Introduce TypeCapabilities concept

It encapsulates special features of type like custom substitution.

core/descriptors/src/org/jetbrains/kotlin/types/AbstractJetType.java

@@ -29,7 +29,13 @@ public abstract class AbstractJetType implements JetType {
     @Nullable
     @Override
     public <T extends TypeCapability> T getCapability(@NotNull Class<T> capabilityClass) {
-        return null;
+        return getCapabilities().getCapability(capabilityClass);
+    }
+
+    @NotNull
+    @Override
+    public TypeCapabilities getCapabilities() {
+        return TypeCapabilities.NONE.INSTANCE$;
     }
 
     @Override

core/descriptors/src/org/jetbrains/kotlin/types/DelegatingType.java

@@ -73,6 +73,12 @@ public abstract class DelegatingType implements JetType {
         return getDelegate().getCapability(capabilityClass);
     }
 
+    @NotNull
+    @Override
+    public TypeCapabilities getCapabilities() {
+        return getDelegate().getCapabilities();
+    }
+
     @Override
     public int hashCode() {
         return getDelegate().hashCode();

core/descriptors/src/org/jetbrains/kotlin/types/ErrorUtils.java

@@ -539,6 +539,12 @@ public class ErrorUtils {
             return null;
         }
 
+        @NotNull
+        @Override
+        public TypeCapabilities getCapabilities() {
+            return TypeCapabilities.NONE.INSTANCE$;
+        }
+
         @Override
         public String toString() {
             return constructor.toString() + (arguments.isEmpty() ? "" : joinToString(arguments, ", ", "<", ">", -1, "...", null));

core/descriptors/src/org/jetbrains/kotlin/types/JetType.java

@@ -52,4 +52,7 @@ public interface JetType extends Annotated {
     @KotlinSignature("fun <T : TypeCapability> getCapability(capabilityClass: Class<T>): T?")
     @Nullable
     <T extends TypeCapability> T getCapability(@NotNull Class<T> capabilityClass);
+
+    @NotNull
+    TypeCapabilities getCapabilities();
 }

core/descriptors/src/org/jetbrains/kotlin/types/TypeCapabilities.kt

@@ -20,6 +20,13 @@ import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
 
 public interface TypeCapability
 
+public interface TypeCapabilities {
+    object NONE : TypeCapabilities {
+        override fun <T : TypeCapability> getCapability(capabilityClass: Class<T>): T? = null
+    }
+
+    fun <T : TypeCapability> getCapability(capabilityClass: Class<T>): T?
+}
 public interface Specificity : TypeCapability {
 
     public enum class Relation {

core/descriptors/src/org/jetbrains/kotlin/types/TypeUtils.java

@@ -99,6 +99,12 @@ public class TypeUtils {
             return null;
         }
 
+        @NotNull
+        @Override
+        public TypeCapabilities getCapabilities() {
+            return TypeCapabilities.NONE.INSTANCE$;
+        }
+
         @Override
         public String toString() {
             return name;
@@ -798,6 +804,18 @@ public class TypeUtils {
         public TypeSubstitution getSubstitution() {
             return delegate.getSubstitution();
         }
+
+        @Nullable
+        @Override
+        public <T extends TypeCapability> T getCapability(@NotNull Class<T> capabilityClass) {
+            return delegate.getCapability(capabilityClass);
+        }
+
+        @NotNull
+        @Override
+        public TypeCapabilities getCapabilities() {
+            return delegate.getCapabilities();
+        }
     }
 
     private static class NullableType extends AbstractTypeWithKnownNullability {