Skip bot type in typecheck to fix false errors on return/next#389
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mame merged 1 commit intoruby:masterfrom Feb 25, 2026
Merged
Skip bot type in typecheck to fix false errors on return/next#389mame merged 1 commit intoruby:masterfrom
mame merged 1 commit intoruby:masterfrom
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When a method body ends with a `return` (or a branch contains one), the implicit return value of the body includes `bot` (bottom type). Because `bot` is a subtype of all types, typecheck should not reject it. Previously each typecheck implementation iterated over every type in the vertex including `bot`, which caused spurious diagnostics like "expected: bool; actual: bot". Add `next if ty.is_a?(Type::Bot)` to all leaf typecheck methods in sig_type.rb so that `bot` is uniformly skipped during type checking. Fixes ruby#377
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When a method body ends with a
return(or a branch contains one), the implicit return value of the body includesbot(bottom type). Becausebotis a subtype of all types, typecheck should not reject it. Previously each typecheck implementation iterated over every type in the vertex includingbot, which caused spurious diagnostics like "expected: bool; actual: bot".Add
next if ty.is_a?(Type::Bot)to all leaf typecheck methods in sig_type.rb so thatbotis uniformly skipped during type checking.Fixes #377