fix(compiler): shape re"..." no longer warns W0012 on its own synthesized null - #1997
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…ized null What: - A `shape name = re"..."` clause whose pattern has no unique rendering (e.g. `re"(-?\d+)\s+(-?\d+)"`) no longer emits `[W0012] null assigned where non-nullable 'onion.Function1[...]' is expected` on the shape clause -- a warning about a `null` the user never wrote. Why: the synthesized read-only shape passed a literal `null` printer to `Shapes::regex`, which the W0012 null-to-non-nullable check (by design, see NullToNonNullableSpec/NullToTypeVariableGenericSpec) correctly flags for user code but should never see from compiler- generated code. A new no-printer `Shapes.regex` overload lets the synthesized call skip the argument instead of passing `null` through Onion's type checker. Found while probing shape macros for gaps. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01S8s9sFYBxQuCjnkgmdRSde Co-Authored-By: 音羽ここね <kokone.ai.main@gmail.com>
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What
shape name = re"..."clause whose pattern has no unique rendering (e.g.re"(-?\d+)\s+(-?\d+)") no longer emits[W0012] null assigned where non-nullable 'onion.Function1[R, String]' is expectedon theshapeclause -- a warning about anullthe user never wrote.Why
The synthesized read-only shape passed a literal
nullprinter toShapes::regex. W0012's null-to-non-nullable check is correct, by design, for user code that writesnullinto a non-nullable generic position (seeNullToNonNullableSpec,NullToTypeVariableGenericSpec), but it should never fire on compiler-generated code the user has no control over. A new no-printerShapes.regexoverload lets the synthesized call skip the argument entirely instead of passingnullthrough Onion's type checker.Found while probing shape macros for gaps (every
shape ... = re"..."declaration with a non-invertible pattern was affected).Notes for reviewers
nullto the exactFunction1[R, String]type instead of adding an overload. That cast broke overload resolution forShapes::regex's genericT(a separate, pre-existing gap in generic-argument inference when an already-concretely-typed expression is passed at a type-variable position alongside a closure argument). The no-printer overload sidesteps that gap entirely rather than fixing it; the inference gap itself is not addressed here.Verification
ShapeRegexNonInvertibleNoWarningSpec(red before the fix, green after).SBT_OPTS="-Xmx10G -XX:+UseG1GC -Xss16m" sbt -Duser.language=en testFull-- 8351 passed, 0 failed, 2 canceled (pre-existing, unrelated).🤖 Generated with Claude Code
https://claude.ai/code/session_01S8s9sFYBxQuCjnkgmdRSde
Generated by Claude Code