Don't generate primary constructor body for expect classes

compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/BodyGenerator.kt

@@ -232,7 +232,9 @@ class BodyGenerator(
                 // If we are here, we didn't find a superclass entry in super types.
                 // Thus, super class should be Any.
                 val superClass = classDescriptor.getSuperClassOrAny()
-                assert(KotlinBuiltIns.isAny(superClass)) { "$classDescriptor: Super class should be any: $superClass" }
+                assert(KotlinBuiltIns.isAny(superClass)) {
+                    "$classDescriptor: Super class should be any: $superClass"
+                }
                 generateAnySuperConstructorCall(irBlockBody, ktClassOrObject)
             }
         }

compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/FunctionGenerator.kt

@@ -196,7 +196,10 @@ class FunctionGenerator(declarationGenerator: DeclarationGenerator) : Declaratio
         ktClassOrObject: KtClassOrObject
     ): IrConstructor =
         declareConstructor(ktClassOrObject, ktClassOrObject.primaryConstructor ?: ktClassOrObject, primaryConstructorDescriptor) {
-            generatePrimaryConstructorBody(ktClassOrObject)
+            if (primaryConstructorDescriptor.isExpect)
+                null
+            else
+                generatePrimaryConstructorBody(ktClassOrObject)
         }
 
     fun generateSecondaryConstructor(ktConstructor: KtSecondaryConstructor): IrConstructor =
@@ -215,7 +218,7 @@ class FunctionGenerator(declarationGenerator: DeclarationGenerator) : Declaratio
         ktConstructorElement: KtElement,
         ktParametersElement: KtElement,
         constructorDescriptor: ClassConstructorDescriptor,
-        generateBody: BodyGenerator.() -> IrBody
+        generateBody: BodyGenerator.() -> IrBody?
     ): IrConstructor =
         context.symbolTable.declareConstructor(
             ktConstructorElement.startOffset, ktConstructorElement.endOffset, IrDeclarationOrigin.DEFINED, constructorDescriptor

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrConstructorImpl.kt

@@ -62,7 +62,7 @@ class IrConstructorImpl(
         endOffset: Int,
         origin: IrDeclarationOrigin,
         descriptor: ClassConstructorDescriptor,
-        body: IrBody
+        body: IrBody?
     ) : this(startOffset, endOffset, origin, descriptor) {
         this.body = body
     }

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

@@ -121,7 +121,7 @@ open class DeepCopyIrTree : IrElementTransformerVoid() {
             declaration.startOffset, declaration.endOffset,
             mapDeclarationOrigin(declaration.origin),
             mapConstructorDeclaration(declaration.descriptor),
-            declaration.body!!.transform()
+            declaration.body?.transform()
         ).transformParameters(declaration)
 
     protected fun <T : IrTypeParametersContainer> T.transformTypeParameters(