70 lines
1.6 KiB
Go
70 lines
1.6 KiB
Go
package checkers
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import (
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"go/ast"
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"go/types"
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"github.com/go-critic/checkers/internal/lintutil"
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"github.com/go-lintpack/lintpack"
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"github.com/go-lintpack/lintpack/astwalk"
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"github.com/go-toolsmith/astequal"
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)
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func init() {
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var info lintpack.CheckerInfo
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info.Name = "unlambda"
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info.Tags = []string{"style"}
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info.Summary = "Detects function literals that can be simplified"
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info.Before = `func(x int) int { return fn(x) }`
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info.After = `fn`
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collection.AddChecker(&info, func(ctx *lintpack.CheckerContext) lintpack.FileWalker {
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return astwalk.WalkerForExpr(&unlambdaChecker{ctx: ctx})
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})
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}
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type unlambdaChecker struct {
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astwalk.WalkHandler
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ctx *lintpack.CheckerContext
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}
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func (c *unlambdaChecker) VisitExpr(x ast.Expr) {
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fn, ok := x.(*ast.FuncLit)
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if !ok || len(fn.Body.List) != 1 {
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return
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}
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ret, ok := fn.Body.List[0].(*ast.ReturnStmt)
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if !ok || len(ret.Results) != 1 {
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return
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}
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result := lintutil.AsCallExpr(ret.Results[0])
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callable := qualifiedName(result.Fun)
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if callable == "" {
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return // Skip tricky cases; only handle simple calls
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}
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fnType := c.ctx.TypesInfo.TypeOf(fn)
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resultType := c.ctx.TypesInfo.TypeOf(result.Fun)
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if !types.Identical(fnType, resultType) {
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return
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}
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// Now check that all arguments match the parameters.
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n := 0
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for _, params := range fn.Type.Params.List {
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for _, id := range params.Names {
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if !astequal.Expr(id, result.Args[n]) {
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return
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}
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n++
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}
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}
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c.warn(fn, callable)
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}
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func (c *unlambdaChecker) warn(cause ast.Node, suggestion string) {
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c.ctx.Warn(cause, "replace `%s` with `%s`", cause, suggestion)
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}
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