[tests] Add test data for KT-53639

compiler/testData/diagnostics/tests/builderInference/issues/kt53639.fir.kt

@@ -0,0 +1,35 @@
+// ISSUE: KT-53639
+// CHECK_TYPE_WITH_EXACT
+
+fun test() {
+    val buildee = initializeAndBuild(
+        { build { setTypeVariable(TargetType()) } },
+        { placeholderExtensionInvokeOnBuildee() },
+    )
+    // 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<TargetType>>(buildee)
+}
+
+
+
+
+class TargetType
+
+class Buildee<TV> {
+    fun setTypeVariable(value: TV) { storage = value }
+    private var storage: TV = null!!
+}
+
+fun <ETV> Buildee<ETV>.placeholderExtensionInvokeOnBuildee() {}
+
+fun <PTV> build(instructions: Buildee<PTV>.() -> Unit): Buildee<PTV> {
+    return Buildee<PTV>().apply(instructions)
+}
+
+fun <PTV> initializeAndBuild(
+    initializer: () -> Buildee<PTV>,
+    instructions: Buildee<PTV>.() -> Unit
+): Buildee<PTV> {
+    return initializer().apply(instructions)
+}

compiler/testData/diagnostics/tests/builderInference/issues/kt53639.kt

@@ -0,0 +1,35 @@
+// ISSUE: KT-53639
+// CHECK_TYPE_WITH_EXACT
+
+fun test() {
+    val buildee = <!INFERRED_INTO_DECLARED_UPPER_BOUNDS!>initializeAndBuild<!>(
+        { build <!BUILDER_INFERENCE_MULTI_LAMBDA_RESTRICTION!>{ setTypeVariable(TargetType()) }<!> },
+        <!BUILDER_INFERENCE_MULTI_LAMBDA_RESTRICTION!>{ placeholderExtensionInvokeOnBuildee() }<!>,
+    )
+    // 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<TargetType>>(<!TYPE_MISMATCH("Buildee<TargetType>; Buildee<Any?>"), TYPE_MISMATCH("Buildee<Any?>; Buildee<TargetType>")!>buildee<!>)
+}
+
+
+
+
+class TargetType
+
+class Buildee<TV> {
+    fun setTypeVariable(value: TV) { storage = value }
+    private var storage: TV = null!!
+}
+
+fun <ETV> Buildee<ETV>.placeholderExtensionInvokeOnBuildee() {}
+
+fun <PTV> build(instructions: Buildee<PTV>.() -> Unit): Buildee<PTV> {
+    return Buildee<PTV>().apply(instructions)
+}
+
+fun <PTV> initializeAndBuild(
+    initializer: () -> Buildee<PTV>,
+    instructions: Buildee<PTV>.() -> Unit
+): Buildee<PTV> {
+    return initializer().apply(instructions)
+}