Move DeclarationDescriptor.substitute to separate interface Substitutable

To get rid of pointless/confusing implementations in ModuleDescriptor,
PackageViewDescriptor, TypeParameterDescriptor and others.

Note that there are still implementations that do not make sense, for
example in those subclasses of VariableDescriptor which are not also
subclasses of CallableMemberDescriptor (e.g. ValueParameterDescriptor).
Those can be removed by making CallableMemberDescriptor (instead of
CallableDescriptor) inherit from Substitutable. However, that would
require more changes in the compiler because CallableDescriptor is used
rather often in places where in fact only CallableMemberDescriptor
instances can appear.

Explicit return types and casts are required in some places now because
there's no single non-trivial supertype for
ClassifierDescriptorWithTypeParameters and CallableDescriptor.
Previously it was DeclarationDescriptorWithVisibility, now it's both
that and Substitutable<...>

compiler/backend/src/org/jetbrains/kotlin/codegen/context/RootContext.java

@@ -23,7 +23,6 @@ import org.jetbrains.kotlin.descriptors.DeclarationDescriptor;
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptorVisitor;
 import org.jetbrains.kotlin.descriptors.annotations.Annotations;
 import org.jetbrains.kotlin.name.Name;
-import org.jetbrains.kotlin.types.TypeSubstitutor;
 
 public class RootContext extends CodegenContext<RootContext.FakeDescriptor> {
     private final GenerationState state;
@@ -56,11 +55,6 @@ public class RootContext extends CodegenContext<RootContext.FakeDescriptor> {
             throw new IllegalStateException();
         }
 
-        @Override
-        public DeclarationDescriptor substitute(@NotNull TypeSubstitutor substitutor) {
-            throw new IllegalStateException();
-        }
-
         @Override
         public <R, D> R accept(DeclarationDescriptorVisitor<R, D> visitor, D data) {
             throw new IllegalStateException();

compiler/frontend/src/org/jetbrains/kotlin/resolve/OverloadResolver.kt

@@ -91,7 +91,7 @@ class OverloadResolver(
 
         collectModulePackageMembersWithSameName(
                 packageMembersByName,
-                c.functions.values + c.declaredClasses.values + c.typeAliases.values,
+                (c.functions.values as Collection<DeclarationDescriptor>) + c.declaredClasses.values + c.typeAliases.values,
                 overloadFilter
         ) {
             scope, name ->

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/checkers/UnderscoreUsageChecker.kt

@@ -31,7 +31,7 @@ object UnderscoreUsageChecker : CallChecker {
     override fun check(resolvedCall: ResolvedCall<*>, reportOn: PsiElement, context: CallCheckerContext) {
         if (resolvedCall is VariableAsFunctionResolvedCall) return
         val descriptor = resolvedCall.resultingDescriptor
-        val namedDescriptor = if (descriptor is ConstructorDescriptor) descriptor.containingDeclaration else descriptor
+        val namedDescriptor: DeclarationDescriptor = (descriptor as? ConstructorDescriptor)?.containingDeclaration ?: descriptor
         if (!namedDescriptor.name.asString().isUnderscoreOnlyName()) return
         checkCallElement(resolvedCall.call.callElement, context)
     }

compiler/frontend/src/org/jetbrains/kotlin/resolve/lazy/FileScopeFactory.kt

@@ -38,7 +38,6 @@ import org.jetbrains.kotlin.resolve.source.KotlinSourceElement
 import org.jetbrains.kotlin.script.getScriptExternalDependencies
 import org.jetbrains.kotlin.storage.StorageManager
 import org.jetbrains.kotlin.storage.getValue
-import org.jetbrains.kotlin.types.TypeSubstitutor
 import org.jetbrains.kotlin.utils.Printer
 
 data class FileScopes(val lexicalScope: LexicalScope, val importingScope: ImportingScope, val importResolver: ImportResolver)
@@ -236,7 +235,6 @@ class FileScopeFactory(
 
         override fun getOriginal() = this
         override val annotations: Annotations get() = Annotations.EMPTY
-        override fun substitute(substitutor: TypeSubstitutor) = this
 
         override fun <R : Any?, D : Any?> accept(visitor: DeclarationDescriptorVisitor<R, D>?, data: D): R {
             throw UnsupportedOperationException()

compiler/frontend/src/org/jetbrains/kotlin/resolve/lazy/descriptors/LazyAnnotations.kt

@@ -30,7 +30,6 @@ import org.jetbrains.kotlin.resolve.lazy.LazyEntity
 import org.jetbrains.kotlin.resolve.scopes.LexicalScope
 import org.jetbrains.kotlin.resolve.source.toSourceElement
 import org.jetbrains.kotlin.storage.StorageManager
-import org.jetbrains.kotlin.types.TypeSubstitutor
 
 abstract class LazyAnnotationsContext(
         val annotationResolver: AnnotationResolver,
@@ -172,7 +171,6 @@ class LazyAnnotationDescriptor(
         override fun getName() = Name.special("< file descriptor for annotation resolution >")
 
         private fun error(): Nothing = error("This method should not be called")
-        override fun substitute(substitutor: TypeSubstitutor): DeclarationDescriptor? = error()
         override fun <R : Any?, D : Any?> accept(visitor: DeclarationDescriptorVisitor<R, D>?, data: D): R = error()
         override fun acceptVoid(visitor: DeclarationDescriptorVisitor<Void, Void>?) = error()
 

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/descriptors/IrBuiltinsPackageFragmentDescriptor.kt

@@ -21,7 +21,6 @@ import org.jetbrains.kotlin.descriptors.annotations.Annotations
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.resolve.scopes.MemberScope
-import org.jetbrains.kotlin.types.TypeSubstitutor
 
 interface IrBuiltinsPackageFragmentDescriptor : PackageFragmentDescriptor
 
@@ -40,7 +39,6 @@ class IrBuiltinsPackageFragmentDescriptorImpl(
     override fun getOriginal(): DeclarationDescriptorWithSource = this
     override fun getSource(): SourceElement = SourceElement.NO_SOURCE
     override val annotations: Annotations = Annotations.EMPTY
-    override fun substitute(substitutor: TypeSubstitutor): DeclarationDescriptor = throw UnsupportedOperationException()
 
     override fun <R : Any?, D : Any?> accept(visitor: DeclarationDescriptorVisitor<R, D>, data: D): R {
         return visitor.visitPackageFragmentDescriptor(this, data)
@@ -50,5 +48,3 @@ class IrBuiltinsPackageFragmentDescriptorImpl(
         visitor.visitPackageFragmentDescriptor(this, null)
     }
 }
-
-

compiler/tests-common/org/jetbrains/kotlin/jvm/runtime/AbstractJvmRuntimeDescriptorLoaderTest.kt

@@ -45,7 +45,6 @@ import org.jetbrains.kotlin.test.KotlinTestUtils.TestFileFactoryNoModules
 import org.jetbrains.kotlin.test.util.DescriptorValidator.ValidationVisitor.errorTypesForbidden
 import org.jetbrains.kotlin.test.util.RecursiveDescriptorComparator
 import org.jetbrains.kotlin.test.util.RecursiveDescriptorComparator.Configuration
-import org.jetbrains.kotlin.types.TypeSubstitutor
 import org.jetbrains.kotlin.utils.Printer
 import org.jetbrains.kotlin.utils.sure
 import java.io.File
@@ -221,7 +220,6 @@ abstract class AbstractJvmRuntimeDescriptorLoaderTest : TestCaseWithTmpdir() {
 
         override fun getContainingDeclaration() = null
         override fun getOriginal() = throw UnsupportedOperationException()
-        override fun substitute(substitutor: TypeSubstitutor) = throw UnsupportedOperationException()
         override fun acceptVoid(visitor: DeclarationDescriptorVisitor<Void, Void>?) = throw UnsupportedOperationException()
         override fun getName() = throw UnsupportedOperationException()
         override val annotations: Annotations