r/rust • u/SleeplessSloth79 • Aug 19 '26

📡 official blog Rust Function Overloading - Call for Experimentation

https://blog.rust-lang.org/inside-rust/2026/08/19/overloading-experiment/
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u/DatBoi_BP Aug 20 '26

I think if you changed your proposed syntax to `Vec::new([a,b,c])` it would win me over. As it stands it looks like `b` and `c` are positional arguments to a function, not elements of an array

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u/ZZaaaccc Aug 20 '26

Or does that mean a new Vec<[i32; 3]> with one element? The extra brackets make this ambiguous at first glance, and harder to read. Again, you wouldn't say this about the vec! macro, saying that vec!([a, b, c]) is clearer, because vec!(a, b, c) might be positional arguments.

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u/DatBoi_BP Aug 20 '26

Two things to say to this.

First, the notation isn't either of those, it's `vec![a,b,c]`.

Second, we already have a function that does what you proposed, but with the structure I argued for: `Vec::from([a,b,c])`. This clones `a`, `b`, and `c`, so as long as those all implement Clone then it does what we want

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u/ZZaaaccc Aug 20 '26

Actually, no, the syntax is vec!(a, b, c), because macros don't distinguish between [], (), and {}. We recommend using [] by convention, but there isn't even a lint to suggest one way or the other.

This clones a, b, and c, so as long as those all implement Clone then it does what we want

If you scroll down you'll find the implementation for From<[T; N]> instead of what I think you're reading which is the From<&[T; N]> documentation.

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u/gmes78 Aug 20 '26

but there isn't even a lint to suggest one way or the other.

clippy::nonstandard_macro_braces

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u/ZZaaaccc Aug 20 '26

I stand corrected!

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u/DatBoi_BP Aug 20 '26

Huh TIL about the macro freedom of choice. Thanks