x/tools/gopls/internal/analyze/modernize: rangeint: transformation introduces invalid type

[adonovan]

The rangeint modernizer introduces bad type syntax when it decides the for-loop's limit expression requires an explicit conversion:

package mlkem

func TestFieldAdd(t *testing.T) {
	for a := fieldElement(0); a < q; a++ {
		for b := fieldElement(0); b < q; b++ {

func TestFieldAdd(t *testing.T) {
	for a := range mlkem.fieldElement(q) { // undefined: mlkem
		for b := range mlkem.fieldElement(q) {

See https://go.dev/cl/659155.

We need better testing.

[gabyhelp]

Related Issues

• x/tools/gopls/internal/analysis/modernize: rangeint should be silent when RHS of 'i < limit' depends on loop var #72726 (closed)
• x/tools/gopls/internal/analysis/modernize: rangeint: transformation unsound when loop variable is defined outside loop #73009 (closed)
• x/tools/gopls/internal/analysis/modernize: rangeint: transformation unsound when loop body has effects on iterated array #72917 (closed)
• x/tools/gopls: yet more modernizer bugs #71847 (closed)
• x/tools/gopls/internal/analysis/modernize: rangeint generates correct but not idiomatic transformation #71725 (closed)

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[gopherbot]

Change https://go.dev/cl/660815 mentions this issue: gopls/internal/analysis/modernize: don't add package when conversion type is defined in the same package