JVM_IR: deal with facade classes when computing signature

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/IrUtils.kt

@@ -606,4 +606,10 @@ internal fun <T> IrConst<T>.shallowCopy() = IrConstImpl(
     type,
     kind,
     value
-)
+)
+
+val IrDeclarationParent.isFacadeClass: Boolean
+    get() = this is IrClass &&
+            (origin == IrDeclarationOrigin.JVM_MULTIFILE_CLASS ||
+                    origin == IrDeclarationOrigin.FILE_CLASS ||
+                    origin == IrDeclarationOrigin.SYNTHETIC_FILE_CLASS)

compiler/ir/serialization.common/src/org/jetbrains/kotlin/backend/common/serialization/mangle/ir/IrMangleComputer.kt

@@ -14,6 +14,7 @@ import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
 import org.jetbrains.kotlin.ir.symbols.IrTypeParameterSymbol
 import org.jetbrains.kotlin.ir.types.*
+import org.jetbrains.kotlin.ir.util.isFacadeClass
 import org.jetbrains.kotlin.ir.util.isVararg
 import org.jetbrains.kotlin.ir.util.parentAsClass
 import org.jetbrains.kotlin.ir.util.render
@@ -293,7 +294,8 @@ abstract class IrMangleComputer(protected val builder: StringBuilder, private va
         isRealExpect = isRealExpect or declaration.isExpect
 
         val container = declaration.correspondingPropertySymbol?.owner ?: declaration
-        val isStatic = declaration.dispatchReceiverParameter == null && container.parent !is IrPackageFragment
+        val isStatic = declaration.dispatchReceiverParameter == null &&
+                (container.parent !is IrPackageFragment && !container.parent.isFacadeClass)
 
         declaration.mangleFunction(false, isStatic, container)
     }

compiler/ir/serialization.common/src/org/jetbrains/kotlin/backend/common/serialization/signature/IdSignatureSerializer.kt

@@ -16,6 +16,7 @@ import org.jetbrains.kotlin.ir.overrides.isOverridableProperty
 import org.jetbrains.kotlin.ir.symbols.IrFileSymbol
 import org.jetbrains.kotlin.ir.util.IdSignature
 import org.jetbrains.kotlin.ir.util.KotlinMangler
+import org.jetbrains.kotlin.ir.util.isFacadeClass
 import org.jetbrains.kotlin.ir.util.render
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
 import org.jetbrains.kotlin.ir.visitors.acceptVoid
@@ -79,7 +80,9 @@ class PublicIdSignatureComputer(val mangler: KotlinMangler.IrMangler) : IdSignat
 
         private fun collectParents(declaration: IrDeclarationWithName) {
             declaration.parent.acceptVoid(this)
-            classFqnSegments.add(declaration.name.asString())
+            if (declaration !is IrClass || !declaration.isFacadeClass) {
+                classFqnSegments.add(declaration.name.asString())
+            }
         }
 
         private fun setDescription(declaration: IrDeclaration) {
@@ -190,10 +193,6 @@ class PublicIdSignatureComputer(val mangler: KotlinMangler.IrMangler) : IdSignat
                 hashId = declaration.hashId()
             }
         }
-
-        override fun visitField(declaration: IrField) {
-            collectFqNames(declaration)
-        }
     }
 }