FIR IDE: do not resolve whole firFile in completion

idea/idea-frontend-fir/idea-fir-low-level-api/src/org/jetbrains/kotlin/idea/fir/low/level/api/FirModuleResolveState.kt

@@ -39,6 +39,8 @@ abstract class FirModuleResolveState {
 
     abstract fun getOrBuildFirFor(element: KtElement, toPhase: FirResolvePhase): FirElement
 
+    abstract fun getFirFile(ktFile: KtFile): FirFile
+
     abstract fun getDiagnostics(element: KtElement): List<Diagnostic>
 
     // todo temporary, used only in completion
@@ -77,6 +79,9 @@ internal class FirModuleResolveStateImpl(
     override fun getOrBuildFirFor(element: KtElement, toPhase: FirResolvePhase): FirElement =
         elementBuilder.getOrBuildFirFor(element, currentModuleSourcesSession.cache, fileStructureCache)
 
+    override fun getFirFile(ktFile: KtFile): FirFile =
+        firFileBuilder.buildRawFirFileWithCaching(ktFile, currentModuleSourcesSession.cache)
+
     override fun getDiagnostics(element: KtElement): List<Diagnostic> =
         diagnosticsCollector.getDiagnosticsFor(element)
 

idea/idea-frontend-fir/idea-fir-low-level-api/src/org/jetbrains/kotlin/idea/fir/low/level/api/FirModuleResolveStateForCompletion.kt

@@ -47,6 +47,9 @@ internal class FirModuleResolveStateForCompletion(
         )
     }
 
+    override fun getFirFile(ktFile: KtFile): FirFile =
+        originalState.getFirFile(ktFile)
+
     override fun recordPsiToFirMappingsForCompletionFrom(fir: FirDeclaration, firFile: FirFile, ktFile: KtFile) {
         fir.accept(FirElementsRecorder(), completionMapping)
     }

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

@@ -66,9 +66,9 @@ internal class KtFirCompletionCandidateChecker(
         nameExpression: KtSimpleNameExpression,
         possibleExplicitReceiver: KtExpression?,
     ): Boolean {
-        val file = originalFile.getOrBuildFirOfType<FirFile>(firResolveState)
+        val file = firResolveState.getFirFile(originalFile)
         val explicitReceiverExpression = possibleExplicitReceiver?.getOrBuildFirOfType<FirExpression>(firResolveState)
-        val resolver = SingleCandidateResolver(firResolveState.firIdeSourcesSession, file)
+        val resolver = SingleCandidateResolver(firResolveState.currentModuleSourcesSession, file)
         val implicitReceivers = getImplicitReceivers(originalFile, file, nameExpression)
         for (implicitReceiverValue in implicitReceivers) {
             val resolutionParameters = ResolutionParameters(