:151:6 -cursor-at=%s:152:6 -cursor-at=%s:153:6 -cursor-at=%s:154:6 -cursor-at=%s:155:6 -std=c++11 %s | FileCheck -check-prefix=CHECK-SPELLING %s
 // CHECK-SPELLING: 69:3 CXXConstructor=A:69:3 (default constructor) Extent=[69:3 - 69:6] Spelling=A ([69:3 - 69:4])
 // CHECK-SPELLING: 70:11 CXXDestructor=~A:70:11 (virtual) Extent=[70:3 - 70:15] Spelling=~A ([70:11 - 70:13])
 // CHECK-SPELLING: 73:6 CXXMethod=operator=:73:6 Extent=[73:3 - 73:25] Spelling=operator= ([73:6 - 73:15])
 // CHECK-SPELLING: 74:6 CXXMethod=operator=:74:6 (noexcept) Extent=[74:3 - 74:29] Spelling=operator= ([74:6 - 74:15])
 // CHECK-SPELLING: 77:8 CXXMethod=operator+:77:8 (const) Extent=[77:3 - 77:25] Spelling=operator+ ([77:8 - 77:17])
 // CHECK-SPELLING: 78:8 CXXMethod=operator-:78:8 (const) Extent=[78:3 - 78:25] Spelling=operator- ([78:8 - 78:17])

clang/test/Index/index-templates.cpp

 // CHECK-LOAD: index-templates.cpp:4:13: DeclRefExpr=Value:3:24 Extent=[4:13 - 4:18]
 // CHECK-LOAD: index-templates.cpp:6:28: ClassTemplate=allocator:6:28 Extent=[6:1 - 6:37]
 // CHECK-LOAD: index-templates.cpp:6:19: TemplateTypeParameter=T:6:19 (Definition) Extent=[6:10 - 6:20]
 // CHECK-LOAD: index-templates.cpp:9:7: ClassTemplate=vector:9:7 (Definition) Extent=[8:1 - 11:2]
 // CHECK-LOAD: index-templates.cpp:8:19: TemplateTypeParameter=T:8:19 (Definition) Extent=[8:10 - 8:20]
 // CHECK-LOAD: index-templates.cpp:8:31: TemplateTypeParameter=Alloc:8:31 (Definition) Extent=[8:22 - 8:51]
 // CHECK-LOAD: index-templates.cpp:8:39: TemplateRef=allocator:6:28 Extent=[8:39 - 8:48]
 // CHECK-LOAD: index-templates.cpp:10:8: CXXMethod=clear:10:8 Extent=[10:3 - 10:15]
-// CHECK-LOAD: index-templates.cpp:14:7: ClassTemplatePartialSpecialization=vector:14:7 (Definition) [Specialization of vector:9:7] Extent=[13:1 - 14:21]
+// CHECK-LOAD: index-templates.cpp:14:7: ClassTemplatePartialSpecialization=vector:14:7 (Definition) [Specialization of vector:9:7] [Template arg 0: kind: 1, type: type-parameter-0-0 *] [Template arg 1: kind: 1, type: allocator<type-parameter-0-0 *>] Extent=[13:1 - 14:21]
 // CHECK-LOAD: index-templates.cpp:13:19: TemplateTypeParameter=T:13:19 (Definition) Extent=[13:10 - 13:20]
 // CHECK-LOAD: index-templates.cpp:16:8: StructDecl=Z1:16:8 (Definition) Extent=[16:1 - 16:14]
-// CHECK-LOAD: index-templates.cpp:18:16: ClassDecl=vector:18:16 (Definition) [Specialization of vector:9:7] Extent=[18:1 - 18:26]
+// CHECK-LOAD: index-templates.cpp:18:16: ClassDecl=vector:18:16 (Definition) [Specialization of vector:9:7] [Template arg 0: kind: 1, type: Z1] [Template arg 1: kind: 1, type: allocator<Z1>] Extent=[18:1 - 18:26]
 // CHECK-LOAD: index-templates.cpp:18:23: TypeRef=struct Z1:16:8 Extent=[18:23 - 18:25]
 // CHECK-LOAD-NOT: CXXMethod=clear
 // CHECK-LOAD: index-templates.cpp:20:8: StructDecl=Z2:20:8 (Definition) Extent=[20:1 - 20:14]
-// CHECK-LOAD: index-templates.cpp:23:7: ClassDecl=vector:23:7 (Definition) [Specialization of vector:9:7] Extent=[22:1 - 25:2]
+// CHECK-LOAD: index-templates.cpp:23:7: ClassDecl=vector:23:7 (Definition) [Specialization of vector:9:7] [Template arg 0: kind: 1, type: Z2] [Template arg 1: kind: 1, type: allocator<Z2>] Extent=[22:1 - 25:2]
 // CHECK-LOAD: index-templates.cpp:23:14: TypeRef=struct Z2:20:8 Extent=[23:14 - 23:16]
 // CHECK-LOAD: index-templates.cpp:24:8: CXXMethod=clear:24:8 Extent=[24:3 - 24:15]
 // CHECK-LOAD: index-templates.cpp:28:8: ClassTemplate=Y:28:8 (Definition) Extent=[27:1 - 31:2]
 // CHECK-LOAD: index-templates.cpp:27:19: TemplateTypeParameter=T:27:19 (Definition) Extent=[27:10 - 27:20]
 // CHECK-LOAD: index-templates.cpp:27:31: TemplateTypeParameter=U:27:31 (Definition) Extent=[27:22 - 27:32]
 // CHECK-LOAD: index-templates.cpp:29:21: UsingDeclaration=type:29:21 Extent=[29:3 - 29:25]
 // CHECK-LOAD: index-templates.cpp:30:12: UsingDeclaration=operator Z2:30:12 Extent=[30:3 - 30:23]
 // CHECK-LOAD: index-templates.cpp:30:21: TypeRef=struct Z2:20:8 Extent=[30:21 - 30:23]

 // CHECK-LOAD: index-templates.cpp:39:27: TemplateTypeParameter=:39:27 (Definition) Extent=[39:19 - 39:27]
 // CHECK-LOAD: index-templates.cpp:39:37: NonTypeTemplateParameter=:39:37 (Definition) Extent=[39:29 - 39:37]
 // CHECK-LOAD: index-templates.cpp:39:61: TemplateRef=array:37:8 Extent=[39:61 - 39:66]
 // CHECK-LOAD: index-templates.cpp:42:18: TypedefDecl=Unsigned:42:18 (Definition) Extent=[42:1 - 42:26]
 // CHECK-LOAD: index-templates.cpp:45:8: ClassTemplate=value_c:45:8 Extent=[44:1 - 45:15]
 // CHECK-LOAD: index-templates.cpp:44:19: TemplateTypeParameter=T:44:19 (Definition) Extent=[44:10 - 44:20]
 // CHECK-LOAD: index-templates.cpp:44:31: NonTypeTemplateParameter=Value:44:31 (Definition) Extent=[44:22 - 44:36]
 // CHECK-LOAD: index-templates.cpp:44:22: TypeRef=Unsigned:42:18 Extent=[44:22 - 44:30]
-// CHECK-LOAD: index-templates.cpp:47:16: ClassDecl=vector:47:16 (Definition) [Specialization of vector:14:7] Extent=[47:1 - 47:28]
+// CHECK-LOAD: index-templates.cpp:47:16: ClassDecl=vector:47:16 (Definition) [Specialization of vector:14:7] [Template arg 0: kind: 1, type: int *] [Template arg 1: kind: 1, type: allocator<int *>] Extent=[47:1 - 47:28]
 // CHECK-LOAD: index-templates.cpp:49:8: StructDecl=Z4:49:8 (Definition) Extent=[49:1 - 51:2]
 // CHECK-LOAD: index-templates.cpp:50:26: FunctionTemplate=getAs:50:26 Extent=[50:3 - 50:33]
 // CHECK-LOAD: index-templates.cpp:50:21: TemplateTypeParameter=T:50:21 (Definition) Extent=[50:12 - 50:22]
 // CHECK-LOAD: index-templates.cpp:53:6: FunctionDecl=template_exprs:53:6 (Definition)
 // CHECK-LOAD: index-templates.cpp:54:3: CallExpr=f:4:6 Extent=[54:3 - 54:68]
 // CHECK-LOAD: index-templates.cpp:54:3: UnexposedExpr=f:4:6 Extent=[54:3 - 54:35]
 // CHECK-LOAD: index-templates.cpp:54:3: DeclRefExpr=f:4:6 RefName=[54:3 - 54:4] RefName=[54:4 - 54:35] Extent=[54:3 - 54:35]
 // CHECK-LOAD: index-templates.cpp:54:5: TypeRef=Unsigned:42:18 Extent=[54:5 - 54:13]
 // CHECK-LOAD: index-templates.cpp:54:15: DeclRefExpr=OneDimension:35:16 Extent=[54:15 - 54:27]
 // CHECK-LOAD: index-templates.cpp:54:29: TemplateRef=value:52:32 Extent=[54:29 - 54:34]
 // CHECK-LOAD: index-templates.cpp:55:8: MemberRefExpr=getAs:50:26 SingleRefName=[55:8 - 55:13] RefName=[55:8 - 55:13] Extent=[55:3 - 55:23]
 // CHECK-LOAD: index-templates.cpp:55:3: CallExpr=Z4:49:8 Extent=[55:3 - 55:7]
 // CHECK-LOAD: index-templates.cpp:55:14: TypeRef=Unsigned:42:18 Extent=[55:14 - 55:22]
 // CHECK-LOAD: index-templates.cpp:68:6: FunctionTemplate=unresolved_exprs:68:6 (Definition)
 // CHECK-LOAD: index-templates.cpp:69:3: OverloadedDeclRef=swap[60:6, 59:39, 58:27]
 // CHECK-LOAD: index-templates.cpp:71:6: OverloadedDeclRef=f[63:7, 64:9]
 // CHECK-LOAD: index-templates.cpp:72:3: OverloadedDeclRef=swap[58:27, 59:39]
 // CHECK-LOAD: index-templates.cpp:82:6: FunctionTemplate=init_list:82:6 (Definition)
 // CHECK-LOAD: index-templates.cpp:85:14: VarDecl=p:85:14 (Definition)
 // CHECK-LOAD: index-templates.cpp:85:20: DeclRefExpr=t:82:18 Extent=[85:20 - 85:21]
 // CHECK-LOAD: index-templates.cpp:85:23: TypeRef=second_type:83:13 Extent=[85:23 - 85:34]
 // CHECK-LOAD: index-templates.cpp:85:35: DeclRefExpr=u:82:23 Extent=[85:35 - 85:36]
+// CHECK-LOAD: index-templates.cpp:98:16: StructDecl=Pair:98:16 (Definition) [Specialization of Pair:76:8] [Template arg 0: kind: 1, type: int] [Template arg 1: kind: 1, type: int] Extent=[98:1 - 98:30]
 // CHECK-LOAD: index-templates.cpp:101:8: ClassTemplate=SuperPair:101:8 (Definition) Extent=[100:1 - 101:50]
 // CHECK-LOAD: index-templates.cpp:100:19: TemplateTypeParameter=T:100:19 (Definition) Extent=[100:10 - 100:20]
 // CHECK-LOAD: index-templates.cpp:100:31: TemplateTypeParameter=U:100:31 (Definition) Extent=[100:22 - 100:32]
 // CHECK-LOAD: index-templates.cpp:101:20: C++ base class specifier=Pair<int, int>:98:16 [access=public isVirtual=false] Extent=[101:20 - 101:34]
 // CHECK-LOAD: index-templates.cpp:101:36: C++ base class specifier=Pair<T, U>:76:8 [access=public isVirtual=false] Extent=[101:36 - 101:46]
 // CHECK-LOAD: index-templates.cpp:111:6: FunctionDecl=foo:111:6 [Specialization of foo:107:6] [Template arg 0: kind: 1, type: float] [Template arg 1: kind: 4, intval: 9] [Template arg 2: kind: 4, intval: 1] [Template arg 3: kind: 4, intval: 14] Extent=[110:1 - 111:64]
 // CHECK-LOAD: index-templates.cpp:114:1: TypeAliasTemplateDecl=alias:114:1 (Definition) Extent=[113:1 - 114:16]
 // CHECK-LOAD: index-templates.cpp:113:17: TemplateTypeParameter=T:113:17 (Definition) Extent=[113:11 - 113:18] [access=public]

clang/test/Index/print-display-names.cpp

 // DISPLAY_NAME: print-display-names.cpp:6:16: ClassDecl=ClassTmpl<Integer, Integer>:6:16 (Definition)
 // DISPLAY_NAME: print-display-names.cpp:8:6: FunctionDecl=f(ClassTmpl<float, Integer>):8:6
 // DISPLAY_NAME: print-display-names.cpp:11:6: FunctionTemplate=g(ClassTmpl<T, T>):11:6
 // DISPLAY_NAME: print-display-names.cpp:13:17: FunctionDecl=g<>(ClassTmpl<int, int>):13:17 [Specialization of g:11:6]
 
 // RUN: env CINDEXTEST_PRINTINGPOLICY_TERSEOUTPUT=1 c-index-test -test-load-source all-pretty %s | FileCheck %s --check-prefix=PRETTY
 // PRETTY: print-display-names.cpp:2:7: ClassTemplate=template <typename T, typename> class ClassTmpl {}:2:7 (Definition) Extent=[1:1 - 2:20]
 // PRETTY: print-display-names.cpp:4:13: TypedefDecl=typedef int Integer:4:13 (Definition) Extent=[4:1 - 4:20]
-// PRETTY: print-display-names.cpp:6:16: ClassDecl=template<> class ClassTmpl<Integer, Integer> {}:6:16 (Definition) [Specialization of ClassTmpl:2:7] Extent=[6:1 - 6:43]
+// PRETTY: print-display-names.cpp:6:16: ClassDecl=template<> class ClassTmpl<Integer, Integer> {}:6:16 (Definition) [Specialization of ClassTmpl:2:7] [Template arg 0: kind: 1, type: int] [Template arg 1: kind: 1, type: int] Extent=[6:1 - 6:43]
 // PRETTY: print-display-names.cpp:8:6: FunctionDecl=void f(ClassTmpl<float, Integer> p):8:6 Extent=[8:1 - 8:36]
 // PRETTY: print-display-names.cpp:8:34: ParmDecl=ClassTmpl<float, Integer> p:8:34 (Definition) Extent=[8:8 - 8:35]
 // PRETTY: print-display-names.cpp:11:6: FunctionTemplate=template <typename T> void g(ClassTmpl<T, T>):11:6 Extent=[10:1 - 11:24]
 // PRETTY: print-display-names.cpp:11:23: ParmDecl=ClassTmpl<T, T>:11:23 (Definition) Extent=[11:8 - 11:23]
 // PRETTY: print-display-names.cpp:13:17: FunctionDecl=template<> void g<int>(ClassTmpl<int, int>):13:17 [Specialization of g:11:6] [Template arg 0: kind: 1, type: int] Extent=[13:1 - 13:44]
 // PRETTY: print-display-names.cpp:13:43: ParmDecl=ClassTmpl<int, int>:13:43 (Definition) Extent=[13:24 - 13:43]

clang/test/Index/print-type.cpp

 // CHECK: VarDecl=autoInt:58:16 (Definition) [type=int] [typekind=Auto] [canonicaltype=int] [canonicaltypekind=Int] [isPOD=1]
 // CHECK: IntegerLiteral= [type=int] [typekind=Int] [isPOD=1]
 // CHECK: TypeAliasTemplateDecl=TypeAlias:61:1 (Definition) [type=] [typekind=Invalid] [isPOD=0]
 // CHECK: TemplateTypeParameter=T:60:20 (Definition) [type=T] [typekind=Unexposed] [canonicaltype=type-parameter-0-0] [canonicaltypekind=Unexposed] [isPOD=0]
 // CHECK: FieldDecl=foo:63:39 (Definition) [type=TypeAlias<int>] [typekind=Elaborated] [templateargs/1= [type=int] [typekind=Int]] [canonicaltype=outer::Qux<int>] [canonicaltypekind=Record] [canonicaltemplateargs/1= [type=int] [typekind=Int]] [isPOD=1]
 // CHECK: TemplateRef=TypeAlias:61:1 [type=] [typekind=Invalid] [isPOD=0]
 // CHECK: ClassTemplate=Specialization:66:8 (Definition) [type=] [typekind=Invalid] [isPOD=0]
 // CHECK: TemplateTypeParameter=T:65:19 (Definition) [type=T] [typekind=Unexposed] [canonicaltype=type-parameter-0-0] [canonicaltypekind=Unexposed] [isPOD=0]
-// CHECK: StructDecl=Specialization:69:8 [Specialization of Specialization:66:8] [type=Specialization<int>] [typekind=Record] [templateargs/1= [type=int] [typekind=Int]] [isPOD=0]
+// CHECK: StructDecl=Specialization:69:8 [Specialization of Specialization:66:8] [Template arg 0: kind: 1, type: int] [type=Specialization<int>] [typekind=Record] [templateargs/1= [type=int] [typekind=Int]] [isPOD=0]
 // CHECK: VarDecl=templRefParam:71:40 (Definition) [type=Specialization<Specialization<bool> &>] [typekind=Elaborated] [templateargs/1= [type=Specialization<bool> &] [typekind=LValueReference]] [canonicaltype=Specialization<Specialization<bool> &>] [canonicaltypekind=Record] [canonicaltemplateargs/1= [type=Specialization<bool> &] [typekind=LValueReference]] [isPOD=1]
 // CHECK: TemplateRef=Specialization:66:8 [type=] [typekind=Invalid] [isPOD=0]
 // CHECK: CallExpr=Specialization:66:8 [type=Specialization<Specialization<bool> &>] [typekind=Elaborated] [templateargs/1= [type=Specialization<bool> &] [typekind=LValueReference]] [canonicaltype=Specialization<Specialization<bool> &>] [canonicaltypekind=Record] [canonicaltemplateargs/1= [type=Specialization<bool> &] [typekind=LValueReference]] [isPOD=1]
 // CHECK: VarDecl=autoTemplRefParam:72:6 (Definition) [type=Specialization<Specialization<bool> &>] [typekind=Auto] [templateargs/1= [type=Specialization<bool> &] [typekind=LValueReference]] [canonicaltype=Specialization<Specialization<bool> &>] [canonicaltypekind=Record] [canonicaltemplateargs/1= [type=Specialization<bool> &] [typekind=LValueReference]] [isPOD=1]
 // CHECK: UnexposedExpr=templRefParam:71:40 [type=const Specialization<Specialization<bool> &>] [typekind=Record] const [templateargs/1= [type=Specialization<bool> &] [typekind=LValueReference]] [isPOD=1]
 // CHECK: DeclRefExpr=templRefParam:71:40 [type=Specialization<Specialization<bool> &>] [typekind=Elaborated] [templateargs/1= [type=Specialization<bool> &] [typekind=LValueReference]] [canonicaltype=Specialization<Specialization<bool> &>] [canonicaltypekind=Record] [canonicaltemplateargs/1= [type=Specialization<bool> &] [typekind=LValueReference]] [isPOD=1]
 // CHECK: TypeAliasDecl=baz:76:7 (Definition) [type=baz] [typekind=Typedef] [templateargs/1= [type=A<void>] [typekind=Elaborated]] [canonicaltype=A<void>] [canonicaltypekind=Record] [canonicaltemplateargs/1= [type=void] [typekind=Void]] [isPOD=0]
 // CHECK: VarDecl=autoTemplPointer:78:6 (Definition) [type=Specialization<Specialization<bool> &> *] [typekind=Auto] [canonicaltype=Specialization<Specialization<bool> &> *] [canonicaltypekind=Pointer] [isPOD=1] [pointeetype=Specialization<Specialization<bool> &>] [pointeekind=Auto]
 // CHECK: CallExpr=Bar:17:3 [type=outer::inner::Bar] [typekind=Elaborated] [canonicaltype=outer::inner::Bar] [canonicaltypekind=Record] [args= [outer::Foo<bool> *] [Pointer]] [isPOD=0] [nbFields=3]
 // CHECK: StructDecl=:84:3 (Definition) [type=X::(anonymous struct at {{.*}}print-type.cpp:84:3)] [typekind=Record] [isPOD=1] [nbFields=1] [isAnon=1]
 // CHECK: ClassDecl=:85:3 (Definition) [type=X::(anonymous class at {{.*}}print-type.cpp:85:3)] [typekind=Record] [isPOD=1] [nbFields=1] [isAnon=1]
 // CHECK: UnionDecl=:86:3 (Definition) [type=X::(anonymous union at {{.*}}print-type.cpp:86:3)] [typekind=Record] [isPOD=1] [nbFields=2] [isAnon=1]
 // CHECK: EnumDecl=:87:3 (Definition) [type=X::(unnamed enum at {{.*}}print-type.cpp:87:3)] [typekind=Enum] [isPOD=1] [isAnon=1]
 // CHECK: Namespace=:90:11 (Definition) [type=] [typekind=Invalid] [isPOD=0] [isAnon=1]
 // CHECK: Namespace=InlineNS:94:18 (Definition) [type=] [typekind=Invalid] [isPOD=0] [isAnonRecDecl=0] [isInlineNamespace=1]

clang/tools/c-index-test/c-index-test.c

else {
     if (!clang_equalCursors(SpecializationOf, clang_getNullCursor())) {
       CXSourceLocation Loc = clang_getCursorLocation(SpecializationOf);
       CXString Name = clang_getCursorSpelling(SpecializationOf);
       clang_getSpellingLocation(Loc, 0, &line, &column, 0);
       printf(" [Specialization of %s:%d:%d]",
              clang_getCString(Name), line, column);
       clang_disposeString(Name);
 
-      if (Cursor.kind == CXCursor_FunctionDecl) {
+      if (Cursor.kind == CXCursor_FunctionDecl
+          || Cursor.kind == CXCursor_StructDecl
+          || Cursor.kind == CXCursor_ClassDecl
+          || Cursor.kind == CXCursor_ClassTemplatePartialSpecialization) {
         /* Collect the template parameter kinds from the base template. */
         int NumTemplateArgs = clang_Cursor_getNumTemplateArguments(Cursor);
         int I;
         if (NumTemplateArgs < 0) {
           printf(" [no template arg info]");
         }
         for (I = 0; I < NumTemplateArgs; I++) {
           enum CXTemplateArgumentKind TAK =

clang/tools/libclang/CXCursor.cpp

if (const CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(E)) {
       }
     }
   }
 
   return clang_getNullCursor();
 }
 
 int clang_Cursor_getNumTemplateArguments(CXCursor C) {
-  if (clang_getCursorKind(C) != CXCursor_FunctionDecl) {
-    return -1;
-  }
-
-  const FunctionDecl *FD =
-      llvm::dyn_cast_or_null<clang::FunctionDecl>(getCursorDecl(C));
-  if (!FD) {
+  CXCursorKind kind = clang_getCursorKind(C);
+  if (kind != CXCursor_FunctionDecl && kind != CXCursor_StructDecl &&
+      kind != CXCursor_ClassDecl &&
+      kind != CXCursor_ClassTemplatePartialSpecialization) {
     return -1;
   }
 
+  if (const auto *FD =
+          llvm::dyn_cast_if_present<clang::FunctionDecl>(getCursorDecl(C))) {
     const FunctionTemplateSpecializationInfo *SpecInfo =
         FD->getTemplateSpecializationInfo();
     if (!SpecInfo) {
       return -1;
     }
-
     return SpecInfo->TemplateArguments->size();
   }
 
+  if (const auto *SD =
+          llvm::dyn_cast_if_present<clang::ClassTemplateSpecializationDecl>(
+              getCursorDecl(C))) {
+    return SD->getTemplateArgs().size();
+  }
+
+  return -1;
+}
+
 enum CXGetTemplateArgumentStatus {
   /** The operation completed successfully */
   CXGetTemplateArgumentStatus_Success = 0,
 
-  /** The specified cursor did not represent a FunctionDecl. */
-  CXGetTemplateArgumentStatus_CursorNotFunctionDecl = -1,
-
-  /** The specified cursor was not castable to a FunctionDecl. */
-  CXGetTemplateArgumentStatus_BadFunctionDeclCast = -2,
+  /** The specified cursor did not represent a FunctionDecl or
+      ClassTemplateSpecializationDecl.                         */
+  CXGetTemplateArgumentStatus_CursorNotCompatibleDecl = -1,
+
+  /** The specified cursor was not castable to a FunctionDecl or
+      ClassTemplateSpecializationDecl.                         */
+  CXGetTemplateArgumentStatus_BadDeclCast = -2,
 
   /** A NULL FunctionTemplateSpecializationInfo was retrieved. */
   CXGetTemplateArgumentStatus_NullTemplSpecInfo = -3,
 
   /** An invalid (OOB) argument index was specified */
   CXGetTemplateArgumentStatus_InvalidIndex = -4
 };
 
 static int clang_Cursor_getTemplateArgument(CXCursor C, unsigned I,
                                             TemplateArgument *TA) {
-  if (clang_getCursorKind(C) != CXCursor_FunctionDecl) {
-    return CXGetTemplateArgumentStatus_CursorNotFunctionDecl;
+  CXCursorKind kind = clang_getCursorKind(C);
+  if (kind != CXCursor_FunctionDecl && kind != CXCursor_StructDecl &&
+      kind != CXCursor_ClassDecl &&
+      kind != CXCursor_ClassTemplatePartialSpecialization) {
+    return -1;
   }
 
-  const FunctionDecl *FD =
-      llvm::dyn_cast_or_null<clang::FunctionDecl>(getCursorDecl(C));
-  if (!FD) {
-    return CXGetTemplateArgumentStatus_BadFunctionDeclCast;
-  }
+  if (const auto *FD =
+          llvm::dyn_cast_if_present<clang::FunctionDecl>(getCursorDecl(C))) {
 
     const FunctionTemplateSpecializationInfo *SpecInfo =
         FD->getTemplateSpecializationInfo();
     if (!SpecInfo) {
       return CXGetTemplateArgumentStatus_NullTemplSpecInfo;
     }
 
     if (I >= SpecInfo->TemplateArguments->size()) {
       return CXGetTemplateArgumentStatus_InvalidIndex;
     }
 
     *TA = SpecInfo->TemplateArguments->get(I);
     return 0;
   }
 
+  if (const auto *SD =
+          llvm::dyn_cast_if_present<clang::ClassTemplateSpecializationDecl>(
+              getCursorDecl(C))) {
+    if (I >= SD->getTemplateArgs().size()) {
+      return CXGetTemplateArgumentStatus_InvalidIndex;
+    }
+
+    *TA = SD->getTemplateArgs()[I];
+    return 0;
+  }
+
+  return CXGetTemplateArgumentStatus_BadDeclCast;
+}
+
 enum CXTemplateArgumentKind clang_Cursor_getTemplateArgumentKind(CXCursor C,
                                                                  unsigned I) {
   TemplateArgument TA;
   if (clang_Cursor_getTemplateArgument(C, I, &TA)) {
     return CXTemplateArgumentKind_Invalid;
   }
 
   switch (TA.getKind()) {
   case TemplateArgument::Null:
     return CXTemplateArgumentKind_Null;
   case TemplateArgument::Type:
     return CXTemplateArgumentKind_Type;
   case TemplateArgument::Declaration:
     return CXTemplateArgumentKind_Declaration;
   case TemplateArgument::NullPtr:
     return CXTemplateArgumentKind_NullPtr;
   case TemplateArgument::Integral:
     return CXTemplateArgumentKind_Integral;
   case TemplateArgument::Template:
     return CXTemplateArgumentKind_Template;
   case TemplateArgument::TemplateExpansion:
     return CXTemplateArgumentKind_TemplateExpansion;
   case TemplateArgument::Expression: