[FIR] Fix removeAtInt test

compiler/testData/diagnostics/tests/j+k/collectionOverrides/removeAtInt.fir.kt

@@ -0,0 +1,32 @@
+// JAVAC_EXPECTED_FILE
+// FILE: A.java
+abstract public class A extends B {
+    public Integer removeAt(int x) { }
+    public boolean remove(Integer x) { }
+}
+
+// FILE: main.kt
+import java.util.*;
+
+abstract class B : MutableList<Int>, AbstractList<Int>() {
+    override fun removeAt(index: Int): Int = null!!
+    override fun remove(element: Int): <!RETURN_TYPE_MISMATCH_ON_OVERRIDE!>Boolean<!> = null!!
+}
+
+abstract class D : AbstractList<Int>() {
+    // removeAt() doesn't exist in java/util/AbstractList, it's a
+    // fake override of the method from kotlin/collections/MutableList
+    override fun removeAt(index: Int): Int = null!!
+    // AbstractList::remove() should return Int here. No fake overrides created.
+    // This may be a bug because the old compiler doesn't report a diagnostic here.
+    override fun remove(element: Int): <!RETURN_TYPE_MISMATCH_ON_OVERRIDE!>Boolean<!> = null!!
+}
+
+fun main(a: A, b: B, c: ArrayList<Int>) {
+    a.remove(1)
+    a.removeAt(0)
+    b.remove(1)
+    b.removeAt(0)
+    c.remove(1)
+    c.removeAt(0)
+}

compiler/testData/diagnostics/tests/j+k/collectionOverrides/removeAtInt.kt

@@ -1,4 +1,3 @@
-// FIR_IDENTICAL
 // JAVAC_EXPECTED_FILE
 // FILE: A.java
 abstract public class A extends B {
@@ -11,7 +10,7 @@ import java.util.*;
 
 abstract class B : MutableList<Int>, AbstractList<Int>() {
     override fun removeAt(index: Int): Int = null!!
-    override fun remove(element: Int): <!RETURN_TYPE_MISMATCH_ON_OVERRIDE!>Boolean<!> = null!!
+    override fun remove(element: Int): Boolean = null!!
 }
 
 abstract class D : AbstractList<Int>() {
@@ -20,7 +19,7 @@ abstract class D : AbstractList<Int>() {
     override fun removeAt(index: Int): Int = null!!
     // AbstractList::remove() should return Int here. No fake overrides created.
     // This may be a bug because the old compiler doesn't report a diagnostic here.
-    override fun remove(element: Int): <!RETURN_TYPE_MISMATCH_ON_OVERRIDE!>Boolean<!> = null!!
+    override fun remove(element: Int): Boolean = null!!
 }
 
 fun main(a: A, b: B, c: ArrayList<Int>) {

compiler/testData/diagnostics/tests/j+k/collectionOverrides/removeAtInt.txt

@@ -74,3 +74,37 @@ public abstract class B : kotlin.collections.MutableList<kotlin.Int>, java.util.
     public open override /*1*/ /*fake_override*/ fun </*0*/ T : kotlin.Any!> toArray(/*0*/ a: kotlin.Array<(out) T!>!): kotlin.Array<(out) T!>!
     public open override /*2*/ /*fake_override*/ fun toString(): kotlin.String
 }
+
+public abstract class D : java.util.AbstractList<kotlin.Int> {
+    public constructor D()
+    protected/*protected and package*/ final override /*1*/ /*fake_override*/ var modCount: kotlin.Int
+    public abstract override /*1*/ /*fake_override*/ val size: kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun add(/*0*/ index: kotlin.Int, /*1*/ element: kotlin.Int!): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun add(/*0*/ element: kotlin.Int!): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun addAll(/*0*/ index: kotlin.Int, /*1*/ elements: kotlin.collections.Collection<kotlin.Int!>): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun addAll(/*0*/ elements: kotlin.collections.Collection<kotlin.Int!>): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun clear(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun contains(/*0*/ element: kotlin.Int!): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun containsAll(/*0*/ elements: kotlin.collections.Collection<kotlin.Int!>): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract override /*1*/ /*fake_override*/ fun get(/*0*/ index: kotlin.Int): kotlin.Int!
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun indexOf(/*0*/ element: kotlin.Int!): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun isEmpty(): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun iterator(): kotlin.collections.MutableIterator<kotlin.Int!>
+    public open override /*1*/ /*fake_override*/ fun lastIndexOf(/*0*/ element: kotlin.Int!): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun listIterator(): kotlin.collections.MutableListIterator<kotlin.Int!>
+    public open override /*1*/ /*fake_override*/ fun listIterator(/*0*/ index: kotlin.Int): kotlin.collections.MutableListIterator<kotlin.Int!>
+    invisible_fake open override /*1*/ /*fake_override*/ fun outOfBoundsMsg(/*0*/ index: kotlin.Int): kotlin.String!
+    invisible_fake open override /*1*/ /*fake_override*/ fun rangeCheckForAdd(/*0*/ index: kotlin.Int): kotlin.Unit
+    public open override /*1*/ fun remove(/*0*/ element: kotlin.Int): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun removeAll(/*0*/ elements: kotlin.collections.Collection<kotlin.Int!>): kotlin.Boolean
+    public open override /*1*/ fun removeAt(/*0*/ index: kotlin.Int): kotlin.Int
+    protected/*protected and package*/ open override /*1*/ /*fake_override*/ fun removeRange(/*0*/ fromIndex: kotlin.Int, /*1*/ toIndex: kotlin.Int): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun retainAll(/*0*/ elements: kotlin.collections.Collection<kotlin.Int!>): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun set(/*0*/ index: kotlin.Int, /*1*/ element: kotlin.Int!): kotlin.Int!
+    public open override /*1*/ /*fake_override*/ fun subList(/*0*/ fromIndex: kotlin.Int, /*1*/ toIndex: kotlin.Int): kotlin.collections.MutableList<kotlin.Int!>
+    public open override /*1*/ /*fake_override*/ fun toArray(): kotlin.Array<(out) kotlin.Any!>!
+    public open override /*1*/ /*fake_override*/ fun </*0*/ T : kotlin.Any!> toArray(/*0*/ a: kotlin.Array<(out) T!>!): kotlin.Array<(out) T!>!
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}