Analyze aliased component types

This brings several improvements: - avoiding erroneous consideration of aliased component types as provided just because their forward declaration is in the other (internal alias declaring) file; - avoiding erroneous consideration of aliased template arguments as provided due to a nested type alias; - correct handling of aliased types in contexts other than direct aliased type usage (e. g. when handling function return type); - recursive handling of nested alias templates similar to `typedef`s; - avoiding of losing nested `typedef` internals during recursive collecting their provided types, like `Class` inside such an elaborated alias: `using AliasedClass = Identity<Class>::Alias;`.
bolshakov-a · Feb 4, 2024 · 1f53a15 · 1f53a15
1 parent d3d5a6a
commit 1f53a15
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Showing 11 changed files with 132 additions and 18 deletions.
diff --git a/iwyu.cc b/iwyu.cc
@@ -1450,20 +1450,6 @@ class IwyuBaseAstVisitor : public BaseAstVisitor<Derived> {
 
   set<const Type*> GetProvidedTypesForAlias(const Type* underlying_type,
                                             SourceLocation decl_loc) const {
-    // If the underlying type is itself a typedef, we recurse.
-    if (const auto* underlying_typedef =
-            underlying_type->getAs<TypedefType>()) {
-      if (const auto* underlying_typedef_decl = dyn_cast<TypedefNameDecl>(TypeToDeclAsWritten(underlying_typedef))) {
-        // TODO(csilvers): if one of the intermediate typedefs
-        // #includes the necessary definition of the 'final'
-        // underlying type, do we want to return it here?
-        return GetProvidedTypesForAlias(
-            underlying_typedef_decl->getUnderlyingType().getTypePtr(),
-            GetLocation(underlying_typedef_decl));
-      }
-    }
-    // TODO(bolshakov): handle underlying alias templates.
-
     return GetProvidedTypes(underlying_type, decl_loc);
   }
 
@@ -2609,8 +2595,31 @@ class IwyuBaseAstVisitor : public BaseAstVisitor<Derived> {
                                     SourceLocation loc) const {
     set<const Type*> retval;
     for (const Type* component : GetComponentsOfTypeWithoutSubstituted(type)) {
-      if (!CodeAuthorWantsJustAForwardDeclare(component, loc))
-        retval.insert(component);
+      // TODO(csilvers): if one of the intermediate typedefs
+      // #includes the necessary definition of the 'final'
+      // underlying type, do we want to return it here?
+      if (const auto* typedef_type = dyn_cast<TypedefType>(component)) {
+        InsertAllInto(
+            GetProvidedTypesForAlias(typedef_type->desugar().getTypePtr(),
+                                     GetLocation(typedef_type->getDecl())),
+            &retval);
+        continue;
+      }
+      if (const auto* tpl_spec_type =
+              dyn_cast<TemplateSpecializationType>(component)) {
+        const NamedDecl* decl = TypeToDeclAsWritten(tpl_spec_type);
+        if (const auto* al_tpl_decl = dyn_cast<TypeAliasTemplateDecl>(decl)) {
+          const TypeAliasDecl* al_decl = al_tpl_decl->getTemplatedDecl();
+          InsertAllInto(
+              GetProvidedTypesForAlias(tpl_spec_type->desugar().getTypePtr(),
+                                       GetLocation(al_decl)),
+              &retval);
+          continue;
+        }
+      }
+      const Type* canonical = GetCanonicalType(component);
+      if (!CodeAuthorWantsJustAForwardDeclare(canonical, loc))
+        retval.insert(canonical);
     }
     return retval;
   }

diff --git a/iwyu_ast_util.cc b/iwyu_ast_util.cc
@@ -686,7 +686,7 @@ class TypeEnumeratorWithoutSubstituted
     if (IsSubstTemplateTypeParmType(type))
       return true;
 
-    seen_types_.insert(GetCanonicalType(type));
+    seen_types_.insert(Desugar(type));
 
     return Base::TraverseType(qual_type);
   }

diff --git a/tests/cxx/iwyu_stricter_than_cpp-d5.h b/tests/cxx/iwyu_stricter_than_cpp-d5.h
@@ -0,0 +1,14 @@
+//===--- iwyu_stricter_than_cpp-d5.h - test input file for iwyu -----------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "iwyu_stricter_than_cpp-i4.h"
+
+// No forward-declaration of 'IndirectClass' here.
+
+IndirectStruct4::IndirectClassNonProvidingTypedef RetNonProvidingTypedef();
diff --git a/tests/cxx/iwyu_stricter_than_cpp-i4.h b/tests/cxx/iwyu_stricter_than_cpp-i4.h
@@ -7,10 +7,15 @@
 //
 //===----------------------------------------------------------------------===//
 
+#ifndef IWYU_STRICTER_THAN_CPP_I4_H_
+#define IWYU_STRICTER_THAN_CPP_I4_H_
+
 class IndirectClass;
 
 struct IndirectStruct4 {
   typedef IndirectClass IndirectClassNonProvidingTypedef;
 
   using IndirectClassNonProvidingAl = IndirectClass;
 };
+
+#endif  // IWYU_STRICTER_THAN_CPP_I4_H_
diff --git a/tests/cxx/iwyu_stricter_than_cpp.cc b/tests/cxx/iwyu_stricter_than_cpp.cc
@@ -48,6 +48,7 @@
 #include "tests/cxx/iwyu_stricter_than_cpp-autocast2.h"
 #include "tests/cxx/iwyu_stricter_than_cpp-d2.h"
 #include "tests/cxx/iwyu_stricter_than_cpp-d3.h"
+#include "tests/cxx/iwyu_stricter_than_cpp-d5.h"
 
 template <typename T>
 void UsingFn() {
@@ -449,6 +450,9 @@ void TestFunctionReturn() {
   using Alias = TplIndirectStruct3<IndirectStruct2, IndirectStruct2>;
 
   Call<Alias, TplAllForwardDeclaredFn>();
+
+  // IWYU: IndirectClass is...*indirect.h
+  RetNonProvidingTypedef();
 }
 
 void TestDefaultTplArgs() {
@@ -493,6 +497,7 @@ The full include-list for tests/cxx/iwyu_stricter_than_cpp.cc:
 #include "tests/cxx/indirect.h"  // for IndirectClass
 #include "tests/cxx/iwyu_stricter_than_cpp-autocast.h"  // for FnRefs, FnValues, HeaderDefinedFnRefs, HeaderDefinedTplFnRefs, TplFnRefs, TplFnValues
 #include "tests/cxx/iwyu_stricter_than_cpp-d3.h"  // for IndirectStruct3ProvidingAl, IndirectStruct3ProvidingTypedef, IndirectStruct4ProvidingAl, IndirectStruct4ProvidingTypedef
+#include "tests/cxx/iwyu_stricter_than_cpp-d5.h"  // for RetNonProvidingTypedef
 #include "tests/cxx/iwyu_stricter_than_cpp-def_tpl_arg.h"  // for TplWithDefaultArgs
 #include "tests/cxx/iwyu_stricter_than_cpp-fnreturn.h"  // for DoesEverythingRightFn, DoesNotForwardDeclareAndIncludesFn, DoesNotForwardDeclareFn, DoesNotForwardDeclareProperlyFn, IncludesFn, TplAllForwardDeclaredFn, TplAllNeededTypesProvidedFn, TplDoesEverythingRightAgainFn, TplDoesEverythingRightFn, TplDoesNotForwardDeclareAndIncludesFn, TplDoesNotForwardDeclareFn, TplDoesNotForwardDeclareProperlyFn, TplIncludesFn, TplOnlyArgumentTypeProvidedFn, TplOnlyTemplateProvidedFn
 #include "tests/cxx/iwyu_stricter_than_cpp-i2.h"  // for IndirectStruct2, TplIndirectStruct2

diff --git a/tests/cxx/typedef_chain_in_template-d5.h b/tests/cxx/typedef_chain_in_template-d5.h
@@ -0,0 +1,30 @@
+//===--- typedef_chain_in_template-d5.h - test input file for iwyu --------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "tests/cxx/typedef_chain_in_template-i1.h"
+#include "tests/cxx/typedef_chain_in_template-i2.h"
+
+template <typename T>
+struct IdentityStructComplex {
+  using Type = typename TypedefWrapper<T>::value_type;
+};
+
+template <typename T>
+using IdentityAlias = T;
+
+template <typename T>
+using IdentityAliasComplex = IdentityAlias<T>;
+
+template <typename T>
+struct Tpl {
+  static constexpr auto s = sizeof(T);
+};
+
+using TplWithNonProvidedAliased1 = Tpl<NonProvidingAlias>;
+using TplWithNonProvidedAliased2 = Tpl<NonProvidingAliasTpl<1>>;
diff --git a/tests/cxx/typedef_chain_in_template-i1.h b/tests/cxx/typedef_chain_in_template-i1.h
@@ -9,8 +9,13 @@
 
 // This header mimics ext/alloc_traits.h in libstdc++.
 
+#ifndef TYPEDEF_CHAIN_IN_TEMPLATE_I1_H_
+#define TYPEDEF_CHAIN_IN_TEMPLATE_I1_H_
+
 template<typename T>
 struct TypedefWrapper {
   typedef T value_type;
   typedef value_type& reference;
 };
+
+#endif  // TYPEDEF_CHAIN_IN_TEMPLATE_I1_H_
diff --git a/tests/cxx/typedef_chain_in_template-i2.h b/tests/cxx/typedef_chain_in_template-i2.h
@@ -0,0 +1,15 @@
+//===--- typedef_chain_in_template-i2.h - test input file for iwyu --------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+class TypedefChainClass;
+
+using NonProvidingAlias = TypedefChainClass;
+
+template <int>
+using NonProvidingAliasTpl = TypedefChainClass;
diff --git a/tests/cxx/typedef_chain_in_template.cc b/tests/cxx/typedef_chain_in_template.cc
@@ -19,6 +19,7 @@
 #include "tests/cxx/typedef_chain_in_template-d2.h"
 #include "tests/cxx/typedef_chain_in_template-d3.h"
 #include "tests/cxx/typedef_chain_in_template-d4.h"
+#include "tests/cxx/typedef_chain_in_template-d5.h"
 
 void UsageAsWithLibstdcpp() {
   // IWYU: TypedefChainClass needs a declaration
@@ -56,6 +57,25 @@ void UsageWithLongerTypedefChain() {
   c.GetContent2().Method();
 }
 
+void Fn() {
+  // IWYU: TypedefChainClass needs a declaration
+  // IWYU: TypedefChainClass is...*typedef_chain_class.h
+  IdentityStructComplex<TypedefChainClass>::Type isc;
+  // IWYU: TypedefChainClass is...*typedef_chain_class.h
+  isc.Method();
+
+  // IWYU: TypedefChainClass needs a declaration
+  // IWYU: TypedefChainClass is...*typedef_chain_class.h
+  IdentityAliasComplex<TypedefChainClass> iac;
+  // IWYU: TypedefChainClass is...*typedef_chain_class.h
+  iac.Method();
+
+  // IWYU: TypedefChainClass is...*typedef_chain_class.h
+  (void)sizeof(TplWithNonProvidedAliased1);
+  // IWYU: TypedefChainClass is...*typedef_chain_class.h
+  (void)sizeof(TplWithNonProvidedAliased2);
+}
+
 /**** IWYU_SUMMARY
 
 tests/cxx/typedef_chain_in_template.cc should add these lines:
@@ -69,5 +89,6 @@ The full include-list for tests/cxx/typedef_chain_in_template.cc:
 #include "tests/cxx/typedef_chain_in_template-d2.h"  // for ContainerAsLibcpp
 #include "tests/cxx/typedef_chain_in_template-d3.h"  // for ContainerShortTypedefChain
 #include "tests/cxx/typedef_chain_in_template-d4.h"  // for ContainerLongTypedefChain
+#include "tests/cxx/typedef_chain_in_template-d5.h"  // for IdentityAliasComplex, IdentityStructComplex, TplWithNonProvidedAliased1, TplWithNonProvidedAliased2
 
 ***** IWYU_SUMMARY */
diff --git a/tests/cxx/typedef_chain_no_follow-d4.h b/tests/cxx/typedef_chain_no_follow-d4.h
@@ -13,3 +13,10 @@ template <typename T>
 using IdentityAlias = T;
 
 using ProvidingWithAliasTpl = IdentityAlias<TypedefChainClass>;
+
+template <typename T>
+struct IdentityStruct {
+  using Type = T;
+};
+
+using ProvidingWithStructTpl = IdentityStruct<TypedefChainClass>::Type;
diff --git a/tests/cxx/typedef_chain_no_follow.cc b/tests/cxx/typedef_chain_no_follow.cc
@@ -26,6 +26,9 @@ void TypedefDeclaredInGlobalNamespace() {
 
   ProvidingWithAliasTpl pwat;
   pwat.Method();
+
+  ProvidingWithStructTpl pwst;
+  pwst.Method();
 }
 
 // Tests how we handle a typedef declared in a class.  Main purpose is to make
@@ -54,6 +57,6 @@ The full include-list for tests/cxx/typedef_chain_no_follow.cc:
 #include "tests/cxx/typedef_chain_no_follow-d1.h"  // for TypedefChainTypedef
 #include "tests/cxx/typedef_chain_no_follow-d2.h"  // for NonContainer1
 #include "tests/cxx/typedef_chain_no_follow-d3.h"  // for NonContainer2
-#include "tests/cxx/typedef_chain_no_follow-d4.h"  // for ProvidingWithAliasTpl
+#include "tests/cxx/typedef_chain_no_follow-d4.h"  // for ProvidingWithAliasTpl, ProvidingWithStructTpl
 
 ***** IWYU_SUMMARY */