[FIR] Fix redundant visibility checker

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

@@ -50,3 +50,23 @@ fun f() {
 }
 
 <!REDUNDANT_VISIBILITY_MODIFIER!>public<!> var baz = 0
+
+open class J {
+    protected val baz = 0
+    <!REDUNDANT_VISIBILITY_MODIFIER!>protected<!> get() = field * 2
+    var baf = 0
+    <!REDUNDANT_VISIBILITY_MODIFIER!>public<!> get() = 1
+    <!REDUNDANT_VISIBILITY_MODIFIER!>public<!> set(value) {
+        field = value
+    }
+
+    var buf = 0
+    private get() = 42
+    protected set(value) {
+        field = value
+    }
+
+    var bar = 0
+    get() = 3.1415926535
+    set(value) {}
+}

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

@@ -114,3 +114,37 @@ FILE: RedundantVisibilityModifierChecker.kt
     public final var baz: R|kotlin/Int| = Int(0)
         public get(): R|kotlin/Int|
         public set(value: R|kotlin/Int|): R|kotlin/Unit|
+    public open class J : R|kotlin/Any| {
+        public constructor(): R|J| {
+            super<R|kotlin/Any|>()
+        }
+
+        protected final val baz: R|kotlin/Int| = Int(0)
+            protected get(): R|kotlin/Int| {
+                ^ this@R|/J|.F|/J.baz|.R|kotlin/Int.times|(Int(2))
+            }
+
+        public final var baf: R|kotlin/Int| = Int(0)
+            public get(): R|kotlin/Int| {
+                ^ Int(1)
+            }
+            public set(value: R|kotlin/Int|): R|kotlin/Unit| {
+                this@R|/J|.F|/J.baf| = R|<local>/value|
+            }
+
+        public final var buf: R|kotlin/Int| = Int(0)
+            private get(): R|kotlin/Int| {
+                ^ Int(42)
+            }
+            protected set(value: R|kotlin/Int|): R|kotlin/Unit| {
+                this@R|/J|.F|/J.buf| = R|<local>/value|
+            }
+
+        public final var bar: R|kotlin/Int| = Int(0)
+            public get(): R|kotlin/Int| {
+                ^ Double(3.1415926535)
+            }
+            public set(value: R|kotlin/Int|): R|kotlin/Unit| {
+            }
+
+    }

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/extended/RedundantVisibilityModifierChecker.kt

@@ -23,27 +23,30 @@ object RedundantVisibilityModifierChecker : FirBasicDeclarationChecker() {
     override val isExtended = true
 
     override fun check(declaration: FirDeclaration, context: CheckerContext, reporter: DiagnosticReporter) {
-        if (declaration is FirPropertyAccessor && declaration.isGetter) return
-        if (declaration !is FirMemberDeclaration) return
         if (declaration is FirConstructor && declaration.source is FirFakeSourceElement<*>) return
+        if (declaration.source is FirFakeSourceElement<*>) return
+        if (
+            declaration !is FirMemberDeclaration
+            && !(declaration is FirPropertyAccessor
+                    && declaration.visibility == (context.containingDeclarations.last() as FirProperty).visibility)
+        ) return
 
         val modifierList = (declaration.source.getModifierList() as? FirPsiModifierList)?.modifierList ?: return
-        val visibilityModifier = modifierList.getVisibility()
+        val visibilityModifier = modifierList.getVisibility() ?: return
         val implicitVisibility = declaration.implicitVisibility(context)
-        val containingMemberDeclaration = context.containingDeclarations.getOrNull(1) as? FirMemberDeclaration
+        val containingMemberDeclaration = context.findClosest<FirMemberDeclaration>()
 
         val redundantVisibility = when {
             visibilityModifier == implicitVisibility -> implicitVisibility
             visibilityModifier == Visibilities.INTERNAL
                     && containingMemberDeclaration?.visibility == Visibilities.PRIVATE
-                    || declaration.visibility == Visibilities.INTERNAL -> Visibilities.INTERNAL
+                    || declaration.visibilityForDeclarationAndPropertyAccessor == Visibilities.INTERNAL -> Visibilities.INTERNAL
             else -> null
         } ?: return
 
         if (redundantVisibility == Visibilities.PUBLIC
-            && declaration is FirProperty
-            && declaration.isVar
-            && declaration.setter?.visibility.let { it != null && it != Visibilities.PUBLIC }
+            && declaration is FirPropertyAccessor
+            && declaration.source is FirFakeSourceElement<*>
         ) return
 
         val source = modifierList.visibilityModifier()?.toFirPsiSourceElement()
@@ -52,8 +55,10 @@ object RedundantVisibilityModifierChecker : FirBasicDeclarationChecker() {
 
     private fun FirDeclaration.implicitVisibility(context: CheckerContext): Visibility {
         return when {
-            this is FirPropertyAccessor && isSetter && status.isOverride -> {
-                this.visibility
+            this is FirPropertyAccessor && isSetter && status.isOverride -> this.visibility
+
+            this is FirPropertyAccessor -> {
+                context.findClosest<FirProperty>()?.visibility ?: Visibilities.DEFAULT_VISIBILITY
             }
 
             this is FirConstructor -> {
@@ -69,7 +74,7 @@ object RedundantVisibilityModifierChecker : FirBasicDeclarationChecker() {
             }
 
             this is FirSimpleFunction
-                    && context.containingDeclarations.getOrNull(1) is FirClass<*>
+                    && context.containingDeclarations.last() is FirClass<*>
                     && this.isOverride -> findFunctionVisibility(this, context)
 
             else -> Visibilities.DEFAULT_VISIBILITY
@@ -102,4 +107,11 @@ object RedundantVisibilityModifierChecker : FirBasicDeclarationChecker() {
         }
         return null
     }
+
+    private val FirDeclaration.visibilityForDeclarationAndPropertyAccessor
+        get() = when (this) {
+            is FirMemberDeclaration -> status.visibility
+            is FirPropertyAccessor -> status.visibility
+            else -> null
+        }
 }