[FIR] Add RedundantModalityModifierChecker

compiler/fir/analysis-tests/testData/extendedCheckers/RedundantModalityModifierChecker.kt

@@ -0,0 +1,60 @@
+// Abstract
+abstract class Base {
+    // Redundant final
+    <!REDUNDANT_MODALITY_MODIFIER!>final<!> fun foo() {}
+    // Abstract
+    abstract fun bar()
+    // Open
+    open val gav = 42
+}
+
+class FinalDerived : Base() {
+    // Redundant final
+    override <!REDUNDANT_MODALITY_MODIFIER!>final<!> fun bar() {}
+    // Non-final member in final class
+    override open val gav = 13
+}
+// Open
+open class OpenDerived : Base() {
+    // Final
+    override final fun bar() {}
+    // Redundant open
+    override <!REDUNDANT_MODALITY_MODIFIER!>open<!> val gav = 13
+}
+// Redundant final
+<!REDUNDANT_MODALITY_MODIFIER!>final<!> class Final
+// Interface
+interface Interface {
+    // Redundant
+    <!REDUNDANT_MODALITY_MODIFIER!>abstract<!> fun foo()
+    // Redundant
+    private <!REDUNDANT_MODALITY_MODIFIER!>final<!> fun bar() {}
+    // Redundant
+    <!REDUNDANT_MODALITY_MODIFIER!>open<!> val gav: Int
+        get() = 42
+}
+// Derived interface
+interface Derived : Interface {
+    // Redundant
+    override <!REDUNDANT_MODALITY_MODIFIER!>open<!> fun foo() {}
+    // Redundant
+    <!REDUNDANT_MODALITY_MODIFIER!>final<!> class Nested
+}
+// Derived abstract class
+abstract class AbstractDerived1(override final val gav: Int) : Interface {
+    // Redundant
+    override <!REDUNDANT_MODALITY_MODIFIER!>open<!> fun foo() {}
+}
+// Derived abstract class
+abstract class AbstractDerived2 : Interface {
+    // Final
+    override final fun foo() {}
+    // Redundant
+    override <!REDUNDANT_MODALITY_MODIFIER!>open<!> val gav = 13
+}
+// Redundant abstract interface
+abstract interface AbstractInterface
+// Redundant final object
+<!REDUNDANT_MODALITY_MODIFIER!>final<!> object FinalObject
+// Open interface
+open interface OpenInterface

compiler/fir/analysis-tests/testData/extendedCheckers/RedundantModalityModifierChecker.txt

@@ -0,0 +1,103 @@
+FILE: RedundantModalityModifierChecker.kt
+    public abstract class Base : R|kotlin/Any| {
+        public constructor(): R|Base| {
+            super<R|kotlin/Any|>()
+        }
+
+        public final fun foo(): R|kotlin/Unit| {
+        }
+
+        public abstract fun bar(): R|kotlin/Unit|
+
+        public open val gav: R|kotlin/Int| = Int(42)
+            public get(): R|kotlin/Int|
+
+    }
+    public final class FinalDerived : R|Base| {
+        public constructor(): R|FinalDerived| {
+            super<R|Base|>()
+        }
+
+        public final override fun bar(): R|kotlin/Unit| {
+        }
+
+        public open override val gav: R|kotlin/Int| = Int(13)
+            public get(): R|kotlin/Int|
+
+    }
+    public open class OpenDerived : R|Base| {
+        public constructor(): R|OpenDerived| {
+            super<R|Base|>()
+        }
+
+        public final override fun bar(): R|kotlin/Unit| {
+        }
+
+        public open override val gav: R|kotlin/Int| = Int(13)
+            public get(): R|kotlin/Int|
+
+    }
+    public final class Final : R|kotlin/Any| {
+        public constructor(): R|Final| {
+            super<R|kotlin/Any|>()
+        }
+
+    }
+    public abstract interface Interface : R|kotlin/Any| {
+        public abstract fun foo(): R|kotlin/Unit|
+
+        private final fun bar(): R|kotlin/Unit| {
+        }
+
+        public open val gav: R|kotlin/Int|
+            public get(): R|kotlin/Int| {
+                ^ Int(42)
+            }
+
+    }
+    public abstract interface Derived : R|Interface| {
+        public open override fun foo(): R|kotlin/Unit| {
+        }
+
+        public final class Nested : R|kotlin/Any| {
+            public constructor(): R|Derived.Nested| {
+                super<R|kotlin/Any|>()
+            }
+
+        }
+
+    }
+    public abstract class AbstractDerived1 : R|Interface| {
+        public constructor(gav: R|kotlin/Int|): R|AbstractDerived1| {
+            super<R|kotlin/Any|>()
+        }
+
+        public final override val gav: R|kotlin/Int| = R|<local>/gav|
+            public get(): R|kotlin/Int|
+
+        public open override fun foo(): R|kotlin/Unit| {
+        }
+
+    }
+    public abstract class AbstractDerived2 : R|Interface| {
+        public constructor(): R|AbstractDerived2| {
+            super<R|kotlin/Any|>()
+        }
+
+        public final override fun foo(): R|kotlin/Unit| {
+        }
+
+        public open override val gav: R|kotlin/Int| = Int(13)
+            public get(): R|kotlin/Int|
+
+    }
+    public abstract interface AbstractInterface : R|kotlin/Any| {
+    }
+    public final object FinalObject : R|kotlin/Any| {
+        private constructor(): R|FinalObject| {
+            super<R|kotlin/Any|>()
+        }
+
+    }
+    public open interface OpenInterface : R|kotlin/Any| {
+    }