ErrorOnForceUnwrap.swift

ErrorOnForceUnwrap.swift

// Copyright 2018 Google LLC.
// SPDX-License-Identifier: Apache-2.0

import Foundation
import SwiftSyntax

public class DiagnoseForceUnwraps: SyntaxVisitor {
  public let engine: DiagnosticEngine

  public let file: URL

  public init(file: URL, diagnosticEngine: DiagnosticEngine) {
    self.file = file
    self.engine = diagnosticEngine
  }

  override public func visit(_ node: ForcedValueExprSyntax) {
    let location = node.exclamationMark.startLocation(in: file)

    engine.diagnose(.noForceUnwrap, location: location) {
      let expressionRange = node.expression.sourceRange(in: self.file)
      $0.highlight(expressionRange)
    }

    super.visit(node.expression)
  }
}

extension Diagnostic.Message {
  public static let noForceUnwrap =
    Diagnostic.Message(.error, "force unwrapping is not allowed")
}

func main() throws {
  let engine = DiagnosticEngine()

  engine.addConsumer(PrintingDiagnosticConsumer())

  let testURL = URL(fileURLWithPath: CommandLine.arguments[1])
  let testFile = try SourceFileSyntax.parse(testURL)

  let diagnoseForceUnwraps = DiagnoseForceUnwraps(
    file: testURL,
    diagnosticEngine: engine
  )

  diagnoseForceUnwraps.visit(testFile)
}

do {
  try main()
} catch {
  print("error: \(error)")
  exit(-1)
}