FIR IDE: introduce HLSpecifyExplicitTypeForCallableDeclarationIntention and HLRedundantUnitReturnTypeInspection

idea/idea-frontend-api/src/org/jetbrains/kotlin/idea/frontend/api/KtAnalysisSession.kt

@@ -85,6 +85,8 @@ abstract class KtAnalysisSession(final override val token: ValidityToken) : Vali
 
     val builtinTypes: KtBuiltinTypes get() = typeProvider.builtinTypes
 
+    fun KtType.approximateToPublicDenotable(): KtType? = typeProvider.approximateToPublicDenotable(this)
+
     fun KtClassOrObjectSymbol.buildSelfClassType(): KtType = typeProvider.buildSelfClassType(this)
 
     fun KtElement.getDiagnostics(): Collection<KtDiagnostic> = diagnosticProvider.getDiagnosticsForElement(this)

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

@@ -13,6 +13,8 @@ import org.jetbrains.kotlin.idea.frontend.api.types.KtType
 abstract class KtTypeProvider : KtAnalysisSessionComponent() {
     abstract val builtinTypes: KtBuiltinTypes
 
+    abstract fun approximateToPublicDenotable(type: KtType): KtType?
+
     abstract fun buildSelfClassType(symbol: KtClassOrObjectSymbol): KtType
 }