Type narrowing union types via return type of method call #1497
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tk0miya
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Feb 11, 2025
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tk0miya
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Feb 19, 2025
tk0miya
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This tries to narrow types unions by the return type of the method call. If the return type of the method is always truthy or falsy, the receiver type will be narrowed on the truthy branch and the falsy branch. This helps to narrow types via method definitions (ex. `#nil?`, `#present?`, `#blank?` and so on).
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@soutaro Thank you for reviewing. updated now. |
tk0miya
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Mar 8, 2025
This updates the return types of `#present?` and `#blank?` to true, false or bool to narrow the type of receiver. Since 1.10, Steep can narrow the type of receiver via the return type of the method when the type of receiver is union. For example, a receiver typed as will be narrowed to `String` on the `if present?` block, and be narrowed to `String | nil` on the `else` block because `String#present?` returns bool and `NilClass#present?` returns false. refs: * https://github.com/soutaro/steep/wiki/Release-Note-1.10 (unreleased yet) * soutaro/steep#1497
tk0miya
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Mar 8, 2025
This updates the return types of `#present?` and `#blank?` to narrow the type of receiver possibly. Since 1.10, Steep can narrow the type of receiver via the return type of the method when the type of receiver is union. For example, a receiver typed as will be narrowed to `String` on the `if present?` block, and be narrowed to `String | nil` on the `else` block because `String#present?` returns bool and `NilClass#present?` returns false. refs: * https://github.com/soutaro/steep/wiki/Release-Note-1.10 (unreleased yet) * soutaro/steep#1497
tk0miya
added a commit
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that referenced
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Mar 8, 2025
This updates the return types of `#present?` and `#blank?` to narrow the type of receiver possibly. Since 1.10, Steep can narrow the type of receiver via the return type of the method when the type of receiver is union. For example, a receiver typed as will be narrowed to `String` on the `if present?` block, and be narrowed to `String | nil` on the `else` block because `String#present?` returns bool and `NilClass#present?` returns false. ```ruby var = ... # String | nil if var.present? # var is narrowed to String else # var is narrowed to String | nil end ``` refs: * https://github.com/soutaro/steep/wiki/Release-Note-1.10 (unreleased yet) * soutaro/steep#1497
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Mar 22, 2025
This updates the return types of `#present?` and `#blank?` to narrow the type of receiver possibly. Since 1.10, Steep can narrow the type of receiver via the return type of the method when the type of receiver is union. For example, a receiver typed as will be narrowed to `String` on the `if present?` block, and be narrowed to `String | nil` on the `else` block because `String#present?` returns bool and `NilClass#present?` returns false. ```ruby var = ... # String | nil if var.present? # var is narrowed to String else # var is narrowed to String | nil end ``` refs: * https://github.com/soutaro/steep/wiki/Release-Note-1.10 (unreleased yet) * soutaro/steep#1497
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This tries to narrow types unions by the return type of the method call. If the return type of the method is always truthy or falsy, the receiver type will be narrowed on the truthy branch and the falsy branch.
This helps to narrow types via method definitions (ex.
#nil?,#present?,#blank?and so on).