57 lines
1.5 KiB
Go
57 lines
1.5 KiB
Go
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package sa4015
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import (
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"fmt"
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"go/types"
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"honnef.co/go/tools/analysis/callcheck"
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"honnef.co/go/tools/analysis/lint"
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"honnef.co/go/tools/go/ir"
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"honnef.co/go/tools/go/ir/irutil"
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"honnef.co/go/tools/go/types/typeutil"
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"honnef.co/go/tools/internal/passes/buildir"
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"golang.org/x/tools/go/analysis"
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)
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var SCAnalyzer = lint.InitializeAnalyzer(&lint.Analyzer{
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Analyzer: &analysis.Analyzer{
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Name: "SA4015",
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Requires: []*analysis.Analyzer{buildir.Analyzer},
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Run: callcheck.Analyzer(checkMathIntRules),
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},
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Doc: &lint.RawDocumentation{
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Title: `Calling functions like \'math.Ceil\' on floats converted from integers doesn't do anything useful`,
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Since: "2017.1",
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Severity: lint.SeverityWarning,
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MergeIf: lint.MergeIfAll,
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},
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})
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var Analyzer = SCAnalyzer.Analyzer
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var checkMathIntRules = map[string]callcheck.Check{
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"math.Ceil": pointlessIntMath,
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"math.Floor": pointlessIntMath,
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"math.IsNaN": pointlessIntMath,
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"math.Trunc": pointlessIntMath,
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"math.IsInf": pointlessIntMath,
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}
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func pointlessIntMath(call *callcheck.Call) {
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if ConvertedFromInt(call.Args[0].Value) {
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call.Invalid(fmt.Sprintf("calling %s on a converted integer is pointless", irutil.CallName(call.Instr.Common())))
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}
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}
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func ConvertedFromInt(v callcheck.Value) bool {
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conv, ok := v.Value.(*ir.Convert)
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if !ok {
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return false
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}
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return typeutil.NewTypeSet(conv.X.Type()).All(func(t *types.Term) bool {
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b, ok := t.Type().Underlying().(*types.Basic)
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return ok && b.Info()&types.IsInteger != 0
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})
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}
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