Prevent Hash#[]= on local variables from polluting parameter types
#363
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When `Hash#[]=` was called on a local variable inside a method, the assigned key/value types flowed back into the method's parameter type. This caused type explosion in real-world code like Action Pack's `url_for`, where the parameter type grew into a deeply nested recursive Hash type. Introduce HashAsetBox to handle `Hash#[]=` on local variables with flow-sensitive tracking. Instead of modifying the original hash type via backflow, it creates a new variable version with the updated type, so the parameter type only reflects types from call sites.
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@mame The default timeout for GitHub Actions is 360 minutes, so it would be helpful if you could cancel it before it wastes execution time. |
HashAsetBox.run0 created new Vertex objects on every invocation. Since Type memoization relies on object identity, each run produced "new" types that fed back through loop back-edges, preventing the graph from reaching a fixed point. Cache Vertex objects as instance variables so they are reused across runs, allowing Type memoization to recognize identical structures and the analysis to converge.
sinsoku
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Feb 8, 2026
TypeProf may cause infinite loops due to implementation mistakes, so set a timeout to avoid wasting CI execution time. ref: ruby#363 (comment)
mame
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Feb 9, 2026
TypeProf may cause infinite loops due to implementation mistakes, so set a timeout to avoid wasting CI execution time. ref: #363 (comment)
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When
Hash#[]=was called on a local variable inside a method, theassigned key/value types flowed back into the method's parameter type.
This caused type explosion in real-world code like Action Pack's
url_for, where the parameter type grew into a deeply nested recursiveHash type.
Introduce HashAsetBox to handle
Hash#[]=on local variables withflow-sensitive tracking. Instead of modifying the original hash type
via backflow, it creates a new variable version with the updated type,
so the parameter type only reflects types from call sites.
fixes #362