Add utility to check if effect is ESReturns

Somewhat simplify related code in AbstractBinaryFunctor and
AbstractUnaryFunctor

compiler/frontend/src/org/jetbrains/kotlin/contracts/EffectsExtractingVisitor.kt

@@ -125,7 +125,7 @@ class EffectsExtractingVisitor(
         // null bypassing function's contract, so we have to filter them out
 
         fun ESEffect.containsReturnsNull(): Boolean =
-            this == ESReturns(ESConstant.NULL) || this is ConditionalEffect && this.simpleEffect.containsReturnsNull()
+            isReturns { value == ESConstant.NULL } || this is ConditionalEffect && this.simpleEffect.containsReturnsNull()
 
         val effectsWithoutReturnsNull = computation.effects.filter { !it.containsReturnsNull() }
         return CallComputation(computation.type, effectsWithoutReturnsNull)

compiler/resolution/src/org/jetbrains/kotlin/contracts/model/functors/AbstractBinaryFunctor.kt

@@ -16,15 +16,15 @@
 
 package org.jetbrains.kotlin.contracts.model.functors
 
-import org.jetbrains.kotlin.contracts.model.structure.ESReturns
-import org.jetbrains.kotlin.contracts.model.structure.ESConstant
+import org.jetbrains.kotlin.contracts.model.Computation
 import org.jetbrains.kotlin.contracts.model.ConditionalEffect
 import org.jetbrains.kotlin.contracts.model.ESEffect
-import org.jetbrains.kotlin.contracts.model.Computation
+import org.jetbrains.kotlin.contracts.model.structure.ESConstant
+import org.jetbrains.kotlin.contracts.model.structure.isReturns
 
 abstract class AbstractBinaryFunctor : AbstractReducingFunctor() {
     override fun doInvocation(arguments: List<Computation>): List<ESEffect> {
-        assert(arguments.size == 2, { "Wrong size of arguments list for Binary functor: expected 2, got ${arguments.size}" })
+        assert(arguments.size == 2) { "Wrong size of arguments list for Binary functor: expected 2, got ${arguments.size}" }
         return invokeWithArguments(arguments[0], arguments[1])
     }
 
@@ -32,23 +32,13 @@ abstract class AbstractBinaryFunctor : AbstractReducingFunctor() {
         if (left is ESConstant) return invokeWithConstant(right, left)
         if (right is ESConstant) return invokeWithConstant(left, right)
 
-        val nonInterestingEffects = mutableListOf<ESEffect>()
-        val leftValueReturning = mutableListOf<ConditionalEffect>()
-        val rightValueReturning = mutableListOf<ConditionalEffect>()
+        val leftValueReturning =
+            left.effects.filterIsInstance<ConditionalEffect>().filter { it.simpleEffect.isReturns { value != ESConstant.WILDCARD } }
+        val rightValueReturning =
+            right.effects.filterIsInstance<ConditionalEffect>().filter { it.simpleEffect.isReturns { value != ESConstant.WILDCARD } }
 
-        left.effects.forEach {
-            if (it !is ConditionalEffect || it.simpleEffect !is ESReturns || it.simpleEffect.value == ESConstant.WILDCARD)
-                nonInterestingEffects += it
-            else
-                leftValueReturning += it
-        }
-
-        right.effects.forEach {
-            if (it !is ConditionalEffect || it.simpleEffect !is ESReturns || it.simpleEffect.value == ESConstant.WILDCARD)
-                nonInterestingEffects += it
-            else
-                rightValueReturning += it
-        }
+        val nonInterestingEffects =
+            left.effects - leftValueReturning + right.effects - rightValueReturning
 
         val evaluatedByFunctor = invokeWithReturningEffects(leftValueReturning, rightValueReturning)
 
@@ -60,4 +50,4 @@ abstract class AbstractBinaryFunctor : AbstractReducingFunctor() {
         left: List<ConditionalEffect>,
         right: List<ConditionalEffect>
     ): List<ConditionalEffect>
-}
+}

compiler/resolution/src/org/jetbrains/kotlin/contracts/model/functors/AbstractUnaryFunctor.kt

@@ -16,12 +16,11 @@
 
 package org.jetbrains.kotlin.contracts.model.functors
 
-import org.jetbrains.kotlin.contracts.model.structure.ESReturns
-import org.jetbrains.kotlin.contracts.model.structure.ESConstant
+import org.jetbrains.kotlin.contracts.model.Computation
 import org.jetbrains.kotlin.contracts.model.ConditionalEffect
 import org.jetbrains.kotlin.contracts.model.ESEffect
-import org.jetbrains.kotlin.contracts.model.Computation
-
+import org.jetbrains.kotlin.contracts.model.structure.ESConstant
+import org.jetbrains.kotlin.contracts.model.structure.isReturns
 
 /**
  * Unary functor that has sequential semantics, i.e. it won't apply to
@@ -32,15 +31,14 @@ import org.jetbrains.kotlin.contracts.model.Computation
  */
 abstract class AbstractUnaryFunctor : AbstractReducingFunctor() {
     override fun doInvocation(arguments: List<Computation>): List<ESEffect> {
-        assert(arguments.size == 1, { "Wrong size of arguments list for Unary operator: expected 1, got ${arguments.size}" })
+        assert(arguments.size == 1) { "Wrong size of arguments list for Unary operator: expected 1, got ${arguments.size}" }
         return invokeWithArguments(arguments[0])
     }
 
     fun invokeWithArguments(arg: Computation): List<ESEffect> {
-        val returning = mutableListOf<ConditionalEffect>()
-        val rest = mutableListOf<ESEffect>()
-
-        arg.effects.forEach { if (it !is ConditionalEffect || it.simpleEffect !is ESReturns || it.simpleEffect.value == ESConstant.WILDCARD) rest += it else returning += it }
+        val returning =
+            arg.effects.filterIsInstance<ConditionalEffect>().filter { it.simpleEffect.isReturns { value != ESConstant.WILDCARD } }
+        val rest = arg.effects - returning
 
         val evaluatedByFunctor = invokeWithReturningEffects(returning)
 
@@ -49,5 +47,3 @@ abstract class AbstractUnaryFunctor : AbstractReducingFunctor() {
 
     protected abstract fun invokeWithReturningEffects(list: List<ConditionalEffect>): List<ConditionalEffect>
 }
-
-

compiler/resolution/src/org/jetbrains/kotlin/contracts/model/structure/Effects.kt

@@ -44,4 +44,7 @@ data class ESReturns(val value: ESValue) : SimpleEffect() {
 
         return value == other.value
     }
-}
+}
+
+inline fun ESEffect.isReturns(block: ESReturns.() -> Boolean): Boolean =
+    this is ESReturns && block()