Propagate block return types to method return types#112
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Methods like `map` return generic types parameterized by block return values
(e.g., `[1,2].map { |x| x.to_s }` → `Array[String]`). Without this, the
type checker could not infer the element type of collections produced by
block-yielding methods, causing false positives on subsequent method calls.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Motivation
Methods like
mapreturn generic types parameterized by block return values (e.g.,[1,2].map { |x| x.to_s }→Array[String]). Without this propagation, the type checker could not infer the element type of collections produced by block-yielding methods, causing false positives on subsequent method calls like.upcase.Changes
BlockResultstruct to return block body's last expression vertex fromblocks.rsBlockReturnTypeBoxthat observes block return type and substitutes type variables in method return typesRbsTypeConverter::parseto handle generic types (e.g.,Array[Elem],Hash[K, V])is_type_variable_name/is_block_type_variable_nameas module-level functions and addresolve_return_typefor shared type variable resolutionSerializableMethodInfo::return_type()method (replaced byRbsTypeConverter::parse)Checked
cargo test --libpassesbundle exec rake testpasses🤖 Generated with Claude Code