12.0.0-rc.3

🐛 Bug fix

• Fix @directive on function level with async and multiple parameters. #7977
• Fix fatal error for external with @as. #7978

💅 Polish

• Rewatch: plain output when not running in tty. #7970
• Streamline rewatch help texts. #7973
• Rewatch: Reduced build progress output from 7 steps to 3 for cleaner, less verbose logging. #7971

🏠 Internal

• Clean up usage of Ast_uncurried helpers. #7987

12.0.0-rc.2

💥 Breaking Change

• Replace binary operators with F#-style ~~~, ^^^, &&&, |||. #7894

🐛 Bug fix

• Fix: use configured Jsx module for constraining component return type. #7945
• Undeprecate Js_OO module since it is still used with the @this attribute. #7955
• Fix crash when using bitwise not (~~~) on an incompatible type. #7965

🏠 Internal

• JSX PPX: use React.component instead of React.componentLike for externals. #7952

12.0.0-rc.1

💅 Polish

• Improve circular dependency errors, and make sure they end up in the compiler log so the editor tooling can surface them. #7940
• JSX PPX: add Jsx.element return constraint. #7939

🏠 Internal

• Use AST nodes with locations for fn arguments in the typed tree. #7873

12.0.0-beta.14

💥 Breaking Change

• Removed rescript legacy subcommand in favor of separate rescript-legacy binary. #7928
• Add comparison function for Error in Result.equal and compare. #7933
• Rewatch: "type": "dev" and dev-dependencies will be compiled by default for local packages. The --dev flag no longer does anything. #7934

🐛 Bug fix

• Prevent lockfile creation when project folder is missing. #7927
• Fix parameter type / return type ambiguity error for unit case. #7930

💅 Polish

• ReScript cli: do not show build command options in the root help. #7715
• Deprecate reanalyze @raises in favor of @throws. #7932

🏠 Internal

• CI: run macOS builds on macOS 15. #7935

12.0.0-beta.13

🐛 Bug fix

• Fix result examples. #7914
• Make inline record fields that overlap with a variant's tag a compile error. #7875

💅 Polish

• Keep track of compiler info during build. #7889
• Improve option optimization for constants. #7913
• Option optimization: do not create redundant local vars. #7915
• Js output: remove superfluous newline after every if. #7920
• Rewatch: Traverse upwards for package resolution in single context projects. #7896
• Rewatch: Add --warn-error flag to build. #7916

12.0.0-beta.12

💥 Breaking Change

• Make experimental-features kebap-case in compiler config like the other fields. #7891

🚀 New Feature

• Add littleEndian feature for DataView to Stdlib. #7881
• Add mapOkAsync, mapErrorAsync, flatMapOkAsync and flatMapErrorAsync for async results to Stdlib. #7906

🐛 Bug fix

• Include -runtime-path as bsc argument when generating .mlmap file. #7888

💅 Polish

• Add (dev-)dependencies to build schema. #7892
• Dedicated error for dict literal spreads. #7901
• Dedicated error message for when mixing up : and = in various positions. #7900

12.0.0-beta.11

💥 Breaking Change

• Have String.charCodeAt return option<int>; add String.charCodeAtUnsafe. #7877
• Remove support of JSX children spread. #7869

🚀 New Feature

• Add Array.filterMapWithIndex to Stdlib. #7876

🐛 Bug fix

• Fix code generation for emojis in polyvars and labels. #7853
• Add reset to experimental_features to correctly reset playground. #7868
• Fix crash with @get on external of type unit => 'a. #7866
• Fix record type spreads in inline records. #7859

💅 Polish

• Reactivate optimization for length of array literals. #7872
• Float.isNaN: use Number.isNaN instead of global isNaN. #7874

🏠 Internal

• Playground: Add config options for experimental features and jsx preserve mode. #7865
• Clean up tests. #7861 #7871
• Add -runtime-path flag to bsc (and bsb), we are detecting the location of @rescript/runtime in cli/rescript.js based on runtime module resolution. #7858

12.0.0-beta.10

🚀 New Feature

• Support mapping more standard library types automatically to TS types via gentype, without requiring shims. #7842

🐛 Bug fix

• Show Stdlib.TypedArray completions for typed arrays. #7827
• Show Stdlib.Null and Stdlib.Nullable completions for Stdlib.null<'a> and Stdlib.nullable<'a> types, respectively. #7826
• Fix generation of interfaces for module types containing multiple type constraints. #7825
• JSX preserve mode: fix "make is not a valid component name". #7831
• Rewatch: include parser arguments of experimental features. #7836
• Stop mangling tagged templates and backquoted strings. #7841
• JSX v4: fix arity mismatch for @react.component with React.forwardRef. #7845

💅 Polish

• Improve error message for trying to define a type inside a function. #7843
• Refactor CLI to use spawn for better signal handling in watch mode. #7844

12.0.0-beta.9

💥 Breaking Change

• Extract ReScript runtime files from main rescript package to separate @rescript/runtime package. #7796
• Remove @rescript/std (in favor of @rescript/runtime). #7811

🚀 New Feature

• Add support for ArrayBuffer and typed arrays to @unboxed. #7788
• Experimental: Add let? syntax for unwrapping and propagating errors/none as early returns for option/result types. #7582
• Add support for shipping features as experimental, including configuring what experimental features are enabled in rescript.json. #7582

🐛 Bug fix

• Fix JS regex literal parsing in character classes. #7790
• Fix creating interface for functions with upper bounded polymorphic args. #7786

💅 Polish

• Make parser less strict around leading attributes. #7787
• Dedicated error message for ternary type mismatch. #7804
• Dedicated error message for passing a braced ident to something expected to be a record. #7806
• Hint about partial application when missing required argument in function call. #7807
• More autocomplete improvements involving modules and module types. #7795
• Autocomplete @react.componentWithProps attribute. #7812
• Add some missing iframe attributes to domProps. #7813
• Polish error message for inline record escaping scope. #7808
• Formatter: Change placement of closing > in JSX. #7803

🏠 Internal

• Build runtime with rewatch on Windows, too. #7794

12.0.0-beta.7

🚀 New Feature

• Add markdown divider between module doc and module type in hover information. #7775
• Show docstrings before type expansions on hover. #7774
• Autocomplete (and improved hovers) for first-class module unpacks. #7780

🐛 Bug fix

• Preserve @as(...) decorator on record fields when creating interface. #7779
• Fix parse error with nested record types and attributes on the field name that has the nested record type. #7781
• Fix ppx resolution with package inside monorepo. #7776
• Fix 'Unbound module type' errors that occurred when trying to async import modules. #7783

💅 Polish

• Allow skipping the leading pipe in variant definition with a leading constructor with an attribute. #7782
• Better error message (and recovery) when using a keyword as a record field name. #7784