[RFC FS-1151] Record spreads

[brianrourkeboll]

RFC for the record-to-record spreads subset of the approved language suggestion fsharp/fslang-suggestions#1253.

• Discussion thread (covers more than just records): [RFC FS-1151] Spread operator for F# #806
• Implementation: Record spreads: { ...expr }, { ...ty } dotnet/fsharp#18927

Click “Files changed” → “⋯” → “View file” for the rendered RFC.

[brianrourkeboll]

@dsyme This is ready for review.

[Happypig375]

type A = { a : int; b : int }
type B = { a : int } with member this.b = this.a + 1
let b = { a = 1 }
let a : A = { ...b } // should this work? how about properties brought in via type extension?
let c = {| ...b |} // and then this ignores properties?

[brianrourkeboll]

type A = { a : int; b : int }
type B = { a : int } with member this.b = this.a + 1
let b = { a = 1 }
let a : A = { ...b } // should this work? how about properties brought in via type extension?
let c = {| ...b |} // and then this ignores properties?

fslang-design/RFCs/FS-1151-record-spreads.md

Line 245 in f67b2df

Only record fields participate in spreads: other instance, static, or extension members are ignored.

And #806 (comment).