Fixed optimization in IterableTypesDetector which did not work from the beginning + make it work on FuzzyType

idea/src/org/jetbrains/kotlin/idea/completion/smart/SmartCompletion.kt

@@ -390,7 +390,7 @@ class SmartCompletion(
         val scope = bindingContext.get(BindingContext.RESOLUTION_SCOPE, expressionWithType)
         val iterableDetector = IterableTypesDetector(project, moduleDescriptor, scope, loopVarType)
 
-        return buildResultByTypeFilter(expressionWithType, receiver, Tail.RPARENTH) { iterableDetector.isIterable(it.type) }
+        return buildResultByTypeFilter(expressionWithType, receiver, Tail.RPARENTH) { iterableDetector.isIterable(it) }
     }
 
     private fun buildForInOperatorArgument(expressionWithType: JetExpression, receiver: JetExpression?): Result? {

idea/src/org/jetbrains/kotlin/idea/liveTemplates/macro/JetIterableVariableMacro.java

@@ -18,10 +18,14 @@ package org.jetbrains.kotlin.idea.liveTemplates.macro;
 
 import com.intellij.openapi.project.Project;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor;
 import org.jetbrains.kotlin.descriptors.VariableDescriptor;
 import org.jetbrains.kotlin.idea.JetBundle;
+import org.jetbrains.kotlin.idea.util.FuzzyType;
 import org.jetbrains.kotlin.idea.util.IterableTypesDetector;
 
+import java.util.Collections;
+
 public class JetIterableVariableMacro extends BaseJetVariableMacro {
 
     @Override
@@ -41,6 +45,6 @@ public class JetIterableVariableMacro extends BaseJetVariableMacro {
             @NotNull IterableTypesDetector iterableTypesDetector
     ) {
         //TODO: smart-casts
-        return iterableTypesDetector.isIterable(variableDescriptor.getType());
+        return iterableTypesDetector.isIterable(new FuzzyType(variableDescriptor.getType(), Collections.<TypeParameterDescriptor>emptyList()));
     }
 }

idea/src/org/jetbrains/kotlin/idea/util/IterableTypesDetector.kt

@@ -29,7 +29,6 @@ import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.resolve.scopes.JetScope
 import java.util.HashMap
 import org.jetbrains.kotlin.name.Name
-import org.jetbrains.kotlin.types.typeUtil.isSubtypeOf
 
 public class IterableTypesDetector(
         private val project: Project,
@@ -39,7 +38,7 @@ public class IterableTypesDetector(
 ) {
 
     private val injector = InjectorForMacros(project, moduleDescriptor)
-    private val cache = HashMap<JetType, Boolean>()
+    private val cache = HashMap<FuzzyType, Boolean>()
     private val iteratorName = Name.identifier("iterator")
 
     private val typesWithExtensionIterator: Collection<JetType> = scope.getFunctions(iteratorName)
@@ -47,23 +46,23 @@ public class IterableTypesDetector(
             .filterNotNull()
             .map { it.getType() }
 
-    public fun isIterable(type: JetType): Boolean {
+    public fun isIterable(type: FuzzyType): Boolean {
         return cache.getOrPut(type, { isIterableNoCache(type) })
     }
 
-    private fun isIterableNoCache(type: JetType): Boolean {
+    private fun isIterableNoCache(type: FuzzyType): Boolean {
         // optimization
         if (!canBeIterable(type)) return false
 
         val expression = JetPsiFactory(project).createExpression("fake")
-        val expressionReceiver = ExpressionReceiver(expression, type)
+        val expressionReceiver = ExpressionReceiver(expression, type.type)
         val context = ExpressionTypingContext.newContext(injector.getExpressionTypingServices(), BindingTraceContext(), scope, DataFlowInfo.EMPTY, TypeUtils.NO_EXPECTED_TYPE)
         val elementType = injector.getExpressionTypingComponents().getForLoopConventionsChecker().checkIterableConvention(expressionReceiver, context)
         if (elementType == null) return false
-        return loopVarType == null || elementType.isSubtypeOf(loopVarType)
+        return loopVarType == null || FuzzyType(elementType, type.freeParameters).checkIsSubtypeOf(loopVarType) != null
     }
 
-    private fun canBeIterable(type: JetType): Boolean {
+    private fun canBeIterable(type: FuzzyType): Boolean {
-        return type.getMemberScope().getFunctions(iteratorName).isEmpty() || typesWithExtensionIterator.any { type.isSubtypeOf(type) }
+        return type.type.getMemberScope().getFunctions(iteratorName).isNotEmpty() || typesWithExtensionIterator.any { type.checkIsSubtypeOf(it) != null }
     }
 }

idea/testData/completion/smart/forLoopRange/TypedLoopVar.kt

@@ -1,8 +1,13 @@
-fun foo(p1: Collection<String>, p2: Collection<Int>, p3: Collection<String?>) {
+trait X
-    for (i: Any in <caret>)
+trait Y: X
+trait Z
+
+fun foo(p1: Collection<X>, p2: Collection<Y>, p3: Collection<Z>, p4: Collection<X?>) {
+    for (i: X in <caret>)
 }
 
 // EXIST: p1
 // EXIST: p2
 // ABSENT: p3
+// ABSENT: p4
 // EXIST: { lookupString:"listOf", itemText: "listOf", tailText: "(vararg values: T) (kotlin)", typeText:"List<T>" }