KT-7433 Type inference pushes Unit inside generic function with lower bound constraint

#KT-7433 Fixed
 #KT-7351 Fixed

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/CallCompleter.kt

@@ -140,14 +140,6 @@ public class CallCompleter(
         val returnType = getCandidateDescriptor().getReturnType()
         if (returnType != null) {
             getConstraintSystem()!!.addSupertypeConstraint(expectedType, returnType, EXPECTED_TYPE_POSITION.position())
-
-            if (expectedType === TypeUtils.UNIT_EXPECTED_TYPE) {
-                updateSystemIfSuccessful {
-                    system ->
-                    system.addSupertypeConstraint(KotlinBuiltIns.getInstance().getUnitType(), returnType, EXPECTED_TYPE_POSITION.position())
-                    system.getStatus().isSuccessful()
-                }
-            }
         }
 
         val constraintSystemCompleter = trace[CONSTRAINT_SYSTEM_COMPLETER, getCall().getCalleeExpression()]
@@ -162,6 +154,14 @@ public class CallCompleter(
 
         (getConstraintSystem() as ConstraintSystemImpl).processDeclaredBoundConstraints()
 
+        if (returnType != null && expectedType === TypeUtils.UNIT_EXPECTED_TYPE) {
+            updateSystemIfSuccessful {
+                system ->
+                system.addSupertypeConstraint(KotlinBuiltIns.getInstance().getUnitType(), returnType, EXPECTED_TYPE_POSITION.position())
+                system.getStatus().isSuccessful()
+            }
+        }
+
         setResultingSubstitutor(getConstraintSystem()!!.getResultingSubstitutor())
     }
 

compiler/testData/diagnostics/tests/inference/constraints/kt7351ConstraintFromUnitExpectedType.kt

@@ -0,0 +1,19 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+package kt7351
+
+trait Node
+
+trait Source<T> {
+    fun f() : T
+}
+fun <T, S : Source<T>> S.woo() : T = this.f()
+
+fun Node.append(block : Source<Int>.() -> Unit) {
+}
+
+fun crashMe(node : Node) {
+    node.append {
+        woo()
+    }
+}

compiler/testData/diagnostics/tests/inference/constraints/kt7351ConstraintFromUnitExpectedType.txt

@@ -0,0 +1,20 @@
+package
+
+package kt7351 {
+    internal fun crashMe(/*0*/ node: kt7351.Node): kotlin.Unit
+    internal fun kt7351.Node.append(/*0*/ block: kt7351.Source<kotlin.Int>.() -> kotlin.Unit): kotlin.Unit
+    internal fun </*0*/ T, /*1*/ S : kt7351.Source<T>> S.woo(): T
+
+    internal trait Node {
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    internal trait Source</*0*/ T> {
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        internal abstract fun f(): T
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}

compiler/testData/diagnostics/tests/inference/constraints/kt7433.kt

@@ -0,0 +1,9 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER -UNUSED_VARIABLE
+
+public inline fun <S, T: S> Iterable<T>.reduce1(operation: (S, T) -> S): S = throw Exception()
+
+fun test(ints: List<Int>) {
+    val f: () -> Unit = {
+        ints.reduce1 { a, b -> a + b }
+    }
+}

compiler/testData/diagnostics/tests/inference/constraints/kt7433.txt

@@ -0,0 +1,4 @@
+package
+
+internal fun test(/*0*/ ints: kotlin.List<kotlin.Int>): kotlin.Unit
+kotlin.inline() public fun </*0*/ S, /*1*/ T : S> kotlin.Iterable<T>.reduce1(/*0*/ operation: (S, T) -> S): S

compiler/tests/org/jetbrains/kotlin/checkers/JetDiagnosticsTestGenerated.java

@@ -5834,6 +5834,18 @@ public class JetDiagnosticsTestGenerated extends AbstractJetDiagnosticsTest {
                     doTest(fileName);
                 }
 
+                @TestMetadata("kt7351ConstraintFromUnitExpectedType.kt")
+                public void testKt7351ConstraintFromUnitExpectedType() throws Exception {
+                    String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/inference/constraints/kt7351ConstraintFromUnitExpectedType.kt");
+                    doTest(fileName);
+                }
+
+                @TestMetadata("kt7433.kt")
+                public void testKt7433() throws Exception {
+                    String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/inference/constraints/kt7433.kt");
+                    doTest(fileName);
+                }
+
                 @TestMetadata("notNullConstraintOnNullableType.kt")
                 public void testNotNullConstraintOnNullableType() throws Exception {
                     String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/inference/constraints/notNullConstraintOnNullableType.kt");