#[derive(TryInto)] without #[try_into(repr)] silently doesn't do anything

[akonradi-signal]

The top-level implementation doesn't complain when there is no #[try_from] attribute at all:

derive_more/impl/src/try_from.rs

Lines 23 to 50 in 4de3ae7

	attr: ItemAttribute::parse_attrs(&input.attrs, &format_ident!("try_from"))?
	.map(|attr| {
	if matches!(attr.item, ItemAttribute::Types(_)) {
	Err(syn::Error::new(
	attr.span,
	"`#[try_from(repr(...))]` attribute is not supported yet",
	))
	} else {
	Ok(attr.item)
	}
	})
	.transpose()?,
	ident: input.ident.clone(),
	generics: input.generics.clone(),
	variants: data.variants.clone().into_iter().collect(),
	}
	.into_token_stream()),
	syn::Data::Union(data) => Err(syn::Error::new(
	data.union_token.span(),
	"`TryFrom` cannot be derived for unions",
	)),
	}
	}
	/// Representation of a [`TryFrom`] derive macro struct item attribute.
	///
	/// ```rust,ignore
	/// #[try_from(repr)]

But then the actual ToTokens impl doesn't actually do anything when the attribute is not present:

derive_more/impl/src/try_from.rs

Lines 78 to 80 in 4de3ae7

	if self.attr.is_none() {
	return;
	}

If the attribute is required, its absence should generate a compile error. If it's not required, then omitting it should not result in doing nothing.

[tyranron]

@akonradi-signal thanks! Good catch!