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package sharedcheck
import (
"go/ast"
"go/types"
"honnef.co/go/tools/lint"
"honnef.co/go/tools/ssa"
)
func CheckRangeStringRunes(nodeFns map[ast.Node]*ssa.Function, j *lint.Job) {
fn := func(node ast.Node) bool {
rng, ok := node.(*ast.RangeStmt)
if !ok || !lint.IsBlank(rng.Key) {
return true
}
ssafn := nodeFns[rng]
if ssafn == nil {
return true
}
v, _ := ssafn.ValueForExpr(rng.X)
// Check that we're converting from string to []rune
val, _ := v.(*ssa.Convert)
if val == nil {
return true
}
Tsrc, ok := val.X.Type().(*types.Basic)
if !ok || Tsrc.Kind() != types.String {
return true
}
Tdst, ok := val.Type().(*types.Slice)
if !ok {
return true
}
TdstElem, ok := Tdst.Elem().(*types.Basic)
if !ok || TdstElem.Kind() != types.Int32 {
return true
}
// Check that the result of the conversion is only used to
// range over
refs := val.Referrers()
if refs == nil {
return true
}
// Expect two refs: one for obtaining the length of the slice,
// one for accessing the elements
if len(lint.FilterDebug(*refs)) != 2 {
// TODO(dh): right now, we check that only one place
// refers to our slice. This will miss cases such as
// ranging over the slice twice. Ideally, we'd ensure that
// the slice is only used for ranging over (without
// accessing the key), but that is harder to do because in
// SSA form, ranging over a slice looks like an ordinary
// loop with index increments and slice accesses. We'd
// have to look at the associated AST node to check that
// it's a range statement.
return true
}
j.Errorf(rng, "should range over string, not []rune(string)")
return true
}
for _, f := range j.Program.Files {
ast.Inspect(f, fn)
}
}
|
