[K2] Support reporting of IMPLEMENTATION_BY_DELEGATION_IN_EXPECT_CLASS

^KT-59983

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/CommonDeclarationCheckers.kt

@@ -126,6 +126,7 @@ object CommonDeclarationCheckers : DeclarationCheckers() {
             FirOptInAnnotationClassChecker,
             FirCommonConstructorDelegationIssuesChecker,
             FirDelegationSuperCallInEnumConstructorChecker,
+            FirDelegationInExpectClassSyntaxChecker,
             FirDelegationInInterfaceSyntaxChecker,
             FirEnumClassSimpleChecker,
             FirLocalEntityNotAllowedChecker,

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/syntax/FirDelegationInExpectClassSyntaxChecker.kt

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2010-2021 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.syntax
+
+import org.jetbrains.kotlin.*
+import org.jetbrains.kotlin.diagnostics.DiagnosticReporter
+import org.jetbrains.kotlin.diagnostics.reportOn
+import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
+import org.jetbrains.kotlin.fir.declarations.FirRegularClass
+import org.jetbrains.kotlin.fir.declarations.utils.isExpect
+import org.jetbrains.kotlin.psi.KtClassOrObject
+import org.jetbrains.kotlin.psi.KtDelegatedSuperTypeEntry
+
+object FirDelegationInExpectClassSyntaxChecker : FirDeclarationSyntaxChecker<FirRegularClass, KtClassOrObject>() {
+
+    override fun isApplicable(element: FirRegularClass, source: KtSourceElement): Boolean = element.isExpect
+
+    override fun checkPsi(
+        element: FirRegularClass,
+        source: KtPsiSourceElement,
+        psi: KtClassOrObject,
+        context: CheckerContext,
+        reporter: DiagnosticReporter
+    ) {
+        for (superTypeRef in element.superTypeRefs) {
+            val superSource = superTypeRef.source ?: continue
+            val parent = superSource.psi?.parent as? KtDelegatedSuperTypeEntry ?: continue
+            reporter.reportOn(KtRealPsiSourceElement(parent), FirErrors.IMPLEMENTATION_BY_DELEGATION_IN_EXPECT_CLASS, context)
+        }
+    }
+
+    override fun checkLightTree(
+        element: FirRegularClass,
+        source: KtLightSourceElement,
+        context: CheckerContext,
+        reporter: DiagnosticReporter
+    ) {
+        for (superTypeRef in element.superTypeRefs) {
+            val superSource = superTypeRef.source ?: continue
+            val parent = superSource.treeStructure.getParent(superSource.lighterASTNode) ?: continue
+            if (parent.tokenType == KtNodeTypes.DELEGATED_SUPER_TYPE_ENTRY) {
+                reporter.reportOn(
+                    parent.toKtLightSourceElement(superSource.treeStructure),
+                    FirErrors.IMPLEMENTATION_BY_DELEGATION_IN_EXPECT_CLASS,
+                    context
+                )
+            }
+        }
+    }
+}

compiler/testData/diagnostics/tests/multiplatform/headerClass/inheritanceByDelegationInExpectClass.fir.kt

@@ -4,6 +4,6 @@
 interface A
 
 class B : A
-<!NO_ACTUAL_FOR_EXPECT!>expect class Foo(b: B) : A by b<!>
+<!NO_ACTUAL_FOR_EXPECT!>expect class Foo(b: B) : <!IMPLEMENTATION_BY_DELEGATION_IN_EXPECT_CLASS!>A by b<!><!>
 
-<!NO_ACTUAL_FOR_EXPECT!>expect class Bar : A by B()<!>
+<!NO_ACTUAL_FOR_EXPECT!>expect class Bar : <!IMPLEMENTATION_BY_DELEGATION_IN_EXPECT_CLASS!>A by B()<!><!>

compiler/testData/diagnostics/tests/multiplatform/headerClass/inheritanceByDelegationInExpectClass.ll.kt

@@ -4,6 +4,6 @@
 interface A
 
 class B : A
-expect class Foo(b: B) : A by b
+expect class Foo(b: B) : <!IMPLEMENTATION_BY_DELEGATION_IN_EXPECT_CLASS!>A by b<!>
 
-expect class Bar : A by B()
+expect class Bar : <!IMPLEMENTATION_BY_DELEGATION_IN_EXPECT_CLASS!>A by B()<!>