[clang] [clang][ASTImporter][test] Add test for importing explicit object parameter (PR #124305)

[Michael Buch via cfe-commits]

https://github.com/Michael137 updated https://github.com/llvm/llvm-project/pull/124305

>From 2fbabc9802e09a175bd71624b2ff89a2d9b7f3a1 Mon Sep 17 00:00:00 2001
From: Michael Buch <michaelbuch12 at gmail.com>
Date: Fri, 24 Jan 2025 11:59:42 +0000
Subject: [PATCH 1/3] [clang][ASTImporter][test] Add test for importing
 explicit object parameter

Adds test that confirms that we import the explicit object parameter location for `ParmVarDecl`s. This is how Clang determines whether a parameter `isExplicitObjectParamater`. The LLDB expression evaluator relies on this for calling "explicit object member functions".
---
 clang/unittests/AST/ASTImporterTest.cpp | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/clang/unittests/AST/ASTImporterTest.cpp b/clang/unittests/AST/ASTImporterTest.cpp
index 791248e7a394f1..153c2629fb3f99 100644
--- a/clang/unittests/AST/ASTImporterTest.cpp
+++ b/clang/unittests/AST/ASTImporterTest.cpp
@@ -3441,6 +3441,7 @@ TEST_P(ASTImporterOptionSpecificTestBase, ImportParmVarDecl) {
   ASSERT_TRUE(FromVar);
   ASSERT_TRUE(FromVar->hasUninstantiatedDefaultArg());
   ASSERT_TRUE(FromVar->getUninstantiatedDefaultArg());
+  ASSERT_FALSE(FromVar->isExplicitObjectParameter());
 
   const auto *ToVar = Import(FromVar, Lang_CXX11);
   EXPECT_TRUE(ToVar);
@@ -3448,6 +3449,25 @@ TEST_P(ASTImporterOptionSpecificTestBase, ImportParmVarDecl) {
   EXPECT_TRUE(ToVar->getUninstantiatedDefaultArg());
   EXPECT_NE(FromVar->getUninstantiatedDefaultArg(),
             ToVar->getUninstantiatedDefaultArg());
+  EXPECT_FALSE(ToVar->isExplicitObjectParameter());
+}
+
+TEST_P(ASTImporterOptionSpecificTestBase, ImportParmVarDecl_Explicit) {
+  const auto *Code = R"(
+    struct Wrapper {
+      void func(this Wrapper) {}
+    };
+    )";
+  Decl *FromTU = getTuDecl(Code, Lang_CXX23);
+  auto *FromVar = FirstDeclMatcher<ParmVarDecl>().match(FromTU, parmVarDecl());
+  ASSERT_TRUE(FromVar);
+  ASSERT_TRUE(FromVar->isExplicitObjectParameter());
+
+  const auto *ToVar = Import(FromVar, Lang_CXX23);
+  EXPECT_TRUE(ToVar);
+  EXPECT_TRUE(ToVar->isExplicitObjectParameter());
+  EXPECT_EQ(ToVar->getExplicitObjectParamThisLoc(),
+            FromVar->getExplicitObjectParamThisLoc());
 }
 
 TEST_P(ASTImporterOptionSpecificTestBase, ImportOfNonEquivalentField) {

>From 585c995b5f198592ffe23a51b39924fa183d2554 Mon Sep 17 00:00:00 2001
From: Michael Buch <michaelbuch12 at gmail.com>
Date: Mon, 27 Jan 2025 10:25:34 +0000
Subject: [PATCH 2/3] fixup! import SourceLocation instead of copying

---
 clang/lib/AST/ASTImporter.cpp           | 8 ++++++--
 clang/unittests/AST/ASTImporterTest.cpp | 2 +-
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index 0669aa1b809c34..7cd6e844893157 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -4701,9 +4701,13 @@ ExpectedDecl ASTNodeImporter::VisitImplicitParamDecl(ImplicitParamDecl *D) {
 
 Error ASTNodeImporter::ImportDefaultArgOfParmVarDecl(
     const ParmVarDecl *FromParam, ParmVarDecl *ToParam) {
+  
+  auto LocOrErr = import(FromParam->getExplicitObjectParamThisLoc());
+  if (!LocOrErr)
+    return LocOrErr.takeError();
+
+  ToParam->setExplicitObjectParameterLoc(*LocOrErr);
   ToParam->setHasInheritedDefaultArg(FromParam->hasInheritedDefaultArg());
-  ToParam->setExplicitObjectParameterLoc(
-      FromParam->getExplicitObjectParamThisLoc());
   ToParam->setKNRPromoted(FromParam->isKNRPromoted());
 
   if (FromParam->hasUninstantiatedDefaultArg()) {
diff --git a/clang/unittests/AST/ASTImporterTest.cpp b/clang/unittests/AST/ASTImporterTest.cpp
index 153c2629fb3f99..e77860521335ed 100644
--- a/clang/unittests/AST/ASTImporterTest.cpp
+++ b/clang/unittests/AST/ASTImporterTest.cpp
@@ -3466,7 +3466,7 @@ TEST_P(ASTImporterOptionSpecificTestBase, ImportParmVarDecl_Explicit) {
   const auto *ToVar = Import(FromVar, Lang_CXX23);
   EXPECT_TRUE(ToVar);
   EXPECT_TRUE(ToVar->isExplicitObjectParameter());
-  EXPECT_EQ(ToVar->getExplicitObjectParamThisLoc(),
+  EXPECT_NE(ToVar->getExplicitObjectParamThisLoc(),
             FromVar->getExplicitObjectParamThisLoc());
 }
 

>From c89237c2e08e471644898a362be960513bb5f1fe Mon Sep 17 00:00:00 2001
From: Michael Buch <michaelbuch12 at gmail.com>
Date: Mon, 27 Jan 2025 10:31:33 +0000
Subject: [PATCH 3/3] fixup! clang-format

---
 clang/lib/AST/ASTImporter.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index 7cd6e844893157..4dfac1bb845fe1 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -4701,7 +4701,7 @@ ExpectedDecl ASTNodeImporter::VisitImplicitParamDecl(ImplicitParamDecl *D) {
 
 Error ASTNodeImporter::ImportDefaultArgOfParmVarDecl(
     const ParmVarDecl *FromParam, ParmVarDecl *ToParam) {
-  
+
   auto LocOrErr = import(FromParam->getExplicitObjectParamThisLoc());
   if (!LocOrErr)
     return LocOrErr.takeError();