[FIR] Add kind to diagnostics reported by RawFirBuilder

compiler/fir/tree/src/org/jetbrains/kotlin/fir/diagnostics/FirSimpleDiagnostic.kt

@@ -5,4 +5,13 @@
 
 package org.jetbrains.kotlin.fir.diagnostics
 
-class FirSimpleDiagnostic(override val reason: String) : FirDiagnostic()
+class FirSimpleDiagnostic(override val reason: String, val kind: DiagnosticKind = DiagnosticKind.Other) : FirDiagnostic()
+
+enum class DiagnosticKind {
+    Syntax,
+    ReturnNotAllowed,
+    UnresolvedLabel,
+    IllegalConstExpression,
+    ConstructorInObject,
+    Other
+}

compiler/fir/tree/src/org/jetbrains/kotlin/fir/expressions/FirExpressionUtil.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.fir.expressions
 
 import org.jetbrains.kotlin.fir.FirSourceElement
+import org.jetbrains.kotlin.fir.diagnostics.FirDiagnostic
 import org.jetbrains.kotlin.fir.diagnostics.FirSimpleDiagnostic
 import org.jetbrains.kotlin.fir.expressions.impl.FirConstExpressionImpl
 import org.jetbrains.kotlin.fir.expressions.impl.FirErrorExpressionImpl
@@ -24,8 +25,8 @@ inline val FirAnnotationCall.coneClassLikeType: ConeClassLikeType?
 inline val FirAnnotationCall.classId: ClassId?
     get() = coneClassLikeType?.lookupTag?.classId
 
-fun <T> FirConstExpressionImpl(source: FirSourceElement?, kind: IrConstKind<T>, value: T?, errorReason: String): FirExpression =
-    value?.let { FirConstExpressionImpl(source, kind, it) } ?: FirErrorExpressionImpl(source, FirSimpleDiagnostic(errorReason))
+fun <T> FirConstExpressionImpl(source: FirSourceElement?, kind: IrConstKind<T>, value: T?, diagnostic: FirDiagnostic): FirExpression =
+    value?.let { FirConstExpressionImpl(source, kind, it) } ?: FirErrorExpressionImpl(source, diagnostic)
 
 inline val FirTypeOperatorCall.argument: FirExpression get() = arguments.first()
 
@@ -37,8 +38,7 @@ fun FirExpression.toResolvedCallableSymbol(): FirCallableSymbol<*>? {
     return toResolvedCallableReference()?.resolvedSymbol as FirCallableSymbol<*>?
 }
 
-fun FirErrorLoop(source: FirSourceElement?, reason: String): FirErrorLoop {
-    val diagnostic = FirSimpleDiagnostic(reason)
+fun FirErrorLoop(source: FirSourceElement?, diagnostic: FirDiagnostic): FirErrorLoop {
     return FirErrorLoopImpl(source, diagnostic).apply {
         condition = FirErrorExpressionImpl(source, diagnostic)
     }