[lldb] Test compatibility between a class type from a member function expr and its original version

lldb/test/API/lang/cpp/this_class_type_mixing/Makefile

@@ -0,0 +1,3 @@
+CXX_SOURCES := main.cpp
+
+include Makefile.rules

lldb/test/API/lang/cpp/this_class_type_mixing/TestThisClassTypeMixing.py

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+"""
+Tests using a class type that originated from a member function evaluation
+with the same class type outside a member function.
+
+When evaluating expressions in a class, LLDB modifies the type of the current
+class by injecting a "$__lldb_expr" member function into the class. This
+function should not cause the type to become incompatible with its original
+definition without the "$__lldb_expr" member.
+"""
+
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+class TestCase(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    @no_debug_info_test
+    def test(self):
+        self.build()
+        lldbutil.run_to_source_breakpoint(self, "// break in member function",
+                                          lldb.SBFileSpec("main.cpp"))
+
+        # Evaluate an expression in a member function. Store the type of the
+        # 'this' pointer in a persistent variable.
+        self.expect_expr("A $p = *this; $p", result_type="A")
+
+        breakpoint = self.target().BreakpointCreateBySourceRegex(
+            "// break in main", lldb.SBFileSpec("main.cpp"))
+        self.assertNotEqual(breakpoint.GetNumResolvedLocations(), 0)
+        threads = lldbutil.continue_to_breakpoint(self.process(), breakpoint)
+        self.assertEqual(len(threads), 1)
+
+        # Evaluate expressions in the main function. Use the persistent type
+        # of "A" that came from an evaluation in a member function with a
+        # normal "A" type and make sure that LLDB can still evaluate
+        # expressions that reference both types at the same time.
+        self.expect_expr("$p.i + a.i", result_type="int", result_value="2")
+        self.expect_expr("a.i + $p.i", result_type="int", result_value="2")
+        self.expect_expr("a = $p; a.i", result_type="int", result_value="1")

lldb/test/API/lang/cpp/this_class_type_mixing/main.cpp

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+struct A {
+  int i = 1;
+  int member_method() {
+    return i; // break in member function
+  }
+};
+int main() {
+  A a;
+  int i = a.member_method();
+  return i; // break in main
+}