From 4404e5f036c2f0be2dfeb846af68cab16ceab636 Mon Sep 17 00:00:00 2001
From: Roman Efremov <roman.efremov@jetbrains.com>
Date: Thu, 14 Sep 2023 17:22:37 +0200
Subject: [PATCH] [K2] Refactor: extract conditions in
 `FirExpectConsistencyChecker`

...to separate methods.

After the change each diagnostic report has its own condition,
independent from others, so you don't have to keep in mind
"we're in else branch, so this is already not a FirConstructor
and also it either top-level or inside classs".
This makes changes in next commits more clear and verifiable.

`isTopLevelOrInsideClass` condition for
`getConstructorDelegationCall` is not needed, because
constructor is always inside class.

^KT-59899
---
 .../FirExpectConsistencyChecker.kt            | 45 ++++++++++++-------
 1 file changed, 30 insertions(+), 15 deletions(-)

diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirExpectConsistencyChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirExpectConsistencyChecker.kt
index 74c3b0073f6..cfafdf2b31b 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirExpectConsistencyChecker.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirExpectConsistencyChecker.kt
@@ -15,6 +15,7 @@ import org.jetbrains.kotlin.fir.declarations.*
 import org.jetbrains.kotlin.fir.declarations.utils.hasBody
 import org.jetbrains.kotlin.fir.declarations.utils.isExpect
 import org.jetbrains.kotlin.fir.declarations.utils.visibility
+import org.jetbrains.kotlin.fir.expressions.FirDelegatedConstructorCall
 
 // See old FE's [DeclarationsChecker]
 object FirExpectConsistencyChecker : FirBasicDeclarationChecker() {
@@ -24,7 +25,7 @@ object FirExpectConsistencyChecker : FirBasicDeclarationChecker() {
 
         val isTopLevel = context.containingDeclarations.size == 1
         val lastClass = context.containingDeclarations.lastOrNull() as? FirClass
-        val isInsideClass = lastClass != null
+        val isTopLevelOrInsideClass = isTopLevel || lastClass != null
 
         if (declaration is FirAnonymousInitializer) {
             if (lastClass?.isExpect == true) {
@@ -33,27 +34,41 @@ object FirExpectConsistencyChecker : FirBasicDeclarationChecker() {
             return
         }
 
-        if (
-            declaration !is FirMemberDeclaration ||
-            !isTopLevel && !isInsideClass ||
-            !declaration.isExpect
-        ) {
+        if (declaration !is FirMemberDeclaration || !declaration.isExpect) {
             return
         }
 
-        if (declaration is FirConstructor) {
-            if (!declaration.isPrimary) {
-                val delegatedConstructorSource = declaration.delegatedConstructor?.source
-                if (delegatedConstructorSource?.kind !is KtFakeSourceElementKind) {
-                    reporter.reportOn(delegatedConstructorSource, FirErrors.EXPECTED_CLASS_CONSTRUCTOR_DELEGATION_CALL, context)
-                }
-            }
-        } else if (Visibilities.isPrivate(declaration.visibility)) {
+        getConstructorDelegationCall(declaration)?.let { delegatedConstructor ->
+            reporter.reportOn(delegatedConstructor.source, FirErrors.EXPECTED_CLASS_CONSTRUCTOR_DELEGATION_CALL, context)
+        }
+
+        if (isProhibitedPrivateDeclaration(declaration, isTopLevelOrInsideClass)) {
             reporter.reportOn(source, FirErrors.EXPECTED_PRIVATE_DECLARATION, context)
         }
 
-        if (declaration is FirFunction && declaration.hasBody) {
+        if (isProhibitedDeclarationWithBody(declaration, isTopLevelOrInsideClass)) {
             reporter.reportOn(source, FirErrors.EXPECTED_DECLARATION_WITH_BODY, context)
         }
     }
+
+    private fun getConstructorDelegationCall(declaration: FirMemberDeclaration): FirDelegatedConstructorCall? {
+        if (declaration is FirConstructor) {
+            if (!declaration.isPrimary) {
+                val delegatedConstructor = declaration.delegatedConstructor
+                val delegatedConstructorSource = delegatedConstructor?.source
+                if (delegatedConstructorSource?.kind !is KtFakeSourceElementKind) {
+                    return delegatedConstructor
+                }
+            }
+        }
+        return null
+    }
+
+    private fun isProhibitedPrivateDeclaration(declaration: FirMemberDeclaration, isTopLevelOrInsideClass: Boolean): Boolean {
+        return isTopLevelOrInsideClass && declaration !is FirConstructor && Visibilities.isPrivate(declaration.visibility)
+    }
+
+    private fun isProhibitedDeclarationWithBody(declaration: FirMemberDeclaration, isTopLevelOrInsideClass: Boolean): Boolean {
+        return isTopLevelOrInsideClass && declaration is FirFunction && declaration.hasBody
+    }
 }