Fable 5.10.0 released!

NewsBot · 16 July 2026 21:19

Fable 5.10.0 has been released.

Features

(beam) Support Environment.CurrentDirectory and GetEnvironmentVariable (#4801) (55b9d560)

(beam) Support setting Environment.CurrentDirectory (#4783) (7b2a262f)

(rust) Various codegen and runtime improvements (#4781) (ae10cd2c)

Cast bool to integer types; support ** via .powf

Add Decimal.IsInteger/IsEvenInteger/IsOddInteger/IsCanonical

Fix two-switch decision trees dispatching to the wrong target

Fix reference-typed match bindings panicking via mem::zeroed

Fix string and non-ident option pattern matches emitting invalid Rust
match arms

Fix Convert.ToXxx(bool)

Fix Char.ToUpper/ToLower truncating multi-char case mappings

Fix Random.nextDouble panic message

Fix Map.find/tryFind panicking on reference-typed values

Bug Fixes

(all) Skip translating unreachable branch of constant-condition if/then/else (#4799) (53c06de1)

(python) Make the assert_not_equal failure message describe the failure (#4778) (721fb437)

View changes on Github

Link: Release 5.10.0 · fable-compiler/Fable · GitHub