Fixed 'subtype' for captured type

core/descriptors/src/org/jetbrains/jet/lang/resolve/calls/inference/CapturedTypeConstructor.kt

@@ -22,9 +22,14 @@ import org.jetbrains.jet.lang.types.TypeConstructor
 import org.jetbrains.jet.lang.descriptors.TypeParameterDescriptor
 import org.jetbrains.jet.lang.descriptors.annotations.Annotations
 import org.jetbrains.jet.lang.types.Variance
+import org.jetbrains.jet.lang.types.Variance.*
 import org.jetbrains.jet.lang.types.lang.KotlinBuiltIns
-import org.jetbrains.jet.lang.types.JetTypeImpl
 import org.jetbrains.jet.lang.types.ErrorUtils
+import org.jetbrains.jet.lang.types.SubtypingRepresentatives
+import org.jetbrains.jet.lang.types.AbstractJetType
+import org.jetbrains.jet.lang.types.DelegatingType
+import org.jetbrains.jet.lang.types.JetTypeImpl
+import org.jetbrains.jet.lang.types.TypeUtils
 
 public class CapturedTypeConstructor(
         public val typeProjection: TypeProjection
@@ -56,10 +61,30 @@ public class CapturedTypeConstructor(
     override fun toString() = "Captured($typeProjection)"
 }
 
-public fun createCapturedType(typeProjection: TypeProjection): JetType {
-    val scope = ErrorUtils.createErrorScope("No member resolution should be done on captured type, " +
-                                            "it used only during constraint system resolution", true)
-    return JetTypeImpl(Annotations.EMPTY, CapturedTypeConstructor(typeProjection), false, listOf(), scope)
+public class CapturedType(
+        private val typeProjection: TypeProjection
+): DelegatingType(), SubtypingRepresentatives {
+
+    private val delegateType = run {
+        val scope = ErrorUtils.createErrorScope(
+                "No member resolution should be done on captured type, it used only during constraint system resolution", true)
+        JetTypeImpl(Annotations.EMPTY, CapturedTypeConstructor(typeProjection), false, listOf(), scope)
+    }
+
+    override fun getDelegate(): JetType = delegateType
+
+    override val subTypeRepresentative: JetType
+        get() = representative(OUT_VARIANCE, KotlinBuiltIns.getInstance().getNullableAnyType())
+
+    override val superTypeRepresentative: JetType
+        get() = representative(IN_VARIANCE, KotlinBuiltIns.getInstance().getNothingType())
+
+    private fun representative(variance: Variance, default: JetType) =
+        if (typeProjection.getProjectionKind() == variance) typeProjection.getType() else default
+
+    override fun sameTypeConstructor(type: JetType) = delegateType.getConstructor() === type.getConstructor()
 }
 
+public fun createCapturedType(typeProjection: TypeProjection): JetType = CapturedType(typeProjection)
+
 public fun JetType.isCaptured(): Boolean = getConstructor() is CapturedTypeConstructor

core/descriptors/src/org/jetbrains/jet/lang/types/TypeCapabilities.kt

@@ -31,9 +31,11 @@ public trait Specificity : TypeCapability {
     public fun getSpecificityRelationTo(otherType: JetType): Relation
 }
 
-fun JetType.getSpecificityRelationTo(otherType: JetType) = this.getCapability(javaClass<Specificity>())?.getSpecificityRelationTo(otherType) ?: Specificity.Relation.DONT_KNOW
+fun JetType.getSpecificityRelationTo(otherType: JetType) =
+        this.getCapability(javaClass<Specificity>())?.getSpecificityRelationTo(otherType) ?: Specificity.Relation.DONT_KNOW
 
-fun oneMoreSpecificThanAnother(a: JetType, b: JetType) = a.getSpecificityRelationTo(b) != Specificity.Relation.DONT_KNOW || b.getSpecificityRelationTo(a) != Specificity.Relation.DONT_KNOW
+fun oneMoreSpecificThanAnother(a: JetType, b: JetType) =
+        a.getSpecificityRelationTo(b) != Specificity.Relation.DONT_KNOW || b.getSpecificityRelationTo(a) != Specificity.Relation.DONT_KNOW
 
 // To facilitate laziness, any JetType implementation may inherit from this trait,
 // even if it turns out that the type an instance represents is not actually a type variable
@@ -52,4 +54,23 @@ public fun JetType.isCustomTypeVariable(): Boolean = this.getCapability(javaClas
 public fun JetType.getCustomTypeVariable(): CustomTypeVariable? =
         this.getCapability(javaClass<CustomTypeVariable>())?.let {
             if (it.isTypeVariable) it else null
-        }
+        }
+
+public trait SubtypingRepresentatives : TypeCapability {
+    public val subTypeRepresentative: JetType
+    public val superTypeRepresentative: JetType
+
+    public fun sameTypeConstructor(type: JetType): Boolean
+}
+
+public fun JetType.getSubtypeRepresentative(): JetType =
+        this.getCapability(javaClass<SubtypingRepresentatives>())?.subTypeRepresentative ?: this
+
+public fun JetType.getSupertypeRepresentative(): JetType =
+        this.getCapability(javaClass<SubtypingRepresentatives>())?.superTypeRepresentative ?: this
+
+public fun sameTypeConstructors(first: JetType, second: JetType): Boolean {
+    val typeRangeCapability = javaClass<SubtypingRepresentatives>()
+    return first.getCapability(typeRangeCapability)?.sameTypeConstructor(second) ?: false
+           || second.getCapability(typeRangeCapability)?.sameTypeConstructor(first) ?: false
+}

core/descriptors/src/org/jetbrains/jet/lang/types/checker/TypeCheckingProcedure.java

@@ -183,12 +183,19 @@ public class TypeCheckingProcedure {
     }
 
     public boolean isSubtypeOf(@NotNull JetType subtype, @NotNull JetType supertype) {
-        if (TypesPackage.isFlexible(subtype)) {
-            return isSubtypeOf(TypesPackage.flexibility(subtype).getLowerBound(), supertype);
+        if (TypesPackage.sameTypeConstructors(subtype, supertype)) {
+            return !subtype.isMarkedNullable() || supertype.isMarkedNullable();
         }
-        if (TypesPackage.isFlexible(supertype)) {
-            return isSubtypeOf(subtype, TypesPackage.flexibility(supertype).getUpperBound());
+        JetType subtypeRepresentative = TypesPackage.getSubtypeRepresentative(subtype);
+        JetType supertypeRepresentative = TypesPackage.getSupertypeRepresentative(supertype);
+        if (subtypeRepresentative != subtype || supertypeRepresentative != supertype) {
+            // recursive invocation for possible chain of representatives
+            return isSubtypeOf(subtypeRepresentative, supertypeRepresentative);
         }
+        return isSubtypeOfForRepresentatives(subtype, supertype);
+    }
+
+    private boolean isSubtypeOfForRepresentatives(JetType subtype, JetType supertype) {
         if (subtype.isError() || supertype.isError()) {
             return true;
         }

core/descriptors/src/org/jetbrains/jet/lang/types/flexibleTypes.kt

@@ -34,7 +34,7 @@ public trait FlexibleTypeCapabilities {
     }
 }
 
-public trait Flexibility : TypeCapability {
+public trait Flexibility : TypeCapability, SubtypingRepresentatives {
     class object {
         // This is a "magic" classifier: when type resolver sees it in the code, e.g. ft<Foo, Foo?>, instead of creating a normal type,
         // it creates a flexible type, e.g. (Foo..Foo?).
@@ -48,6 +48,14 @@ public trait Flexibility : TypeCapability {
     public val upperBound: JetType
 
     public val extraCapabilities: FlexibleTypeCapabilities
+
+    override val subTypeRepresentative: JetType
+        get() = lowerBound
+
+    override val superTypeRepresentative: JetType
+        get() = upperBound
+
+    override fun sameTypeConstructor(type: JetType) = false
 }
 
 public fun JetType.isFlexible(): Boolean = this.getCapability(javaClass<Flexibility>()) != null