[tests] BI (1P&1TV/1TIO): add tests for contexts of source-sink feeds

single builder parameter
single postponed type variable
single origin of type information

relevant issues:
KT-60274
KT-60663

compiler/testData/diagnostics/tests/builderInference/oneParameter/oneTypeVariable/oneTypeInfoOrigin/sourceSinkFeedContexts/InsideNestedBuilderInferenceLambda.fir.kt

@@ -0,0 +1,59 @@
+// DIAGNOSTICS: -UNCHECKED_CAST
+
+// CHECK_TYPE_WITH_EXACT
+
+// ISSUE: KT-60663
+/* ATTENTION:
+ * this test is supposed to monitor unclear feature behavior;
+ * an explicit design decision regarding said behavior has not been made at the moment of test creation;
+ * if the behavior of the test changes, please consult with the linked YT ticket
+ * and either add a comment about the change if an explicit design decision is still unavailable
+ * (preferably accompanied by an analysis of the change's reasons)
+ * or remove this disclaimer otherwise
+ */
+
+class Buildee<CT> {
+    fun yield(arg: CT) {}
+    fun materialize(): CT = UserKlass() as CT
+}
+
+fun <FT> build(
+    instructions: Buildee<FT>.() -> Unit
+): Buildee<FT> {
+    return Buildee<FT>().apply(instructions)
+}
+
+class UserKlass
+
+class NestedBuildee<T> {
+    fun nestedYield(arg: T) {}
+}
+fun <T> nestedBuild(
+    instructions: NestedBuildee<T>.() -> Unit
+): NestedBuildee<T> {
+    return NestedBuildee<T>().apply(instructions)
+}
+
+// test 1: PTV is in consuming position (yield-case)
+fun testYield() {
+    val arg: UserKlass = UserKlass()
+    val buildee = <!NEW_INFERENCE_NO_INFORMATION_FOR_PARAMETER!>build<!> {
+        nestedBuild {
+            yield(arg)
+            nestedYield(42)
+        }
+    }
+    <!NEW_INFERENCE_NO_INFORMATION_FOR_PARAMETER!>checkExactType<!><<!CANNOT_INFER_PARAMETER_TYPE!>Buildee<UserKlass><!>>(buildee)
+}
+
+// test 2: PTV is in producing position (materialize-case)
+fun testMaterialize() {
+    fun consume(arg: UserKlass) {}
+    val buildee = <!NEW_INFERENCE_NO_INFORMATION_FOR_PARAMETER!>build<!> {
+        nestedBuild {
+            consume(materialize())
+            nestedYield(42)
+        }
+    }
+    <!NEW_INFERENCE_NO_INFORMATION_FOR_PARAMETER!>checkExactType<!><<!CANNOT_INFER_PARAMETER_TYPE!>Buildee<UserKlass><!>>(buildee)
+}

compiler/testData/diagnostics/tests/builderInference/oneParameter/oneTypeVariable/oneTypeInfoOrigin/sourceSinkFeedContexts/InsideNestedBuilderInferenceLambda.kt

@@ -0,0 +1,59 @@
+// DIAGNOSTICS: -UNCHECKED_CAST
+
+// CHECK_TYPE_WITH_EXACT
+
+// ISSUE: KT-60663
+/* ATTENTION:
+ * this test is supposed to monitor unclear feature behavior;
+ * an explicit design decision regarding said behavior has not been made at the moment of test creation;
+ * if the behavior of the test changes, please consult with the linked YT ticket
+ * and either add a comment about the change if an explicit design decision is still unavailable
+ * (preferably accompanied by an analysis of the change's reasons)
+ * or remove this disclaimer otherwise
+ */
+
+class Buildee<CT> {
+    fun yield(arg: CT) {}
+    fun materialize(): CT = UserKlass() as CT
+}
+
+fun <FT> build(
+    instructions: Buildee<FT>.() -> Unit
+): Buildee<FT> {
+    return Buildee<FT>().apply(instructions)
+}
+
+class UserKlass
+
+class NestedBuildee<T> {
+    fun nestedYield(arg: T) {}
+}
+fun <T> nestedBuild(
+    instructions: NestedBuildee<T>.() -> Unit
+): NestedBuildee<T> {
+    return NestedBuildee<T>().apply(instructions)
+}
+
+// test 1: PTV is in consuming position (yield-case)
+fun testYield() {
+    val arg: UserKlass = UserKlass()
+    val buildee = <!NEW_INFERENCE_NO_INFORMATION_FOR_PARAMETER!>build<!> {
+        nestedBuild {
+            yield(arg)
+            nestedYield(42)
+        }
+    }
+    checkExactType<Buildee<UserKlass>>(<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>buildee<!>)
+}
+
+// test 2: PTV is in producing position (materialize-case)
+fun testMaterialize() {
+    fun consume(arg: UserKlass) {}
+    val buildee = <!NEW_INFERENCE_NO_INFORMATION_FOR_PARAMETER!>build<!> {
+        nestedBuild {
+            consume(materialize())
+            nestedYield(42)
+        }
+    }
+    checkExactType<Buildee<UserKlass>>(<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>buildee<!>)
+}

compiler/testData/diagnostics/tests/builderInference/oneParameter/oneTypeVariable/oneTypeInfoOrigin/sourceSinkFeedContexts/ThroughDelegatedLocalVariableMaterializeCase.kt

@@ -0,0 +1,34 @@
+// FIR_IDENTICAL
+// DIAGNOSTICS: -UNCHECKED_CAST
+
+// CHECK_TYPE_WITH_EXACT
+
+// ISSUE: KT-60274
+// (also see an analogous codegen test)
+
+import kotlin.reflect.KProperty
+
+class Buildee<CT> {
+    fun materialize(): CT = UserKlass() as CT
+}
+
+fun <FT> build(
+    instructions: Buildee<FT>.() -> Unit
+): Buildee<FT> {
+    return Buildee<FT>().apply(instructions)
+}
+
+class UserKlass
+
+class Delegate<T>(private val value: T) {
+    operator fun getValue(reference: Nothing?, property: KProperty<*>): T = value
+}
+
+fun testMaterialize() {
+    fun consume(arg: UserKlass) {}
+    val buildee = build {
+        val temp by Delegate(materialize())
+        consume(temp)
+    }
+    checkExactType<Buildee<UserKlass>>(buildee)
+}