x/tools/gopls/internal/analysis/stditerators: avoid introducing redundant variables

[adonovan]

Consider this stditerators modernization observed in CL 718504, a not uncommon pattern:

			for i := 0; i < T.NumFields(); i++ {
				if prev := T.Field(i); prev.Name() == r.to {

=>

			for field0 := range T.Fields() {
				if prev := field0; prev.Name() == r.to {

(Ignore the choice of name field0, as this is the topic of #76240.)

The assignment prev := field0 is redundant. The analyzer should recognize this pattern and choose the name prev in this case, deleting the IfStmt.Init statement.

[gabyhelp]

Related Issues

• x/tools/gopls/internal/analysis/stditerators: use fresh names only when necessary #76240

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[gopherbot]

Change https://go.dev/cl/719361 mentions this issue: go/analysis/passes/modernize: stditerators: better name heuristic

[gopherbot]

Change https://go.dev/cl/719360 mentions this issue: go/analysis/passes/modernize: forvar: handle "if v := v; cond {"

[gopherbot]

Change https://go.dev/cl/719321 mentions this issue: go/analysis/passes/modernize: stditerators: even better name heuristic