FIC: Move sam related methods to ClassDescriptor, fix JVM backend part

core/descriptors.jvm/src/org/jetbrains/kotlin/load/java/descriptors/JavaClassDescriptor.java

@@ -16,18 +16,7 @@
 
 package org.jetbrains.kotlin.load.java.descriptors;
 
-import org.jetbrains.annotations.Nullable;
 import org.jetbrains.kotlin.descriptors.ClassDescriptor;
-import org.jetbrains.kotlin.types.SimpleType;
 
 public interface JavaClassDescriptor extends ClassDescriptor {
-    // Use SingleAbstractMethodUtils.getFunctionTypeForSamInterface() where possible. This is only a fallback
-    @Nullable
-    SimpleType getDefaultFunctionTypeForSamInterface();
-
-    /**
-     * May return false even in case when the class is not SAM interface, but returns true only if it's definitely not a SAM.
-     * But it should work much faster than the exact check.
-     */
-    boolean isDefinitelyNotSamInterface();
 }

core/descriptors/src/org/jetbrains/kotlin/descriptors/ClassDescriptor.java

@@ -98,4 +98,14 @@ public interface ClassDescriptor extends ClassifierDescriptorWithTypeParameters,
     @NotNull
     @Override
     ClassDescriptor getOriginal();
+
+    // Use SingleAbstractMethodUtils.getFunctionTypeForSamInterface() where possible. This is only a fallback
+    @Nullable
+    SimpleType getDefaultFunctionTypeForSamInterface();
+
+    /**
+     * May return false even in case when the class is not SAM interface, but returns true only if it's definitely not a SAM.
+     * But it should work much faster than the exact check.
+     */
+    boolean isDefinitelyNotSamInterface();
 }

core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/AbstractClassDescriptor.java

@@ -19,6 +19,7 @@ package org.jetbrains.kotlin.descriptors.impl;
 import kotlin.jvm.functions.Function0;
 import kotlin.jvm.functions.Function1;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 import org.jetbrains.kotlin.descriptors.*;
 import org.jetbrains.kotlin.name.Name;
 import org.jetbrains.kotlin.resolve.DescriptorUtils;
@@ -176,4 +177,15 @@ public abstract class AbstractClassDescriptor extends ModuleAwareClassDescriptor
     public <R, D> R accept(DeclarationDescriptorVisitor<R, D> visitor, D data) {
         return visitor.visitClassDescriptor(this, data);
     }
+
+    @Nullable
+    @Override
+    public SimpleType getDefaultFunctionTypeForSamInterface() {
+        return null;
+    }
+
+    @Override
+    public boolean isDefinitelyNotSamInterface() {
+        return false;
+    }
 }

core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/LazySubstitutingClassDescriptor.java

@@ -308,4 +308,25 @@ public class LazySubstitutingClassDescriptor extends ModuleAwareClassDescriptor
     public Collection<ClassDescriptor> getSealedSubclasses() {
         return original.getSealedSubclasses();
     }
+
+    @Nullable
+    @Override
+    public SimpleType getDefaultFunctionTypeForSamInterface() {
+        SimpleType type = original.getDefaultFunctionTypeForSamInterface();
+        if (type == null || originalSubstitutor.isEmpty()) return type;
+
+        TypeSubstitutor substitutor = getSubstitutor();
+        KotlinType substitutedType = substitutor.substitute(type, Variance.INVARIANT);
+
+        assert substitutedType instanceof SimpleType :
+                "Substitution for SimpleType should also be a SimpleType, but it is " + substitutedType + "\n" +
+                "Unsubstituted: " + type;
+
+        return (SimpleType) substitutedType;
+    }
+
+    @Override
+    public boolean isDefinitelyNotSamInterface() {
+        return original.isDefinitelyNotSamInterface();
+    }
 }