compiler: Fix expression switch with non-last default
#4078
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Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## master #4078 +/- ##
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- Coverage 83.51% 83.47% -0.04%
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Files 351 351
Lines 42404 42395 -9
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- Hits 35412 35389 -23
- Misses 5249 5275 +26
+ Partials 1743 1731 -12 ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
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Turalchik
reviewed
Nov 18, 2025
According to https://go.dev/ref/spec#Expression_switches: > There can be at most one default case and it may appear anywhere in the "switch" statement. Previously, `default` statements executed even if they are followed by a matching `case`. Signed-off-by: Leonard Lyubich <[email protected]>
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Turalchik
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AnnaShaleva
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Dec 3, 2025
| last := len(n.Body.List) - 1 | ||
| for i := range last { | ||
| if n.Body.List[i].(*ast.CaseClause).List == nil { // early default | ||
| n.Body.List[i], n.Body.List[last] = n.Body.List[last], n.Body.List[i] |
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We need to check if this substitution affects generated debug info. Lines info stored in debug info for substituted default should match the source code.
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how can i check this?
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See how saveSequencePoint works, ensure that proper statement boundaries will be stored in the debug info file on compilation:
Line 128 in 93fe450
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Problem
i encountered this once while debugging a contract and spent a lot of time searching for the problem
Solution
first, swapping expressions as the most obvious. But it changes the input, and mutation is possible. Cloning is an option, but im gonna think about it some more