unnecessary_force_analyzer.go

/*
 * Cadence-lint - The Cadence linter
 *
 * Copyright 2019-2022 Dapper Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package lint

import (
	"github.com/onflow/cadence/runtime/ast"
	"github.com/onflow/cadence/runtime/sema"
	"github.com/onflow/cadence/tools/analysis"
)

var UnnecessaryForceAnalyzer = (func() *analysis.Analyzer {

	elementFilter := []ast.Element{
		(*ast.ForceExpression)(nil),
	}

	return &analysis.Analyzer{
		Description: "Detects unnecessary uses of the force operator",
		Requires: []*analysis.Analyzer{
			analysis.InspectorAnalyzer,
		},
		Run: func(pass *analysis.Pass) interface{} {
			inspector := pass.ResultOf[analysis.InspectorAnalyzer].(*ast.Inspector)

			location := pass.Program.Location
			elaboration := pass.Program.Elaboration
			report := pass.Report

			inspector.Preorder(
				elementFilter,
				func(element ast.Element) {

					forceExpression, ok := element.(*ast.ForceExpression)
					if !ok {
						return
					}

					valueType := elaboration.ForceExpressionType(forceExpression)
					if valueType == nil {
						return
					}

					_, ok = valueType.(*sema.OptionalType)
					if !ok {
						report(
							analysis.Diagnostic{
								Location: location,
								Range:    ast.NewRangeFromPositioned(nil, element),
								Category: RemovalCategory,
								Message:  "unnecessary force operator",
							},
						)
					}
				},
			)

			return nil
		},
	}
})()

func init() {
	RegisterAnalyzer(
		"unnecessary-force",
		UnnecessaryForceAnalyzer,
	)
}