FIC: Add synthetic constructors for fun interfaces aka explicit FIC

compiler/frontend.java/src/org/jetbrains/kotlin/load/java/sam/SamConstructorDescriptor.kt

@@ -17,18 +17,18 @@
 package org.jetbrains.kotlin.load.java.sam
 
 import org.jetbrains.kotlin.descriptors.CallableMemberDescriptor
+import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
 import org.jetbrains.kotlin.descriptors.SimpleFunctionDescriptor
 import org.jetbrains.kotlin.descriptors.impl.SimpleFunctionDescriptorImpl
 import org.jetbrains.kotlin.descriptors.synthetic.SyntheticMemberDescriptor
-import org.jetbrains.kotlin.load.java.descriptors.JavaClassDescriptor
 import org.jetbrains.kotlin.resolve.scopes.DescriptorKindExclude
 
-interface SamConstructorDescriptor : SimpleFunctionDescriptor, SyntheticMemberDescriptor<JavaClassDescriptor>
+interface SamConstructorDescriptor : SimpleFunctionDescriptor, SyntheticMemberDescriptor<ClassDescriptor>
 
 class SamConstructorDescriptorImpl(
         containingDeclaration: DeclarationDescriptor,
-        private val samInterface: JavaClassDescriptor
+        private val samInterface: ClassDescriptor
 ) : SimpleFunctionDescriptorImpl(
         containingDeclaration,
         null,
@@ -37,7 +37,7 @@ class SamConstructorDescriptorImpl(
         CallableMemberDescriptor.Kind.SYNTHESIZED,
         samInterface.source
 ), SamConstructorDescriptor {
-    override val baseDescriptorForSynthetic: JavaClassDescriptor
+    override val baseDescriptorForSynthetic: ClassDescriptor
         get() = samInterface
 }
 

compiler/frontend.java/src/org/jetbrains/kotlin/load/java/sam/SamTypeAliasConstructorDescriptor.kt

@@ -16,12 +16,8 @@
 
 package org.jetbrains.kotlin.load.java.sam
 
-import org.jetbrains.kotlin.descriptors.CallableMemberDescriptor
-import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
-import org.jetbrains.kotlin.descriptors.DeclarationDescriptorWithNavigationSubstitute
-import org.jetbrains.kotlin.descriptors.TypeAliasDescriptor
+import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.descriptors.impl.SimpleFunctionDescriptorImpl
-import org.jetbrains.kotlin.load.java.descriptors.JavaClassDescriptor
 
 interface SamTypeAliasConstructorDescriptor : SamConstructorDescriptor, DeclarationDescriptorWithNavigationSubstitute {
     val typeAliasDescriptor: TypeAliasDescriptor
@@ -41,6 +37,6 @@ class SamTypeAliasConstructorDescriptorImpl(
         CallableMemberDescriptor.Kind.SYNTHESIZED,
         typeAliasDescriptor.source
 ), SamTypeAliasConstructorDescriptor {
-    override val baseDescriptorForSynthetic: JavaClassDescriptor
+    override val baseDescriptorForSynthetic: ClassDescriptor
         get() = samInterfaceConstructorDescriptor.baseDescriptorForSynthetic
 }

compiler/frontend.java/src/org/jetbrains/kotlin/load/java/sam/SingleAbstractMethodUtils.java

@@ -28,6 +28,7 @@ import org.jetbrains.kotlin.resolve.SamConversionResolver;
 import org.jetbrains.kotlin.load.java.descriptors.JavaClassConstructorDescriptor;
 import org.jetbrains.kotlin.load.java.descriptors.JavaClassDescriptor;
 import org.jetbrains.kotlin.load.java.descriptors.JavaMethodDescriptor;
+import org.jetbrains.kotlin.load.java.lazy.descriptors.LazyJavaClassDescriptor;
 import org.jetbrains.kotlin.name.Name;
 import org.jetbrains.kotlin.name.SpecialNames;
 import org.jetbrains.kotlin.resolve.DescriptorUtils;
@@ -167,7 +168,7 @@ public class SingleAbstractMethodUtils {
     @NotNull
     public static SamConstructorDescriptor createSamConstructorFunction(
             @NotNull DeclarationDescriptor owner,
-            @NotNull JavaClassDescriptor samInterface,
+            @NotNull ClassDescriptor samInterface,
             @NotNull SamConversionResolver samResolver
     ) {
         assert getSingleAbstractMethodOrNull(samInterface) != null : samInterface;
@@ -182,7 +183,7 @@ public class SingleAbstractMethodUtils {
     }
 
     private static void initializeSamConstructorDescriptor(
-            @NotNull JavaClassDescriptor samInterface,
+            @NotNull ClassDescriptor samInterface,
             @NotNull SimpleFunctionDescriptorImpl samConstructor,
             @NotNull List<TypeParameterDescriptor> samTypeParameters,
             @NotNull KotlinType unsubstitutedSamType,
@@ -224,7 +225,7 @@ public class SingleAbstractMethodUtils {
     ) {
         SamTypeAliasConstructorDescriptorImpl result = new SamTypeAliasConstructorDescriptorImpl(typeAliasDescriptor, underlyingSamConstructor);
 
-        JavaClassDescriptor samInterface = underlyingSamConstructor.getBaseDescriptorForSynthetic();
+        ClassDescriptor samInterface = underlyingSamConstructor.getBaseDescriptorForSynthetic();
         List<TypeParameterDescriptor> samTypeParameters = typeAliasDescriptor.getTypeConstructor().getParameters();
         SimpleType unsubstitutedSamType = typeAliasDescriptor.getExpandedType();
         initializeSamConstructorDescriptor(samInterface, result, samTypeParameters, unsubstitutedSamType, samResolver);
@@ -232,6 +233,15 @@ public class SingleAbstractMethodUtils {
         return result;
     }
 
+    public static boolean isSamClassDescriptor(@NotNull ClassDescriptor descriptor) {
+        if (descriptor.isFun()) return true;
+        if (descriptor instanceof LazyJavaClassDescriptor &&
+            ((LazyJavaClassDescriptor) descriptor).getDefaultFunctionTypeForSamInterface() != null
+        ) return true;
+
+        return false;
+    }
+
     public static boolean isSamType(@NotNull KotlinType type) {
         ClassifierDescriptor descriptor = type.getConstructor().getDeclarationDescriptor();
         if (descriptor instanceof ClassDescriptor && ((ClassDescriptor) descriptor).isFun()) return true;

compiler/frontend.java/src/org/jetbrains/kotlin/synthetic/SamAdapterFunctionsScope.kt

@@ -30,7 +30,6 @@ import org.jetbrains.kotlin.resolve.SamConversionResolver
 import org.jetbrains.kotlin.load.java.descriptors.JavaClassConstructorDescriptor
 import org.jetbrains.kotlin.load.java.descriptors.JavaClassDescriptor
 import org.jetbrains.kotlin.load.java.descriptors.JavaMethodDescriptor
-import org.jetbrains.kotlin.load.java.lazy.descriptors.LazyJavaClassDescriptor
 import org.jetbrains.kotlin.load.java.sam.SamAdapterDescriptor
 import org.jetbrains.kotlin.load.java.sam.SamConstructorDescriptor
 import org.jetbrains.kotlin.load.java.sam.SingleAbstractMethodUtils
@@ -73,7 +72,7 @@ class SamAdapterFunctionsScope(
             }
 
     private val samConstructorForClassifier =
-            storageManager.createMemoizedFunction<JavaClassDescriptor, SamConstructorDescriptor> { classifier ->
+            storageManager.createMemoizedFunction<ClassDescriptor, SamConstructorDescriptor> { classifier ->
                 SingleAbstractMethodUtils.createSamConstructorFunction(classifier.containingDeclaration, classifier, samResolver)
             }
 
@@ -259,13 +258,15 @@ class SamAdapterFunctionsScope(
             return getTypeAliasSamConstructor(classifier)
         }
 
-        if (classifier !is LazyJavaClassDescriptor || classifier.defaultFunctionTypeForSamInterface == null) return null
+        if (classifier !is ClassDescriptor) return null
+        if (!SingleAbstractMethodUtils.isSamClassDescriptor(classifier)) return null
+
         return samConstructorForClassifier(classifier)
     }
 
     private fun getTypeAliasSamConstructor(classifier: TypeAliasDescriptor): SamConstructorDescriptor? {
         val classDescriptor = classifier.classDescriptor ?: return null
-        if (classDescriptor !is LazyJavaClassDescriptor || classDescriptor.defaultFunctionTypeForSamInterface == null) return null
+        if (!SingleAbstractMethodUtils.isSamClassDescriptor(classDescriptor)) return null
 
         return SingleAbstractMethodUtils.createTypeAliasSamConstructorFunction(
                 classifier, samConstructorForClassifier(classDescriptor), samResolver)