[tests] Add test data for KT-57709

compiler/testData/codegen/box/builderInference/issues/kt57709.kt

@@ -0,0 +1,43 @@
+// ISSUE: KT-57709
+// WITH_STDLIB
+
+// IGNORE_LIGHT_ANALYSIS
+// IGNORE_BACKEND: ANY
+// REASON: red code (see corresponding diagnostic test)
+
+var result = ""
+
+@JvmName("consumeAnyBuildeeReceiver")
+fun Buildee<Any>.consumeBuildeeReceiver() {
+    result += "Any/"
+}
+@JvmName("consumeDifferentTypeBuildeeReceiver")
+fun Buildee<DifferentType>.consumeBuildeeReceiver() {
+    result += "DifferentType/"
+}
+
+fun box(): String {
+    build<Any> {
+        setTypeVariable(Any())
+        consumeBuildeeReceiver()
+    }
+    build {
+        setTypeVariable(Any())
+        consumeBuildeeReceiver()
+    }
+    return if (result == "Any/Any/") "OK" else "FAIL: $result"
+}
+
+
+
+
+class DifferentType
+
+class Buildee<TV> {
+    fun setTypeVariable(value: TV) { storage = value }
+    private var storage: TV = Any() as TV
+}
+
+fun <PTV> build(instructions: Buildee<PTV>.() -> Unit): Buildee<PTV> {
+    return Buildee<PTV>().apply(instructions)
+}

compiler/testData/diagnostics/tests/builderInference/issues/kt57709.fir.kt

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+// ISSUE: KT-57709
+// CHECK_TYPE_WITH_EXACT
+// WITH_STDLIB
+
+fun test() {
+    val buildee = build {
+        setTypeVariable(Any())
+        <!OVERLOAD_RESOLUTION_AMBIGUITY!>consumeBuildeeReceiver<!>()
+    }
+    // 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<Any>>(buildee)
+}
+
+
+
+
+class DifferentType
+
+fun consumeAny(value: Any) {}
+
+fun consumeDifferentType(value: DifferentType) {}
+
+class Buildee<TV> {
+    fun setTypeVariable(value: TV) { storage = value }
+    fun getTypeVariable(): TV = storage
+    private var storage: TV = null!!
+}
+
+@JvmName("consumeAnyBuildeeReceiver")
+fun Buildee<Any>.consumeBuildeeReceiver() {
+    consumeAny(getTypeVariable())
+}
+@JvmName("consumeDifferentTypeBuildeeReceiver")
+fun Buildee<DifferentType>.consumeBuildeeReceiver() {
+    consumeDifferentType(getTypeVariable())
+}
+
+fun <PTV> build(instructions: Buildee<PTV>.() -> Unit): Buildee<PTV> {
+    return Buildee<PTV>().apply(instructions)
+}

compiler/testData/diagnostics/tests/builderInference/issues/kt57709.kt

@@ -0,0 +1,41 @@
+// ISSUE: KT-57709
+// CHECK_TYPE_WITH_EXACT
+// WITH_STDLIB
+
+fun test() {
+    val buildee = build {
+        setTypeVariable(Any())
+        <!STUB_TYPE_IN_RECEIVER_CAUSES_AMBIGUITY!><!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE, OVERLOAD_RESOLUTION_AMBIGUITY, OVERLOAD_RESOLUTION_AMBIGUITY_BECAUSE_OF_STUB_TYPES!>consumeBuildeeReceiver<!>()<!>
+    }
+    // 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<Any>>(buildee)
+}
+
+
+
+
+class DifferentType
+
+fun consumeAny(value: Any) {}
+
+fun consumeDifferentType(value: DifferentType) {}
+
+class Buildee<TV> {
+    fun setTypeVariable(value: TV) { storage = value }
+    fun getTypeVariable(): TV = storage
+    private var storage: TV = null!!
+}
+
+@JvmName("consumeAnyBuildeeReceiver")
+fun Buildee<Any>.consumeBuildeeReceiver() {
+    consumeAny(getTypeVariable())
+}
+@JvmName("consumeDifferentTypeBuildeeReceiver")
+fun Buildee<DifferentType>.consumeBuildeeReceiver() {
+    consumeDifferentType(getTypeVariable())
+}
+
+fun <PTV> build(instructions: Buildee<PTV>.() -> Unit): Buildee<PTV> {
+    return Buildee<PTV>().apply(instructions)
+}