Support equalityAxioms in isSubtypeOf()

core/descriptors/src/org/jetbrains/jet/lang/resolve/calls/inference/ConstraintSystemImpl.java

@@ -321,7 +321,7 @@ public class ConstraintSystemImpl implements ConstraintSystem {
             public boolean assertEqualTypeConstructors(
                     @NotNull TypeConstructor a, @NotNull TypeConstructor b
             ) {
-                throw new IllegalStateException("'assertEqualTypeConstructors' shouldn't be invoked inside 'isSubtypeOf'");
+                return a.equals(b);
             }
 
             @Override

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

@@ -57,27 +57,4 @@ public class JetTypeChecker {
     }
 
     private static final TypeCheckingProcedure TYPE_CHECKER = new TypeCheckingProcedure(new TypeCheckerTypingConstraints());
-
-    private static class TypeCheckerTypingConstraints implements TypingConstraints {
-        @Override
-        public boolean assertEqualTypes(@NotNull JetType a, @NotNull JetType b, @NotNull TypeCheckingProcedure typeCheckingProcedure) {
-            return typeCheckingProcedure.equalTypes(a, b);
-//            return TypeUtils.equalTypes(a, b);
-        }
-
-        @Override
-        public boolean assertEqualTypeConstructors(@NotNull TypeConstructor a, @NotNull TypeConstructor b) {
-            return a.equals(b);
-        }
-
-        @Override
-        public boolean assertSubtype(@NotNull JetType subtype, @NotNull JetType supertype, @NotNull TypeCheckingProcedure typeCheckingProcedure) {
-            return typeCheckingProcedure.isSubtypeOf(subtype, supertype);
-        }
-
-        @Override
-        public boolean noCorrespondingSupertype(@NotNull JetType subtype, @NotNull JetType supertype) {
-            return false; // type checking fails
-        }
-    }
 }

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

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2010-2014 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.jet.lang.types.checker;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.jet.lang.types.JetType;
+import org.jetbrains.jet.lang.types.TypeConstructor;
+
+class TypeCheckerTypingConstraints implements TypingConstraints {
+    @Override
+    public boolean assertEqualTypes(@NotNull JetType a, @NotNull JetType b, @NotNull TypeCheckingProcedure typeCheckingProcedure) {
+        return typeCheckingProcedure.equalTypes(a, b);
+    }
+
+    @Override
+    public boolean assertEqualTypeConstructors(@NotNull TypeConstructor a, @NotNull TypeConstructor b) {
+        return a.equals(b);
+    }
+
+    @Override
+    public boolean assertSubtype(@NotNull JetType subtype, @NotNull JetType supertype, @NotNull TypeCheckingProcedure typeCheckingProcedure) {
+        return typeCheckingProcedure.isSubtypeOf(subtype, supertype);
+    }
+
+    @Override
+    public boolean noCorrespondingSupertype(@NotNull JetType subtype, @NotNull JetType supertype) {
+        return false; // type checking fails
+    }
+}

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

@@ -32,12 +32,19 @@ public class TypeCheckingProcedure {
     // as the second parameter, applying the substitution of type arguments to it
     @Nullable
     public static JetType findCorrespondingSupertype(@NotNull JetType subtype, @NotNull JetType supertype) {
+        return findCorrespondingSupertype(subtype, supertype, new TypeCheckerTypingConstraints());
+    }
+
+    // This method returns the supertype of the first parameter that has the same constructor
+    // as the second parameter, applying the substitution of type arguments to it
+    @Nullable
+    public static JetType findCorrespondingSupertype(@NotNull JetType subtype, @NotNull JetType supertype, @NotNull TypingConstraints typingConstraints) {
         TypeConstructor constructor = subtype.getConstructor();
-        if (constructor.equals(supertype.getConstructor())) {
+        if (typingConstraints.assertEqualTypeConstructors(constructor, supertype.getConstructor())) {
             return subtype;
         }
         for (JetType immediateSupertype : constructor.getSupertypes()) {
-            JetType correspondingSupertype = findCorrespondingSupertype(immediateSupertype, supertype);
+            JetType correspondingSupertype = findCorrespondingSupertype(immediateSupertype, supertype, typingConstraints);
             if (correspondingSupertype != null) {
                 return TypeSubstitutor.create(subtype).safeSubstitute(correspondingSupertype, Variance.INVARIANT);
             }
@@ -167,7 +174,7 @@ public class TypeCheckingProcedure {
         if (KotlinBuiltIns.getInstance().isNothingOrNullableNothing(subtype)) {
             return true;
         }
-        @Nullable JetType closestSupertype = findCorrespondingSupertype(subtype, supertype);
+        @Nullable JetType closestSupertype = findCorrespondingSupertype(subtype, supertype, constraints);
         if (closestSupertype == null) {
             return constraints.noCorrespondingSupertype(subtype, supertype); // if this returns true, there still isn't any supertype to continue with
         }
@@ -177,7 +184,7 @@ public class TypeCheckingProcedure {
 
     private boolean checkSubtypeForTheSameConstructor(@NotNull JetType subtype, @NotNull JetType supertype) {
         TypeConstructor constructor = subtype.getConstructor();
-        assert constructor.equals(supertype.getConstructor()) : constructor + " is not " + supertype.getConstructor();
+        assert constraints.assertEqualTypeConstructors(constructor, supertype.getConstructor()) : constructor + " is not " + supertype.getConstructor();
 
         List<TypeProjection> subArguments = subtype.getArguments();
         List<TypeProjection> superArguments = supertype.getArguments();