FIR IDE: build KtJavaFieldSymbol only for Java fields

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/declarations/builder/FirFieldBuilder.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.fir.declarations.builder
 
 import kotlin.contracts.*
+import org.jetbrains.kotlin.fir.FirImplementationDetail
 import org.jetbrains.kotlin.fir.FirSession
 import org.jetbrains.kotlin.fir.FirSourceElement
 import org.jetbrains.kotlin.fir.builder.FirAnnotationContainerBuilder
@@ -51,6 +52,7 @@ open class FirFieldBuilder : FirAnnotationContainerBuilder {
     open var containerSource: DeserializedContainerSource? = null
     open var dispatchReceiverType: ConeKotlinType? = null
 
+    @OptIn(FirImplementationDetail::class)
     override fun build(): FirField {
         return FirFieldImpl(
             source,

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/declarations/impl/FirFieldImpl.kt

@@ -5,6 +5,7 @@
 
 package org.jetbrains.kotlin.fir.declarations.impl
 
+import org.jetbrains.kotlin.fir.FirImplementationDetail
 import org.jetbrains.kotlin.fir.FirSession
 import org.jetbrains.kotlin.fir.FirSourceElement
 import org.jetbrains.kotlin.fir.declarations.FirDeclarationAttributes
@@ -29,7 +30,7 @@ import org.jetbrains.kotlin.fir.visitors.*
  * DO NOT MODIFY IT MANUALLY
  */
 
-internal class FirFieldImpl(
+class FirFieldImpl @FirImplementationDetail constructor(
     override val source: FirSourceElement?,
     override val session: FirSession,
     override var resolvePhase: FirResolvePhase,

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/ImplementationConfigurator.kt

@@ -209,6 +209,7 @@ object ImplementationConfigurator : AbstractFirTreeImplementationConfigurator()
                 value = "!isVar"
                 withGetter = true
             }
+            publicImplementation()
 
             defaultNull("delegateFieldSymbol", "receiverTypeRef", "delegate", "getter", "setter", withGetter = true)
         }

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/KtSymbolByFirBuilder.kt

@@ -8,11 +8,12 @@ package org.jetbrains.kotlin.idea.frontend.api.fir
 import com.google.common.collect.MapMaker
 import com.intellij.openapi.project.Project
 import com.intellij.psi.search.GlobalSearchScope
-import org.jetbrains.kotlin.fir.FirElement
+import org.jetbrains.kotlin.fir.*
-import org.jetbrains.kotlin.fir.FirSession
 import org.jetbrains.kotlin.fir.declarations.*
+import org.jetbrains.kotlin.fir.declarations.impl.FirFieldImpl
 import org.jetbrains.kotlin.fir.declarations.synthetic.FirSyntheticProperty
 import org.jetbrains.kotlin.fir.resolve.calls.originalConstructorIfTypeAlias
+import org.jetbrains.kotlin.fir.java.declarations.FirJavaField
 import org.jetbrains.kotlin.fir.resolve.symbolProvider
 import org.jetbrains.kotlin.fir.resolve.getSymbolByLookupTag
 import org.jetbrains.kotlin.fir.resolve.inference.isFunctionalType
@@ -236,10 +237,18 @@ internal class KtSymbolByFirBuilder private constructor(
         }
 
 
-        // todo handle cases
         fun buildFieldSymbol(fir: FirField): KtFirJavaFieldSymbol {
+            if (!fir.isJavaFieldOrSubstitutionOverrideOfJavaField()) {
+                error("Could not build symbol for non-Java field symbol")
+            }
             return symbolsCache.cache(fir) { KtFirJavaFieldSymbol(fir, resolveState, token, this@KtSymbolByFirBuilder) }
         }
+
+        private fun FirField.isJavaFieldOrSubstitutionOverrideOfJavaField(): Boolean = when (this) {
+            is FirJavaField -> true
+            is FirFieldImpl -> (this as FirField).originalForSubstitutionOverride?.isJavaFieldOrSubstitutionOverrideOfJavaField() == true
+            else -> throwUnexpectedElementError(this)
+        }
     }
 
     inner class CallableSymbolBuilder {
@@ -309,7 +318,7 @@ internal class KtSymbolByFirBuilder private constructor(
         }
 
     }
-    
+
     companion object {
         private fun throwUnexpectedElementError(element: Any): Nothing {
             error("Unexpected ${element::class.simpleName}")