Fix coercion to Unit with equal Nothing constraint

#KT-39669 Fixed

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/components/PostponedArgumentsAnalyzer.kt

@@ -35,6 +35,7 @@ class PostponedArgumentsAnalyzer(
         fun canBeProper(type: KotlinTypeMarker): Boolean
 
         fun hasUpperOrEqualUnitConstraint(type: KotlinTypeMarker): Boolean
+        fun hasEqualNothingConstraint(type: KotlinTypeMarker): Boolean
 
         // mutable operations
         fun addOtherSystem(otherSystem: ConstraintStorage)
@@ -122,7 +123,7 @@ class PostponedArgumentsAnalyzer(
             c.canBeProper(rawReturnType) -> substitute(rawReturnType)
 
             // For Unit-coercion
-            c.hasUpperOrEqualUnitConstraint(rawReturnType) -> builtIns.unitType
+            c.hasUpperOrEqualUnitConstraint(rawReturnType) && !c.hasEqualNothingConstraint(rawReturnType) -> builtIns.unitType
 
             else -> null
         }

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/inference/model/NewConstraintSystemImpl.kt

@@ -386,9 +386,13 @@ class NewConstraintSystemImpl(
     // PostponedArgumentsAnalyzer.Context
     override fun hasUpperOrEqualUnitConstraint(type: KotlinTypeMarker): Boolean {
         checkState(State.BUILDING, State.COMPLETION, State.FREEZED)
-
         val constraints = storage.notFixedTypeVariables[type.typeConstructor()]?.constraints ?: return false
-
         return constraints.any { (it.kind == ConstraintKind.UPPER || it.kind == ConstraintKind.EQUALITY) && it.type.isUnit() }
     }
+
+    override fun hasEqualNothingConstraint(type: KotlinTypeMarker): Boolean {
+        checkState(State.BUILDING, State.COMPLETION, State.FREEZED)
+        val constraints = storage.notFixedTypeVariables[type.typeConstructor()]?.constraints ?: return false
+        return constraints.any { (it.kind == ConstraintKind.EQUALITY) && it.type.isNothing() }
+    }
 }