--- title: [RFC] [Discussion] Bound-Erased Generic Types | daily.dev description: A PHP internals mailing list discussion about a proposed RFC for bound-erased generic types in PHP. The RFC proposes adding generic type parameters to classes,... canonical: https://daily.dev/posts/rfc-discussion-bound-erased-generic-types-ub0f4mhum twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: [RFC] [Discussion] Bound-Erased Generic Types | daily.dev og:description: A PHP internals mailing list discussion about a proposed RFC for bound-erased generic types in PHP. The RFC proposes adding generic type parameters to classes,... og:url: https://daily.dev/posts/rfc-discussion-bound-erased-generic-types-ub0f4mhum og:image: https://api.daily.dev/og/posts/ub0f4MhuM.png og:image:alt: [RFC] [Discussion] Bound-Erased Generic Types og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # [RFC] [Discussion] Bound-Erased Generic Types **[externals.io](https://daily.dev/sources/externals)** · 284 min read · 0 upvotes · 0 comments ## Summary A PHP internals mailing list discussion about a proposed RFC for bound-erased generic types in PHP. The RFC proposes adding generic type parameters to classes, interfaces, traits, functions, methods, closures, and arrow functions, with bounds, defaults, and variance markers. Type parameters erase to their bound at runtime, while the pre-erasure form is preserved for Reflection and static analyzers. The discussion covers key design decisions including: type parameter ordering restrictions, intersection type constraints, arity validation (opt-in via turbofish syntax), diamond inheritance checks, the turbofish `::< >` syntax choice over alternatives, `+`/`-` variance markers vs `in`/`out` keywords, and the path toward future reified/runtime generics. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [\[RFC\] \[Discussion\] Bound-Erased Generic Types](https://daily.dev/posts/rfc-discussion-bound-erased-generic-types-1fq6lxtix) · externals.io · 0 upvotes · 0 comments - [\[RFC\] \[Discussion\] Bound-Erased Generic Types](https://daily.dev/posts/rfc-discussion-bound-erased-generic-types-twyg5s5ae) · externals.io · 0 upvotes · 0 comments - [\[RFC\] \[Discussion\] Bound-Erased Generic Types](https://daily.dev/posts/rfc-discussion-bound-erased-generic-types-heg1rsj6m) · externals.io · 0 upvotes · 0 comments --- Tags: [#php](https://daily.dev/tags/php) [View this post on daily.dev](https://daily.dev/posts/rfc-discussion-bound-erased-generic-types-ub0f4mhum) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"[RFC] [Discussion] Bound-Erased Generic Types","url":"https://daily.dev/posts/rfc-discussion-bound-erased-generic-types-ub0f4mhum","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/rfc-discussion-bound-erased-generic-types-ub0f4mhum"},"datePublished":"2026-06-08T15:28:04.784Z","dateModified":"2026-06-08T15:28:34.794Z","description":"A PHP internals mailing list discussion about a proposed RFC for bound-erased generic types in PHP. 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