Smart completion: generic functions are correctly included into the list

#KT-6375 Fixed

core/descriptors/src/org/jetbrains/jet/lang/descriptors/impl/ValueParameterDescriptorImpl.java

@@ -108,6 +108,7 @@ public class ValueParameterDescriptorImpl extends VariableDescriptorImpl impleme
     @NotNull
     @Override
     public ValueParameterDescriptor substitute(@NotNull TypeSubstitutor substitutor) {
+        if (substitutor.isEmpty()) return this;
         throw new UnsupportedOperationException(); // TODO
     }
 

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

@@ -25,6 +25,7 @@ import org.jetbrains.jet.lang.types.JetType
 import org.jetbrains.jet.lang.types.Flexibility
 import org.jetbrains.jet.lang.types.TypeConstructor
 import org.jetbrains.jet.utils.toReadOnlyList
+import org.jetbrains.jet.lang.types.checker.JetTypeChecker
 
 fun JetType.getContainedTypeParameters(): Collection<TypeParameterDescriptor> {
     val declarationDescriptor = getConstructor().getDeclarationDescriptor()
@@ -59,3 +60,6 @@ public fun JetType.getContainedAndCapturedTypeParameterConstructors(): Collectio
     return typeParameters.map { it.getTypeConstructor() }.toReadOnlyList()
 }
 
+public fun JetType.isSubtypeOf(superType: JetType): Boolean = JetTypeChecker.DEFAULT.isSubtypeOf(this, superType)
+
+