FIR checker: introduce member property checker

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

@@ -0,0 +1,120 @@
+/*
+ * 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.declaration
+
+import org.jetbrains.kotlin.descriptors.ClassKind
+import org.jetbrains.kotlin.descriptors.Visibilities
+import org.jetbrains.kotlin.fir.FirSourceElement
+import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
+import org.jetbrains.kotlin.fir.analysis.checkers.extended.report
+import org.jetbrains.kotlin.fir.analysis.diagnostics.DiagnosticReporter
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
+import org.jetbrains.kotlin.fir.declarations.*
+import org.jetbrains.kotlin.fir.declarations.impl.FirDefaultPropertyAccessor
+import org.jetbrains.kotlin.fir.expressions.FirExpression
+import org.jetbrains.kotlin.fir.symbols.impl.FirPropertyAccessorSymbol
+import org.jetbrains.kotlin.fir.types.FirImplicitTypeRef
+
+// See old FE's [DeclarationsChecker]
+object FirMemberPropertyChecker : FirBasicDeclarationChecker() {
+    override fun check(declaration: FirDeclaration, context: CheckerContext, reporter: DiagnosticReporter) {
+        if (declaration !is FirRegularClass) {
+            return
+        }
+        for (member in declaration.declarations) {
+            if (member is FirProperty) {
+                checkProperty(declaration, member, reporter)
+            }
+        }
+    }
+
+    private fun checkProperty(containingDeclaration: FirRegularClass, property: FirProperty, reporter: DiagnosticReporter) {
+        if (inInterface(containingDeclaration) &&
+            property.visibility == Visibilities.Private &&
+            !property.isAbstract &&
+            (property.getter == null || property.getter is FirDefaultPropertyAccessor)
+        ) {
+            property.source?.let { source ->
+                reporter.report(source, FirErrors.PRIVATE_PROPERTY_IN_INTERFACE)
+            }
+        }
+
+        if (property.isAbstract) {
+            if (!containingDeclaration.isAbstract && !containingDeclaration.isSealed && !inEnumClass(containingDeclaration)) {
+                property.source?.let { source ->
+                    reporter.report(source, FirErrors.ABSTRACT_PROPERTY_IN_NON_ABSTRACT_CLASS)
+                    return
+                }
+            }
+
+            if (property.delegate != null) {
+                property.delegate!!.source?.let {
+                    if (inInterface(containingDeclaration)) {
+                        reporter.report(FirErrors.DELEGATED_PROPERTY_IN_INTERFACE.on(it, property.delegate!!))
+                    } else {
+                        reporter.report(FirErrors.ABSTRACT_DELEGATED_PROPERTY.on(it, property.delegate!!))
+                    }
+                }
+            }
+
+            checkAccessor(property.getter, property.delegate) { src, symbol ->
+                reporter.report(FirErrors.ABSTRACT_PROPERTY_WITH_GETTER.on(src, symbol))
+            }
+            checkAccessor(property.setter, property.delegate) { src, symbol ->
+                if (symbol.fir.visibility == Visibilities.Private && property.visibility != Visibilities.Private) {
+                    reporter.report(FirErrors.PRIVATE_SETTER_FOR_ABSTRACT_PROPERTY.on(src, symbol))
+                } else {
+                    reporter.report(FirErrors.ABSTRACT_PROPERTY_WITH_SETTER.on(src, symbol))
+                }
+            }
+        }
+
+        checkPropertyInitializer(containingDeclaration, property, reporter)
+
+        if (property.isOpen) {
+            checkAccessor(property.setter, property.delegate) { src, symbol ->
+                if (symbol.fir.visibility == Visibilities.Private && property.visibility != Visibilities.Private) {
+                    reporter.report(FirErrors.PRIVATE_SETTER_FOR_OPEN_PROPERTY.on(src, symbol))
+                }
+            }
+        }
+    }
+
+    private fun checkPropertyInitializer(containingDeclaration: FirRegularClass, property: FirProperty, reporter: DiagnosticReporter) {
+        property.initializer?.source?.let {
+            if (property.isAbstract) {
+                reporter.report(FirErrors.ABSTRACT_PROPERTY_WITH_INITIALIZER.on(it, property.initializer!!))
+            } else if (inInterface(containingDeclaration)) {
+                reporter.report(FirErrors.PROPERTY_INITIALIZER_IN_INTERFACE.on(it, property.initializer!!))
+            }
+        }
+        if (property.isAbstract) {
+            if (property.initializer == null && property.delegate == null && property.returnTypeRef is FirImplicitTypeRef) {
+                property.source?.let {
+                    reporter.report(FirErrors.PROPERTY_WITH_NO_TYPE_NO_INITIALIZER.on(it, property.symbol))
+                }
+            }
+        }
+    }
+
+    private fun checkAccessor(
+        accessor: FirPropertyAccessor?,
+        delegate: FirExpression?,
+        report: (FirSourceElement, FirPropertyAccessorSymbol) -> Unit,
+    ) {
+        if (accessor != null && accessor !is FirDefaultPropertyAccessor && accessor.hasBody && delegate == null) {
+            accessor.source?.let {
+                report.invoke(it, accessor.symbol)
+            }
+        }
+    }
+
+    private fun inInterface(containingDeclaration: FirRegularClass): Boolean =
+        containingDeclaration.classKind == ClassKind.INTERFACE
+
+    private fun inEnumClass(containingDeclaration: FirRegularClass): Boolean =
+        containingDeclaration.classKind == ClassKind.ENUM_CLASS
+}

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

@@ -12,7 +12,9 @@ import org.jetbrains.kotlin.fir.FirEffectiveVisibility
 import org.jetbrains.kotlin.fir.FirSourceElement
 import org.jetbrains.kotlin.fir.declarations.FirClass
 import org.jetbrains.kotlin.fir.declarations.FirMemberDeclaration
+import org.jetbrains.kotlin.fir.expressions.FirExpression
 import org.jetbrains.kotlin.fir.symbols.AbstractFirBasedSymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirPropertyAccessorSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirPropertySymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirRegularClassSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirTypeParameterSymbol
@@ -147,6 +149,23 @@ object FirErrors {
     val LOCAL_OBJECT_NOT_ALLOWED by error1<FirSourceElement, KtNamedDeclaration, Name>(SourceElementPositioningStrategies.DECLARATION_NAME)
     val LOCAL_INTERFACE_NOT_ALLOWED by error1<FirSourceElement, KtNamedDeclaration, Name>(SourceElementPositioningStrategies.DECLARATION_NAME)
 
+    // Properties & accessors
+    val ABSTRACT_PROPERTY_IN_NON_ABSTRACT_CLASS by error0<FirSourceElement, KtModifierListOwner>(SourceElementPositioningStrategies.MODALITY_MODIFIER)
+    val PRIVATE_PROPERTY_IN_INTERFACE by error0<FirSourceElement, KtModifierListOwner>(SourceElementPositioningStrategies.VISIBILITY_MODIFIER)
+
+    val ABSTRACT_PROPERTY_WITH_INITIALIZER by error1<FirSourceElement, PsiElement, FirExpression>()
+    val PROPERTY_INITIALIZER_IN_INTERFACE by error1<FirSourceElement, PsiElement, FirExpression>()
+    val PROPERTY_WITH_NO_TYPE_NO_INITIALIZER by error1<FirSourceElement, PsiElement, FirPropertySymbol>()
+
+    val ABSTRACT_DELEGATED_PROPERTY by error1<FirSourceElement, PsiElement, FirExpression>()
+    val DELEGATED_PROPERTY_IN_INTERFACE by error1<FirSourceElement, PsiElement, FirExpression>()
+    // TODO: val ACCESSOR_FOR_DELEGATED_PROPERTY by error1<FirSourceElement, PsiElement, FirPropertyAccessorSymbol>()
+
+    val ABSTRACT_PROPERTY_WITH_GETTER by error1<FirSourceElement, PsiElement, FirPropertyAccessorSymbol>()
+    val ABSTRACT_PROPERTY_WITH_SETTER by error1<FirSourceElement, PsiElement, FirPropertyAccessorSymbol>()
+    val PRIVATE_SETTER_FOR_ABSTRACT_PROPERTY by error1<FirSourceElement, PsiElement, FirPropertyAccessorSymbol>()
+    val PRIVATE_SETTER_FOR_OPEN_PROPERTY by error1<FirSourceElement, PsiElement, FirPropertyAccessorSymbol>()
+
     // Control flow diagnostics
     val UNINITIALIZED_VARIABLE by error1<FirSourceElement, PsiElement, FirPropertySymbol>()
     val WRONG_INVOCATION_KIND by warning3<FirSourceElement, PsiElement, AbstractFirBasedSymbol<*>, EventOccurrencesRange, EventOccurrencesRange>()