[lldb] Add a test for calling open functions in expressions

See swiftlang/swift#80691

Author: adrian-prantl

lldb/test/API/lang/swift/expression/classes/open/Makefile

@@ -0,0 +1,3 @@
+SWIFT_SOURCES := main.swift
+
+include Makefile.rules

lldb/test/API/lang/swift/expression/classes/open/TestSwiftExpressionOpenClass.py

@@ -0,0 +1,15 @@
+import lldb
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test.decorators import *
+import lldbsuite.test.lldbutil as lldbutil
+
+class TestExpressionOpenClass(TestBase):
+    NO_DEBUG_INFO_TEST = True
+    @swiftTest
+    def test(self):
+        """Tests calling an open function"""
+        self.build()
+        lldbutil.run_to_source_breakpoint(
+            self, 'break here', lldb.SBFileSpec('main.swift'))
+
+        self.expect("expr -- a.foo()", substrs=["23"])

lldb/test/API/lang/swift/expression/classes/open/main.swift

@@ -0,0 +1,10 @@
+open class A {
+  open func foo() -> Int { return 23 }
+}
+
+func f() {
+  let a  = A()
+  print("break here \(a)")
+}
+
+f()