golang/go · error

no clauses

Error message

no clauses

What it means

Returned by parseScoreAdj when the score-adjustment flag string, split on "/", yields zero clauses. In practice strings.Split never returns a zero-length slice for a non-empty input (it always returns at least one element), so this branch only triggers when val is "". It guards the parser of the internal flag used to retune inline-heuristic adjustment scores.

Source

Thrown at src/cmd/compile/internal/inline/inlheur/scoring.go:121

	if err := parseScoreAdj(base.Debug.InlScoreAdj); err != nil {
		base.Fatalf("malformed -d=inlscoreadj argument %q: %v",
			base.Debug.InlScoreAdj, err)
	}
}

func adjStringToVal(s string) (scoreAdjustTyp, bool) {
	for adj := scoreAdjustTyp(1); adj < sentinelScoreAdj; adj <<= 1 {
		if adj.String() == s {
			return adj, true
		}
	}
	return 0, false
}

func parseScoreAdj(val string) error {
	clauses := strings.Split(val, "/")
	if len(clauses) == 0 {
		return fmt.Errorf("no clauses")
	}
	for _, clause := range clauses {
		elems := strings.Split(clause, ":")
		if len(elems) < 2 {
			return fmt.Errorf("clause %q: expected colon", clause)
		}
		if len(elems) != 2 {
			return fmt.Errorf("clause %q has %d elements, wanted 2", clause,
				len(elems))
		}
		adj, ok := adjStringToVal(elems[0])
		if !ok {
			return fmt.Errorf("clause %q: unknown adjustment", clause)
		}
		val, err := strconv.Atoi(elems[1])
		if err != nil {
			return fmt.Errorf("clause %q: malformed value: %v", clause, err)
		}

View on GitHub (pinned to b6b368adc5)

Solutions

1. Provide a non-empty adjustment string in the expected name:value[/name:value] form (e.g. panicPathAdj:40/initFuncAdj:20).
2. If the flag is optional, skip calling parseScoreAdj when the value is empty rather than parsing it.
3. Verify the adjustment names against the scoreAdjustTyp enum (panicPathAdj, initFuncAdj, inLoopAdj, ...).

// Skip parsing an unset flag value.
val := flag.Lookup("inlheuradjustments").Value.String()
if strings.TrimSpace(val) == "" {
    return nil // no adjustments to apply
}
return parseScoreAdj(val)

When it happens

Trigger: An internal flag value for inlheur score adjustments is parsed with parseScoreAdj and produces an empty clauses slice; effectively only when the flag value is the empty string passed through a code path that does not pre-filter it.

Common situations: Compiler development: passing -d=inlheuradjustments= (empty) or wiring the flag value from an unset environment variable. End users of released Go should never see this.

Related errors

• clause %q: expected colon
• clause %q has %d elements, wanted 2
• clause %q: unknown adjustment
• clause %q: malformed value: %v
• marshal error %v

AI-assisted analysis of golang/go@b6b368adc5 (2026-08-12). Data as JSON: /api/errors/36ff6225b4f11a47. Report an issue: GitHub.