Fix elaborated type provision by alias

Elaborated types in typedef definitions should not be short-circuited
because they may yet require full-type info according to the IWYU
policy. Otherwise, it can result in a bug when IWYU requires a full type
neither on alias declaration side nor on using side.

4 files changed, 12 insertions, 10 deletions

diff --git a/iwyu.cc b/iwyu.cc
index 5ee5da7..b437553 100644
--- a/iwyu.cc
+++ b/iwyu.cc
@@ -2667,12 +2667,6 @@ class IwyuBaseAstVisitor : public BaseAstVisitor<Derived> {
 
         parent_type = GetTypeOf(decl);
       } else if (const auto *decl = ast_node->GetParentAs<TypeDecl>()) {
-        // Elaborated types in type decls are always forward-declarable
-        // (and usually count as forward declarations themselves).
-        if (IsElaboratedTypeSpecifier(ast_node)) {
-          return true;
-        }
-
         // If we ourselves are a forward-decl -- that is, we're the type
         // component of a forward-declaration (which would be our parent
         // AST node) -- then we're forward-declarable by definition.
diff --git a/tests/cxx/iwyu_stricter_than_cpp-type_alias.h b/tests/cxx/iwyu_stricter_than_cpp-type_alias.h
index 736ee9e..aa60fd8 100644
--- a/tests/cxx/iwyu_stricter_than_cpp-type_alias.h
+++ b/tests/cxx/iwyu_stricter_than_cpp-type_alias.h
@@ -29,6 +29,9 @@ using DoesNotForwardDeclareProperlyAl = IndirectStructForwardDeclaredInD1;
 struct DirectStruct1;
 using IncludesAl = DirectStruct1;
 
+// Essentially the same; should require corresponding header inclusion here.
+using IncludesElaboratedAl = struct DirectStruct3;
+
 // Requires the full type because it does not obey rules (1) *or* (2)
 using DoesNotForwardDeclareAndIncludesAl = DirectStruct2;
 
@@ -76,7 +79,7 @@ tests/cxx/iwyu_stricter_than_cpp-type_alias.h should remove these lines:
 - template <typename T> struct TplDirectStruct1;  // lines XX-XX
 
 The full include-list for tests/cxx/iwyu_stricter_than_cpp-type_alias.h:
-#include "tests/cxx/iwyu_stricter_than_cpp-d1.h"  // for DirectStruct1, DirectStruct2, TplDirectStruct1, TplDirectStruct2
+#include "tests/cxx/iwyu_stricter_than_cpp-d1.h"  // for DirectStruct1, DirectStruct2, DirectStruct3, TplDirectStruct1, TplDirectStruct2
 #include "tests/cxx/iwyu_stricter_than_cpp-i1.h"  // for IndirectStruct1, IndirectStructForwardDeclaredInD1, TplIndirectStruct1, TplIndirectStructForwardDeclaredInD1
 struct IndirectStruct2;  // lines XX-XX
 struct IndirectStruct3;  // lines XX-XX
diff --git a/tests/cxx/iwyu_stricter_than_cpp-typedefs.h b/tests/cxx/iwyu_stricter_than_cpp-typedefs.h
index 0421a8e..e51be80 100644
--- a/tests/cxx/iwyu_stricter_than_cpp-typedefs.h
+++ b/tests/cxx/iwyu_stricter_than_cpp-typedefs.h
@@ -29,6 +29,9 @@ typedef IndirectStructForwardDeclaredInD1 DoesNotForwardDeclareProperly;
 struct DirectStruct1;
 typedef DirectStruct1 Includes;
 
+// Essentially the same; should require corresponding header inclusion here.
+typedef struct DirectStruct3 IncludesElaborated;
+
 // Requires the full type because it does not obey rules (1) *or* (2)
 typedef DirectStruct2 DoesNotForwardDeclareAndIncludes;
 
@@ -76,7 +79,7 @@ tests/cxx/iwyu_stricter_than_cpp-typedefs.h should remove these lines:
 - template <typename T> struct TplDirectStruct1;  // lines XX-XX
 
 The full include-list for tests/cxx/iwyu_stricter_than_cpp-typedefs.h:
-#include "tests/cxx/iwyu_stricter_than_cpp-d1.h"  // for DirectStruct1, DirectStruct2, TplDirectStruct1, TplDirectStruct2
+#include "tests/cxx/iwyu_stricter_than_cpp-d1.h"  // for DirectStruct1, DirectStruct2, DirectStruct3, TplDirectStruct1, TplDirectStruct2
 #include "tests/cxx/iwyu_stricter_than_cpp-i1.h"  // for IndirectStruct1, IndirectStructForwardDeclaredInD1, TplIndirectStruct1, TplIndirectStructForwardDeclaredInD1
 struct IndirectStruct2;  // lines XX-XX
 struct IndirectStruct3;  // lines XX-XX
diff --git a/tests/cxx/iwyu_stricter_than_cpp.cc b/tests/cxx/iwyu_stricter_than_cpp.cc
index c8e69bb..3a12409 100644
--- a/tests/cxx/iwyu_stricter_than_cpp.cc
+++ b/tests/cxx/iwyu_stricter_than_cpp.cc
@@ -55,6 +55,7 @@ void TestTypedefs() {
   DoesNotForwardDeclare dnfd(1);
   DoesNotForwardDeclareProperly dnfdp(2);
   Includes i(3);
+  IncludesElaborated ie(3);
   DoesNotForwardDeclareAndIncludes dnfdai(4);
   // IWYU: IndirectStruct2 is...*iwyu_stricter_than_cpp-i2.h
   DoesEverythingRight dor(5);
@@ -101,6 +102,7 @@ void TestTypeAliases() {
   DoesNotForwardDeclareAl dnfd(1);
   DoesNotForwardDeclareProperlyAl dnfdp(2);
   IncludesAl i(3);
+  IncludesElaboratedAl ie(3);
   DoesNotForwardDeclareAndIncludesAl dnfdai(4);
   // IWYU: IndirectStruct2 is...*iwyu_stricter_than_cpp-i2.h
   DoesEverythingRightAl dor(5);
@@ -240,8 +242,8 @@ The full include-list for tests/cxx/iwyu_stricter_than_cpp.cc:
 #include "tests/cxx/iwyu_stricter_than_cpp-i2.h"  // for IndirectStruct2, TplIndirectStruct2
 #include "tests/cxx/iwyu_stricter_than_cpp-i3.h"  // for IndirectStruct3
 #include "tests/cxx/iwyu_stricter_than_cpp-i4.h"  // for IndirectStruct4
-#include "tests/cxx/iwyu_stricter_than_cpp-type_alias.h"  // for DoesEverythingRightAl, DoesNotForwardDeclareAl, DoesNotForwardDeclareAndIncludesAl, DoesNotForwardDeclareProperlyAl, IncludesAl, IndirectStruct3NonProvidingAl, IndirectStruct4NonProvidingAl, TplDoesEverythingRightAgainAl, TplDoesEverythingRightAl, TplDoesNotForwardDeclareAl, TplDoesNotForwardDeclareAndIncludesAl, TplDoesNotForwardDeclareProperlyAl, TplIncludesAl
-#include "tests/cxx/iwyu_stricter_than_cpp-typedefs.h"  // for DoesEverythingRight, DoesNotForwardDeclare, DoesNotForwardDeclareAndIncludes, DoesNotForwardDeclareProperly, Includes, IndirectStruct3NonProvidingTypedef, IndirectStruct4NonProvidingTypedef, TplDoesEverythingRight, TplDoesEverythingRightAgain, TplDoesNotForwardDeclare, TplDoesNotForwardDeclareAndIncludes, TplDoesNotForwardDeclareProperly, TplIncludes
+#include "tests/cxx/iwyu_stricter_than_cpp-type_alias.h"  // for DoesEverythingRightAl, DoesNotForwardDeclareAl, DoesNotForwardDeclareAndIncludesAl, DoesNotForwardDeclareProperlyAl, IncludesAl, IncludesElaboratedAl, IndirectStruct3NonProvidingAl, IndirectStruct4NonProvidingAl, TplDoesEverythingRightAgainAl, TplDoesEverythingRightAl, TplDoesNotForwardDeclareAl, TplDoesNotForwardDeclareAndIncludesAl, TplDoesNotForwardDeclareProperlyAl, TplIncludesAl
+#include "tests/cxx/iwyu_stricter_than_cpp-typedefs.h"  // for DoesEverythingRight, DoesNotForwardDeclare, DoesNotForwardDeclareAndIncludes, DoesNotForwardDeclareProperly, Includes, IncludesElaborated, IndirectStruct3NonProvidingTypedef, IndirectStruct4NonProvidingTypedef, TplDoesEverythingRight, TplDoesEverythingRightAgain, TplDoesNotForwardDeclare, TplDoesNotForwardDeclareAndIncludes, TplDoesNotForwardDeclareProperly, TplIncludes
 struct DirectStruct1;
 struct DirectStruct2;
 struct IndirectStruct1;