[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] [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) {