From f9f4fd2eef993ed063f0ac181623023ec7350c7f Mon Sep 17 00:00:00 2001
From: Bolshakov <bolsh.andrey@yandex.ru>
Date: Tue, 24 Jan 2023 22:04:05 +0300
Subject: [PATCH] Test reporting types hidden in tpl arguments

The full type use reporting in the three covered cases is ensured
with excessive `CanIgnoreType` calls which check not only the type
to be reported but also the type before dereferencing (which occurs
to be in the resugaring map). This approach should be refactored
in subsequent commits.
---
 tests/cxx/member_expr.cc      | 22 ++++++++++++++++++++++
 tests/cxx/operator_new.cc     | 11 +++++++++++
 tests/cxx/sizeof_reference.cc | 16 ++++++++++++++++
 3 files changed, 49 insertions(+)

diff --git a/tests/cxx/member_expr.cc b/tests/cxx/member_expr.cc
index 0ec420a..3584275 100644
--- a/tests/cxx/member_expr.cc
+++ b/tests/cxx/member_expr.cc
@@ -120,6 +120,27 @@ void ViaMacro(const IndirectTemplate<IndirectClass>& ic) {
   IC_CALL_METHOD;
 }
 
+// Test type use with member expression inside a template.
+
+template <typename T>
+void MemberExprInside() {
+  T* t = nullptr;
+  (*t)->Method();
+}
+
+class IndirectClass;  // IndirectClassPtr doesn't provide IndirectClass.
+typedef IndirectClass* IndirectClassPtr;
+
+namespace ns {
+using ::IndirectClassPtr;
+}
+
+void Fn() {
+  // IndirectClass is hidden by a pointer and (at least) two levels of sugar.
+  // IWYU: IndirectClass is...*indirect.h
+  MemberExprInside<ns::IndirectClassPtr>();
+}
+
 /**** IWYU_SUMMARY
 
 tests/cxx/member_expr.cc should add these lines:
@@ -127,6 +148,7 @@ tests/cxx/member_expr.cc should add these lines:
 
 tests/cxx/member_expr.cc should remove these lines:
 - #include "tests/cxx/direct.h"  // lines XX-XX
+- class IndirectClass;  // lines XX-XX
 
 The full include-list for tests/cxx/member_expr.cc:
 #include "tests/cxx/indirect.h"  // for IndirectClass, IndirectTemplate
diff --git a/tests/cxx/operator_new.cc b/tests/cxx/operator_new.cc
index fb90556..4523f2f 100644
--- a/tests/cxx/operator_new.cc
+++ b/tests/cxx/operator_new.cc
@@ -43,6 +43,12 @@ void ExpressionsBuiltinTypes() {
 }
 
 // New- and delete-expressions with user-defined types.
+
+template <typename T>
+void TplFnWithDelete(T p) {
+  delete p;
+}
+
 void ExpressionsUserTypes() {
   // IWYU: IndirectClass needs a declaration
   // IWYU: IndirectClass is...*indirect.h
@@ -55,6 +61,11 @@ void ExpressionsUserTypes() {
   IndirectClass* arr = new IndirectClass[4];
   // IWYU: IndirectClass is...*indirect.h
   delete[] arr;
+
+  // Hide the pointer type behind "decltype" sugar.
+  decltype(elem) elem2 = nullptr;
+  // IWYU: IndirectClass is...*indirect.h
+  TplFnWithDelete(elem2);
 }
 
 // Aligned allocation uses operator new(size_t, std::align_val_t) under the
diff --git a/tests/cxx/sizeof_reference.cc b/tests/cxx/sizeof_reference.cc
index fe5256c..99e42a0 100644
--- a/tests/cxx/sizeof_reference.cc
+++ b/tests/cxx/sizeof_reference.cc
@@ -103,6 +103,22 @@ SizeofTakingStructTplRef2<IndirectClass> sizeof_taking_struct5;
 // IWYU: IndirectClass needs a declaration
 SizeofTakingStructTplRef2<IndirectClass&> sizeof_taking_struct6;
 
+// The same with some sugar.
+
+// IWYU: IndirectClass is...*indirect.h
+SizeofTakingStruct<decltype(ref)> sizeof_taking_struct7;
+
+// IWYU: IndirectClass is...*indirect.h
+SizeofTakingStructRef<decltype(dummy)> sizeof_taking_struct8;
+
+SizeofTakingStructTpl<decltype(ref)> sizeof_taking_struct9;
+
+SizeofTakingStructTplRef<decltype(dummy)> sizeof_taking_struct10;
+
+// IWYU: IndirectClass is...*indirect.h
+SizeofTakingStructTplRef2<decltype(dummy)> sizeof_taking_struct11;
+
+SizeofTakingStructTplRef2<decltype(ref)> sizeof_taking_struct12;
 
 /**** IWYU_SUMMARY