[tests] Add test data for KT-52838

compiler/testData/diagnostics/tests/builderInference/issues/kt52838b.kt

@@ -0,0 +1,27 @@
+// ISSUE: KT-52838
+// CHECK_TYPE_WITH_EXACT
+
+fun test() {
+    val buildee = build {
+        this as DerivedBuildee<*>
+        getTypeVariable()
+        <!RECEIVER_TYPE_MISMATCH("CapturedType(*); CapturedType(*)"), RECEIVER_TYPE_MISMATCH("CapturedType(*); CapturedType(*)")!>getTypeVariable<!>()
+    }
+    // exact type equality check — turns unexpected compile-time behavior into red code
+    // considered to be non-user-reproducible code for the purposes of these tests
+    checkExactType<Buildee<*>>(<!TYPE_MISMATCH("Buildee<Any?>; Buildee<*>")!>buildee<!>)
+}
+
+
+
+
+open class Buildee<TV> {
+    fun getTypeVariable(): TV = storage
+    private var storage: TV = null!!
+}
+
+class DerivedBuildee<TA>: Buildee<TA>()
+
+fun <PTV> build(instructions: Buildee<PTV>.() -> Unit): Buildee<PTV> {
+    return DerivedBuildee<PTV>().apply(instructions)
+}