Implement placeholder attribute to prevent multiple derive_wheres with different paths

CHANGELOG.md

@@ -6,7 +6,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 ### Added
-- Support [`ZeroizeOnDrop`](https://docs.rs/zeroize/1.5.0-pre/zeroize/trait.ZeroizeOnDrop.html).
+- Support [`ZeroizeOnDrop`](https://docs.rs/zeroize/1.5.0/zeroize/trait.ZeroizeOnDrop.html).
 
 ### Removed
 - **Breaking Change**: Remove support for `Zeroize(drop)`.

Cargo.toml

@@ -1,6 +1,6 @@
 [workspace]
 default-members = [""]
-members = ["", "ensure-no-std", "non-msrv-tests"]
+members = ["", "crate_", "ensure-no-std", "non-msrv-tests"]
 resolver = "2"
 
 [package]
@@ -32,14 +32,12 @@ quote = { version = "1", default-features = false }
 syn = { version = "1", default-features = false, features = [
 	"clone-impls",
 	"derive",
+	"extra-traits",
 	"full",
 	"parsing",
 	"printing",
 ] }
 
-[dev-dependencies]
-syn = { version = "1", default-features = false, features = ["extra-traits"] }
-
 [[test]]
 name = "util"
 path = "tests/util.rs"

README.md

@@ -228,7 +228,7 @@ Unions only support [`Clone`](https://doc.rust-lang.org/core/clone/trait.Clone.h
   [`unreachable`](https://doc.rust-lang.org/core/macro.unreachable.html).
 - `zeroize`: Allows deriving [`Zeroize`] and [`method@zeroize`] on [`Drop`](https://doc.rust-lang.org/core/ops/trait.Drop.html).
 - `zeroize-on-drop`: Allows deriving [`Zeroize`] and [`ZeroizeOnDrop`] and
-  requires [zeroize] v1.5.0-pre.
+  requires [zeroize] v1.5.0.
 
 ## MSRV
 
@@ -266,11 +266,11 @@ conditions.
 [CHANGELOG]: https://github.com/ModProg/derive-where/blob/main/CHANGELOG.md
 [LICENSE-MIT]: https://github.com/ModProg/derive-where/blob/main/LICENSE-MIT
 [LICENSE-APACHE]: https://github.com/ModProg/derive-where/blob/main/LICENSE-APACHE
-[zeroize]: https://crates.io/crates/zeroize/1.5.0-pre
+[zeroize]: https://crates.io/crates/zeroize/1.5.0
 [`Debug`]: https://doc.rust-lang.org/core/fmt/trait.Debug.html
 [`Default`]: https://doc.rust-lang.org/core/default/trait.Default.html
 [`Hash`]: https://doc.rust-lang.org/core/hash/trait.Hash.html
 [`Zeroize`]: https://docs.rs/zeroize/latest/zeroize/trait.Zeroize.html
-[`ZeroizeOnDrop`]: https://docs.rs/zeroize/1.5.0-pre/zeroize/trait.ZeroizeOnDrop.html
+[`ZeroizeOnDrop`]: https://docs.rs/zeroize/1.5.0/zeroize/trait.ZeroizeOnDrop.html
 [`method@zeroize`]: https://docs.rs/zeroize/latest/zeroize/trait.Zeroize.html#tymethod.zeroize
 [#27]: https://github.com/ModProg/derive-where/issues/27

crate_/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+edition = "2018"
+name = "crate_"
+publish = false
+version = "0.0.0"
+
+[features]
+nightly = ["derive-where_/nightly"]
+safe = ["derive-where_/safe"]
+zeroize = ["derive-where_/zeroize", "zeroize_"]
+zeroize-on-drop = ["derive-where_/zeroize-on-drop", "zeroize"]
+
+[dependencies]
+derive-where_ = { path = "..", package = "derive-where" }
+zeroize_ = { version = "1.5.0", package = "zeroize", default-features = false, optional = true }
+
+[lib]
+doctest = false
+test = false

crate_/src/lib.rs

@@ -0,0 +1,13 @@
+#![no_std]
+
+#[cfg(feature = "zeroize")]
+extern crate zeroize_ as zeroize;
+
+use core::marker::PhantomData;
+
+use derive_where_::derive_where;
+
+#[derive_where(Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd)]
+#[cfg_attr(feature = "zeroize", derive_where(Zeroize))]
+#[derive_where(crate = "derive_where_")]
+pub struct Test<T>(PhantomData<T>);

ensure-no-std/Cargo.toml

@@ -12,7 +12,7 @@ zeroize-on-drop = ["derive-where/zeroize-on-drop", "zeroize"]
 
 [dependencies]
 derive-where = { path = ".." }
-zeroize_ = { version = "1.5.0-pre", package = "zeroize", default-features = false, optional = true }
+zeroize_ = { version = "1.5.0", package = "zeroize", default-features = false, optional = true }
 
 [lib]
 doctest = false

non-msrv-tests/Cargo.toml

@@ -15,7 +15,7 @@ derive-where = { path = ".." }
 
 [dev-dependencies]
 trybuild = { version = "1", default-features = false }
-zeroize_ = { version = "1.5.0-pre", package = "zeroize", default-features = false }
+zeroize_ = { version = "1.5.0", package = "zeroize", default-features = false }
 
 [lib]
 doctest = false

non-msrv-tests/tests/ui/item.rs

@@ -8,6 +8,28 @@ struct NoOption<T>(PhantomData<T>);
 #[derive_where()]
 struct EmptyAttribute<T>(PhantomData<T>);
 
+#[derive_where(crate(derive_where_))]
+struct WrongCrateSyntax<T>(PhantomData<T>);
+
+#[derive_where(crate = "struct Test")]
+struct InvalidPath<T>(PhantomData<T>);
+
+// The error message here shows that `crate = ".."` should be in it's own
+// attribute instead of an error pointing out this is duplicate. This is not
+// ideal but much less complicated to implement.
+#[derive_where(crate = "derive_where_", crate = "derive_where_")]
+struct DuplicateCrate1<T>(PhantomData<T>);
+
+#[derive_where(crate = "derive_where_")]
+#[derive_where(crate = "derive_where_")]
+struct DuplicateCrate2<T>(PhantomData<T>);
+
+#[derive_where(crate = "derive_where_")]
+struct OnlyCrate<T>(PhantomData<T>);
+
+#[derive_where(crate = "::derive_where")]
+struct DefaultCrate<T>(PhantomData<T>);
+
 #[derive_where(Clone; T;)]
 struct SemiColonAtTheEnd<T, U>(T, PhantomData<U>);
 
@@ -26,4 +48,8 @@ struct MissingCommaBetweenGenerics<T, U, V>(T, PhantomData<(U, V)>);
 #[derive_where("Clone")]
 struct InvalidTrait<T>(PhantomData<T>);
 
+#[derive_where(Clone)]
+#[derive_where::derive_where(Copy)]
+struct QualifiedNotFirstMacro<T>(PhantomData<T>);
+
 fn main() {}

non-msrv-tests/tests/ui/item.stderr

@@ -14,38 +14,82 @@ error: empty `derive_where` found
   |
   = note: this error originates in the attribute macro `derive_where` (in Nightly builds, run with -Z macro-backtrace for more info)
 
+error: unexpected option syntax
+  --> tests/ui/item.rs:11:16
+   |
+11 | #[derive_where(crate(derive_where_))]
+   |                ^^^^^^^^^^^^^^^^^^^^
+
+error: expected path, expected identifier
+  --> tests/ui/item.rs:14:24
+   |
+14 | #[derive_where(crate = "struct Test")]
+   |                        ^^^^^^^^^^^^^
+
+error: the `crate` option has to be defined in it's own `#[derive_where(..)` attribute
+  --> tests/ui/item.rs:20:16
+   |
+20 | #[derive_where(crate = "derive_where_", crate = "derive_where_")]
+   |                ^^^^^
+
+error: duplicate `crate` option
+  --> tests/ui/item.rs:24:16
+   |
+24 | #[derive_where(crate = "derive_where_")]
+   |                ^^^^^^^^^^^^^^^^^^^^^^^
+
+error: no traits found to implement, use `#[derive_where(..)` to specify some
+  --> tests/ui/item.rs:28:1
+   |
+28 | struct OnlyCrate<T>(PhantomData<T>);
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: unnecessary path qualification, `::derive_where` is used by default
+  --> tests/ui/item.rs:30:24
+   |
+30 | #[derive_where(crate = "::derive_where")]
+   |                        ^^^^^^^^^^^^^^^^
+
 error: expected `,`
-  --> tests/ui/item.rs:11:24
+  --> tests/ui/item.rs:33:24
    |
-11 | #[derive_where(Clone; T;)]
+33 | #[derive_where(Clone; T;)]
    |                        ^
 
 error: expected type to bind to, expected one of: `for`, parentheses, `fn`, `unsafe`, `extern`, identifier, `::`, `<`, square brackets, `*`, `&`, `!`, `impl`, `_`, lifetime
-  --> tests/ui/item.rs:14:25
+  --> tests/ui/item.rs:36:25
    |
-14 | #[derive_where(Clone; T,,)]
+36 | #[derive_where(Clone; T,,)]
    |                         ^
 
 error: expected type to bind to, expected one of: `for`, parentheses, `fn`, `unsafe`, `extern`, identifier, `::`, `<`, square brackets, `*`, `&`, `!`, `impl`, `_`, lifetime
-  --> tests/ui/item.rs:17:23
+  --> tests/ui/item.rs:39:23
    |
-17 | #[derive_where(Clone; where)]
+39 | #[derive_where(Clone; where)]
    |                       ^^^^^
 
 error: expected `;` or `,
-  --> tests/ui/item.rs:20:22
+  --> tests/ui/item.rs:42:22
    |
-20 | #[derive_where(Clone Debug)]
+42 | #[derive_where(Clone Debug)]
    |                      ^^^^^
 
 error: expected `,`
-  --> tests/ui/item.rs:23:25
+  --> tests/ui/item.rs:45:25
    |
-23 | #[derive_where(Clone; T U)]
+45 | #[derive_where(Clone; T U)]
    |                         ^
 
 error: unexpected option syntax
-  --> tests/ui/item.rs:26:16
+  --> tests/ui/item.rs:48:16
    |
-26 | #[derive_where("Clone")]
+48 | #[derive_where("Clone")]
    |                ^^^^^^^
+
+error: `#[derive_where(..)` was already applied to this item before, this occurs when using a qualified path for any `#[derive_where(..)`s except the first
+  --> tests/ui/item.rs:51:1
+   |
+51 | #[derive_where(Clone)]
+   | ^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in the attribute macro `derive_where` (in Nightly builds, run with -Z macro-backtrace for more info)

non-msrv-tests/tests/ui/not-zeroize/item.stderr

@@ -1,34 +1,34 @@
-error: unsupported trait, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd
+error: unsupported trait, expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd
  --> tests/ui/not-zeroize/item.rs:5:16
   |
 5 | #[derive_where(skip_inner, Clone)]
   |                ^^^^^^^^^^
 
-error: unsupported trait syntax, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd
+error: unsupported trait syntax, expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd
  --> tests/ui/not-zeroize/item.rs:8:24
   |
 8 | #[derive_where(Debug = invalid; T)]
   |                        ^^^^^^^
 
-error: unsupported trait syntax, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd
+error: unsupported trait syntax, expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd
   --> tests/ui/not-zeroize/item.rs:11:16
    |
 11 | #[derive_where(,)]
    |                ^
 
-error: unsupported trait syntax, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd
+error: unsupported trait syntax, expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd
   --> tests/ui/not-zeroize/item.rs:14:16
    |
 14 | #[derive_where(,Clone)]
    |                ^
 
-error: unsupported trait syntax, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd
+error: unsupported trait syntax, expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd
   --> tests/ui/not-zeroize/item.rs:17:22
    |
 17 | #[derive_where(Clone,,)]
    |                      ^
 
-error: unsupported trait, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd
+error: unsupported trait, expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd
   --> tests/ui/not-zeroize/item.rs:20:16
    |
 20 | #[derive_where(T)]

non-msrv-tests/tests/ui/zeroize/item.stderr

@@ -1,34 +1,34 @@
-error: unsupported trait, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize, ZeroizeOnDrop
+error: unsupported trait, expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize, ZeroizeOnDrop
  --> tests/ui/zeroize/item.rs:5:16
   |
 5 | #[derive_where(skip_inner, Clone)]
   |                ^^^^^^^^^^
 
-error: unsupported trait syntax, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize, ZeroizeOnDrop
+error: unsupported trait syntax, expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize, ZeroizeOnDrop
  --> tests/ui/zeroize/item.rs:8:24
   |
 8 | #[derive_where(Debug = invalid; T)]
   |                        ^^^^^^^
 
-error: unsupported trait syntax, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize, ZeroizeOnDrop
+error: unsupported trait syntax, expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize, ZeroizeOnDrop
   --> tests/ui/zeroize/item.rs:11:16
    |
 11 | #[derive_where(,)]
    |                ^
 
-error: unsupported trait syntax, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize, ZeroizeOnDrop
+error: unsupported trait syntax, expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize, ZeroizeOnDrop
   --> tests/ui/zeroize/item.rs:14:16
    |
 14 | #[derive_where(,Clone)]
    |                ^
 
-error: unsupported trait syntax, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize, ZeroizeOnDrop
+error: unsupported trait syntax, expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize, ZeroizeOnDrop
   --> tests/ui/zeroize/item.rs:17:22
    |
 17 | #[derive_where(Clone,,)]
    |                      ^
 
-error: unsupported trait, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize, ZeroizeOnDrop
+error: unsupported trait, expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize, ZeroizeOnDrop
   --> tests/ui/zeroize/item.rs:20:16
    |
 20 | #[derive_where(T)]

non-msrv-tests/tests/ui/zeroize/zeroize.rs

@@ -17,9 +17,12 @@ struct WrongOptionSyntax2<T>(PhantomData<T>);
 struct WrongCrateSyntax<T>(PhantomData<T>);
 
 #[derive_where(Zeroize(crate = "struct Test"))]
-struct InvalidCrate<T>(PhantomData<T>);
+struct InvalidPath<T>(PhantomData<T>);
 
 #[derive_where(Zeroize(crate = "zeroize_", crate = "zeroize_"))]
 struct DuplicateCrate<T>(PhantomData<T>);
 
+#[derive_where(Zeroize(crate = "::zeroize"))]
+struct DefaultCrate<T>(PhantomData<T>);
+
 fn main() {}

non-msrv-tests/tests/ui/zeroize/zeroize.stderr

@@ -33,3 +33,9 @@ error: duplicate `crate` option
    |
 22 | #[derive_where(Zeroize(crate = "zeroize_", crate = "zeroize_"))]
    |                                            ^^^^^^^^^^^^^^^^^^
+
+error: unnecessary path qualification, `::zeroize` is used by default
+  --> tests/ui/zeroize/zeroize.rs:25:32
+   |
+25 | #[derive_where(Zeroize(crate = "::zeroize"))]
+   |                                ^^^^^^^^^^^