Java 8 rules for method overrides:

- base class method wins against a (default) interface method,
so an abstract base class method should always be implemented
in a derived class;

- interface methods clash regardless of abstract/default
with possibly undefined behavior at run-time,
so a class or interface should always define its own method
for methods inherited from multiple interfaces and not from base class;

- meaningful diagnostics for class inheriting conflicting JVM signatures.
Since no override will happen under Java 8 rules,
ACCIDENTAL_OVERRIDE is misleading for this case;

- update testData.

idea/testData/quickfix/changeSignature/notEditable.kt

@@ -1,11 +1,11 @@
 // "class org.jetbrains.kotlin.idea.quickfix.RemoveFunctionParametersFix" "false"
 //ERROR: No value passed for parameter other
 
-interface StringComparable {
+abstract class StringComparable {
     public fun compareTo(other: String): Int = 0
 }
 
-class X: Comparable<String>, StringComparable
+class X: Comparable<String>, StringComparable()
 
 fun main(args: Array<String>) {
     X().compareTo(<caret>)