Add ConstraintSystem#copy to minimize usages of ConstraintSystemImpl

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/Renderers.kt

@@ -249,7 +249,7 @@ public object Renderers {
     public fun renderUpperBoundViolatedInferenceError(
             inferenceErrorData: InferenceErrorData, result: TabledDescriptorRenderer
     ): TabledDescriptorRenderer {
-        val constraintSystem = inferenceErrorData.constraintSystem as ConstraintSystemImpl
+        val constraintSystem = inferenceErrorData.constraintSystem
         val status = constraintSystem.getStatus()
         LOG.assertTrue(status.hasViolatedUpperBound(),
                        renderDebugMessage("Upper bound violated renderer is applied for incorrect status", inferenceErrorData))

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

@@ -30,11 +30,11 @@ import org.jetbrains.kotlin.resolve.calls.checkers.CallChecker
 import org.jetbrains.kotlin.resolve.calls.context.BasicCallResolutionContext
 import org.jetbrains.kotlin.resolve.calls.context.CallCandidateResolutionContext
 import org.jetbrains.kotlin.resolve.calls.context.CheckArgumentTypesMode
+import org.jetbrains.kotlin.resolve.calls.inference.ConstraintSystem
 import org.jetbrains.kotlin.resolve.calls.inference.ConstraintSystemImpl
 import org.jetbrains.kotlin.resolve.calls.inference.InferenceErrorData
-import org.jetbrains.kotlin.resolve.calls.inference.constraintPosition.ConstraintPositionKind.EXPECTED_TYPE_POSITION
-import org.jetbrains.kotlin.resolve.calls.inference.constraintPosition.ConstraintPositionKind.FROM_COMPLETER
-import org.jetbrains.kotlin.resolve.calls.inference.constraintPosition.ConstraintPositionKind.TYPE_BOUND_POSITION
+import org.jetbrains.kotlin.resolve.calls.inference.constraintPosition.ConstraintPositionKind.*
+import org.jetbrains.kotlin.resolve.calls.inference.filterConstraintsOut
 import org.jetbrains.kotlin.resolve.calls.model.*
 import org.jetbrains.kotlin.resolve.calls.results.OverloadResolutionResultsImpl
 import org.jetbrains.kotlin.resolve.calls.results.ResolutionStatus
@@ -140,8 +140,8 @@ public class CallCompleter(
             expectedType: KotlinType,
             trace: BindingTrace
     ) {
-        fun updateSystemIfSuccessful(update: (ConstraintSystemImpl) -> Boolean) {
-            val copy = (getConstraintSystem() as ConstraintSystemImpl).copy() as ConstraintSystemImpl
+        fun updateSystemIfSuccessful(update: (ConstraintSystem) -> Boolean) {
+            val copy = constraintSystem!!.copy()
             if (update(copy)) {
                 setConstraintSystem(copy)
             }

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/inference/ConstraintSystem.kt

@@ -18,6 +18,8 @@ package org.jetbrains.kotlin.resolve.calls.inference
 
 import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
 import org.jetbrains.kotlin.resolve.calls.inference.constraintPosition.ConstraintPosition
+import org.jetbrains.kotlin.resolve.calls.inference.constraintPosition.ConstraintPositionKind
+import org.jetbrains.kotlin.resolve.calls.inference.constraintPosition.derivedFrom
 import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.types.TypeSubstitutor
 
@@ -84,4 +86,10 @@ public interface ConstraintSystem {
      * Returns the substitution only for type parameters that have result values, otherwise returns the type parameter itself.
      */
     public fun getPartialSubstitutor(): TypeSubstitutor
+
+    public fun copy(filterConstraintPosition: (ConstraintPosition) -> Boolean = { true }): ConstraintSystem
+}
+
+fun ConstraintSystem.filterConstraintsOut(excludePositionKind: ConstraintPositionKind): ConstraintSystem {
+    return copy { !it.derivedFrom(excludePositionKind) }
 }

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/inference/ConstraintSystemImpl.kt

@@ -177,15 +177,7 @@ public class ConstraintSystemImpl : ConstraintSystem {
         }.filterNotNull().filter { if (original) it in originalToVariables.keySet() else it in getAllTypeVariables() }
     }
 
-    public fun copy(): ConstraintSystem = createNewConstraintSystemFromThis { true }
-
-    public fun filterConstraintsOut(excludePositionKind: ConstraintPositionKind): ConstraintSystem {
-        return createNewConstraintSystemFromThis { !it.derivedFrom(excludePositionKind) }
-    }
-
-    private fun createNewConstraintSystemFromThis(
-            filterConstraintPosition: (ConstraintPosition) -> Boolean
-    ): ConstraintSystem {
+    override fun copy(filterConstraintPosition: (ConstraintPosition) -> Boolean): ConstraintSystem {
         val newSystem = ConstraintSystemImpl()
         for ((typeParameter, typeBounds) in allTypeParameterBounds) {
             newSystem.allTypeParameterBounds.put(typeParameter, typeBounds.filter(filterConstraintPosition))

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/tasks/AbstractTracingStrategy.java

@@ -30,7 +30,6 @@ import org.jetbrains.kotlin.resolve.BindingTrace;
 import org.jetbrains.kotlin.resolve.DescriptorUtils;
 import org.jetbrains.kotlin.resolve.calls.callUtil.CallUtilKt;
 import org.jetbrains.kotlin.resolve.calls.inference.ConstraintSystem;
-import org.jetbrains.kotlin.resolve.calls.inference.ConstraintSystemImpl;
 import org.jetbrains.kotlin.resolve.calls.inference.ConstraintSystemStatus;
 import org.jetbrains.kotlin.resolve.calls.inference.InferenceErrorData;
 import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall;
@@ -47,6 +46,7 @@ import java.util.Collection;
 import static org.jetbrains.kotlin.diagnostics.Errors.*;
 import static org.jetbrains.kotlin.resolve.BindingContext.AMBIGUOUS_REFERENCE_TARGET;
 import static org.jetbrains.kotlin.resolve.DescriptorUtils.getFqNameFromTopLevelClass;
+import static org.jetbrains.kotlin.resolve.calls.inference.ConstraintSystemKt.filterConstraintsOut;
 import static org.jetbrains.kotlin.resolve.calls.inference.constraintPosition.ConstraintPositionKind.EXPECTED_TYPE_POSITION;
 import static org.jetbrains.kotlin.types.TypeUtils.noExpectedType;
 
@@ -219,8 +219,7 @@ public abstract class AbstractTracingStrategy implements TracingStrategy {
             KotlinType declaredReturnType = data.descriptor.getReturnType();
             if (declaredReturnType == null) return;
 
-            ConstraintSystem systemWithoutExpectedTypeConstraint =
-                    ((ConstraintSystemImpl) constraintSystem).filterConstraintsOut(EXPECTED_TYPE_POSITION);
+            ConstraintSystem systemWithoutExpectedTypeConstraint = filterConstraintsOut(constraintSystem, EXPECTED_TYPE_POSITION);
             KotlinType substitutedReturnType = systemWithoutExpectedTypeConstraint.getResultingSubstitutor().substitute(
                     declaredReturnType, Variance.OUT_VARIANCE);
             assert substitutedReturnType != null; //todo

idea/src/org/jetbrains/kotlin/idea/quickfix/AddGenericUpperBoundFix.kt

@@ -29,10 +29,10 @@ import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.psi.KtPsiFactory
 import org.jetbrains.kotlin.psi.KtTypeParameter
 import org.jetbrains.kotlin.resolve.DescriptorToSourceUtils
-import org.jetbrains.kotlin.resolve.calls.inference.ConstraintSystemImpl
 import org.jetbrains.kotlin.resolve.calls.inference.ConstraintsUtil
 import org.jetbrains.kotlin.resolve.calls.inference.InferenceErrorData
 import org.jetbrains.kotlin.resolve.calls.inference.constraintPosition.ConstraintPositionKind
+import org.jetbrains.kotlin.resolve.calls.inference.filterConstraintsOut
 import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.types.Variance
 import org.jetbrains.kotlin.utils.singletonOrEmptyList
@@ -77,9 +77,7 @@ public class AddGenericUpperBoundFix(
         }
 
         private fun createActionsByInferenceData(inferenceData: InferenceErrorData): List<IntentionAction> {
-            val successfulConstraintSystem = (inferenceData.constraintSystem as? ConstraintSystemImpl)
-                                             ?.filterConstraintsOut(ConstraintPositionKind.TYPE_BOUND_POSITION)
-                                             ?: return emptyList()
+            val successfulConstraintSystem = inferenceData.constraintSystem.filterConstraintsOut(ConstraintPositionKind.TYPE_BOUND_POSITION)
 
             if (!successfulConstraintSystem.getStatus().isSuccessful()) return emptyList()