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Minor fixes to the semantic subtyping blog post (#720)

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docs/_posts/2022-10-31-luau-semantic-subtyping.md
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@ -66,8 +66,8 @@ Syntactic subtyping is a syntax-directed recursive algorithm. The interesting ca
* Reflexivity: `T` is a subtype of `T` * Reflexivity: `T` is a subtype of `T`
* Intersection L: `(T₁ & … & Tⱼ)` is a subtype of `U` whenever some of the `Tᵢ` are subtypes of `U` * Intersection L: `(T₁ & … & Tⱼ)` is a subtype of `U` whenever some of the `Tᵢ` are subtypes of `U`
* Union L: `(T₁ | … | Tⱼ)` is a subtype of `U` whenever all of the `Tᵢ` are subtypes of `U` * Union L: `(T₁ | … | Tⱼ)` is a subtype of `U` whenever all of the `Tᵢ` are subtypes of `U`
* Intersection R: `T` is a subtype of `(U₁ & … & Uⱼ)` whenever `T` is a subtype of some of the `Uᵢ` * Intersection R: `T` is a subtype of `(U₁ & … & Uⱼ)` whenever `T` is a subtype of all of the `Uᵢ`
* Union R: `T` is a subtype of `(U₁ | … | Uⱼ)` whenever `T` is a subtype of all of the `Uᵢ`. * Union R: `T` is a subtype of `(U₁ | … | Uⱼ)` whenever `T` is a subtype of some of the `Uᵢ`.
For example: For example:
@ -262,6 +262,10 @@ Semantic subtyping has removed one source of false positives, but we still have
The quest to remove spurious red squiggles continues! The quest to remove spurious red squiggles continues!
## Acknowledgments
Thanks to Giuseppe Castagna and Ben Greenman for helpful comments on drafts of this post.
## Further reading ## Further reading
If you want to find out more about Luau and semantic subtyping, you might want to check out… If you want to find out more about Luau and semantic subtyping, you might want to check out…
@ -274,8 +278,9 @@ If you want to find out more about Luau and semantic subtyping, you might want t
* Giuseppe Castagna, *Covariance and Contravariance*, Logical Methods in Computer Science 16(1), 2022. <https://arxiv.org/abs/1809.01427> * Giuseppe Castagna, *Covariance and Contravariance*, Logical Methods in Computer Science 16(1), 2022. <https://arxiv.org/abs/1809.01427>
* Giuseppe Castagna and Alain Frisch, *A gentle introduction to semantic subtyping*, Proc. Principles and practice of declarative programming (PPDP), pp 198–208, 2005. <https://doi.org/10.1145/1069774.1069793> * Giuseppe Castagna and Alain Frisch, *A gentle introduction to semantic subtyping*, Proc. Principles and practice of declarative programming (PPDP), pp 198–208, 2005. <https://doi.org/10.1145/1069774.1069793>
* Giuseppe Castagna, Mickaël Laurent, Kim Nguyễn, Matthew Lutze, *On Type-Cases, Union Elimination, and Occurrence Typing*, Principles of Programming Languages (POPL), 2022. <https://doi.org/10.1145/3498674> * Giuseppe Castagna, Mickaël Laurent, Kim Nguyễn, Matthew Lutze, *On Type-Cases, Union Elimination, and Occurrence Typing*, Principles of Programming Languages (POPL), 2022. <https://doi.org/10.1145/3498674>
* Sam Tobin-Hochstadt and Matthias Felleisen, *Logical types for untyped languages*. International Conference on Functional Programming (ICFP), 2010. https://doi.org/10.1145/1863543.1863561 * Giuseppe Castagna, *Programming with union, intersection, and negation types*, 2022. <https://arxiv.org/abs/2111.03354>
* José Valim, *My Future with Elixir: set-theoretic types*, 2022. https://elixir-lang.org/blog/2022/10/05/my-future-with-elixir-set-theoretic-types/ * Sam Tobin-Hochstadt and Matthias Felleisen, *Logical types for untyped languages*. International Conference on Functional Programming (ICFP), 2010. <https://doi.org/10.1145/1863543.1863561>
* José Valim, *My Future with Elixir: set-theoretic types*, 2022. <https://elixir-lang.org/blog/2022/10/05/my-future-with-elixir-set-theoretic-types/>
Some other languages which support semantic subtyping… Some other languages which support semantic subtyping…