[FIR] Add RedundantSetterParameterType Checker

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

@@ -0,0 +1,28 @@
+
+@Target(AnnotationTarget.CLASS)
+annotation class Ann
+
+var x: Int
+    get() = 1
+    set(@Ann private x) { }
+
+
+var x: String = ""
+    set(param: <!REDUNDANT_SETTER_PARAMETER_TYPE!>String<!>) {
+        field = "$param "
+    }
+
+class My {
+    var y: Int = 1
+        set(param: <!REDUNDANT_SETTER_PARAMETER_TYPE!>Int<!>) {
+            field = param - 1
+        }
+
+    var z: Double = 3.14
+        private set
+
+    var w: Boolean = true
+        set(param) {
+            field = !param
+        }
+}

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

@@ -0,0 +1,40 @@
+FILE: RedundantSetterParameterTypeChecker.kt
+    @R|kotlin/annotation/Target|(vararg(Q|kotlin/annotation/AnnotationTarget|.R|kotlin/annotation/AnnotationTarget.CLASS|)) public final annotation class Ann : R|kotlin/Annotation| {
+        public constructor(): R|Ann| {
+            super<R|kotlin/Any|>()
+        }
+
+    }
+    public final var x: R|kotlin/Int|
+        public get(): R|kotlin/Int| {
+            ^ Int(1)
+        }
+        public set(@R|Ann|() x: R|kotlin/Int|): R|kotlin/Unit| {
+        }
+    public final var x: R|kotlin/String| = String()
+        public get(): R|kotlin/String|
+        public set(param: R|kotlin/String|): R|kotlin/Unit| {
+            F|/x| = <strcat>(R|<local>/param|.R|kotlin/Any.toString|(), String( ))
+        }
+    public final class My : R|kotlin/Any| {
+        public constructor(): R|My| {
+            super<R|kotlin/Any|>()
+        }
+
+        public final var y: R|kotlin/Int| = Int(1)
+            public get(): R|kotlin/Int|
+            public set(param: R|kotlin/Int|): R|kotlin/Unit| {
+                this@R|/My|.F|/My.y| = R|<local>/param|.R|kotlin/Int.minus|(Int(1))
+            }
+
+        public final var z: R|kotlin/Double| = Double(3.14)
+            public get(): R|kotlin/Double|
+            private set(value: R|kotlin/Double|): R|kotlin/Unit|
+
+        public final var w: R|kotlin/Boolean| = Boolean(true)
+            public get(): R|kotlin/Boolean|
+            public set(param: R|kotlin/Boolean|): R|kotlin/Unit| {
+                this@R|/My|.F|/My.w| = R|<local>/param|.R|kotlin/Boolean.not|()
+            }
+
+    }

compiler/fir/analysis-tests/tests/org/jetbrains/kotlin/fir/ExtendedFirDiagnosticsTestGenerated.java

@@ -48,6 +48,11 @@ public class ExtendedFirDiagnosticsTestGenerated extends AbstractExtendedFirDiag
         runTest("compiler/fir/analysis-tests/testData/extendedCheckers/RedundantReturnUnitTypeChecker.kt");
     }
 
+    @TestMetadata("RedundantSetterParameterTypeChecker.kt")
+    public void testRedundantSetterParameterTypeChecker() throws Exception {
+        runTest("compiler/fir/analysis-tests/testData/extendedCheckers/RedundantSetterParameterTypeChecker.kt");
+    }
+
     @TestMetadata("RedundantSingleExpressionStringTemplateChecker.kt")
     public void testRedundantSingleExpressionStringTemplateChecker() throws Exception {
         runTest("compiler/fir/analysis-tests/testData/extendedCheckers/RedundantSingleExpressionStringTemplateChecker.kt");

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/ExtendedDeclarationCheckers.kt

@@ -16,7 +16,8 @@ object ExtendedDeclarationCheckers : DeclarationCheckers() {
 
     override val memberDeclarationCheckers = listOf(
         RedundantModalityModifierChecker,
-        RedundantExplicitTypeChecker
+        RedundantExplicitTypeChecker,
+        RedundantSetterParameterTypeChecker
     )
 
     override val controlFlowAnalyserCheckers: List<FirControlFlowChecker> = listOf(

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

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.fir.analysis.checkers.extended
+
+import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
+import org.jetbrains.kotlin.fir.analysis.checkers.declaration.FirMemberDeclarationChecker
+import org.jetbrains.kotlin.fir.analysis.diagnostics.DiagnosticReporter
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.REDUNDANT_SETTER_PARAMETER_TYPE
+import org.jetbrains.kotlin.fir.declarations.FirMemberDeclaration
+import org.jetbrains.kotlin.fir.declarations.FirProperty
+import org.jetbrains.kotlin.fir.declarations.impl.FirDefaultPropertyAccessor
+
+object RedundantSetterParameterTypeChecker : FirMemberDeclarationChecker() {
+    override fun check(declaration: FirMemberDeclaration, context: CheckerContext, reporter: DiagnosticReporter) {
+        if (declaration !is FirProperty) return
+        val setter = declaration.setter ?: return
+        if (setter is FirDefaultPropertyAccessor) return
+        val valueParameter = setter.valueParameters.firstOrNull() ?: return
+        val propertyTypeSource = declaration.returnTypeRef.source
+        val setterParameterTypeSource = valueParameter.returnTypeRef.source ?: return
+        if (setterParameterTypeSource != propertyTypeSource) {
+            reporter.report(setterParameterTypeSource, REDUNDANT_SETTER_PARAMETER_TYPE)
+        }
+    }
+}

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt

@@ -107,4 +107,5 @@ object FirErrors {
     val REDUNDANT_CALL_OF_CONVERSION_METHOD by warning0<FirSourceElement, PsiElement>()
     val ARRAY_EQUALITY_OPERATOR_CAN_BE_REPLACED_WITH_EQUALS by warning0<FirSourceElement, PsiElement>()
     val EMPTY_RANGE by warning0<FirSourceElement, PsiElement>()
+    val REDUNDANT_SETTER_PARAMETER_TYPE by warning0<FirSourceElement, PsiElement>()
 }