Add test for KT-51499 (occurs in FE10, already fixed in FIR)

compiler/testData/diagnostics/testsWithStdLib/experimental/fileOptInSuppressesOverride.fir.kt

@@ -0,0 +1,16 @@
+@file:OptIn(Marker::class)
+
+@RequiresOptIn
+@Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION)
+annotation class Marker
+
+@Marker
+fun experimental() {}
+
+interface MyInterface {
+    fun execute()
+}
+
+class MyClass : MyInterface {
+    override fun execute() = experimental()
+}

compiler/testData/diagnostics/testsWithStdLib/experimental/fileOptInSuppressesOverride.kt

@@ -0,0 +1,16 @@
+@file:OptIn(Marker::class)
+
+@RequiresOptIn
+@Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION)
+annotation class Marker
+
+@Marker
+fun experimental() {}
+
+interface MyInterface {
+    fun execute()
+}
+
+class MyClass : MyInterface {
+    override fun execute() = <!OPT_IN_USAGE_ERROR!>experimental<!>()
+}

compiler/testData/diagnostics/testsWithStdLib/experimental/fileOptInSuppressesOverride.txt

@@ -0,0 +1,25 @@
+package
+
+@Marker public fun experimental(): kotlin.Unit
+
+@kotlin.RequiresOptIn @kotlin.annotation.Target(allowedTargets = {AnnotationTarget.CLASS, AnnotationTarget.FUNCTION}) public final annotation class Marker : kotlin.Annotation {
+    public constructor Marker()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class MyClass : MyInterface {
+    public constructor MyClass()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ fun execute(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface MyInterface {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract fun execute(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}