Remove never option in argument position

taiki-e · Aug 19, 2019 · b4e31cc · b4e31cc
1 parent 96e0134
commit b4e31cc
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Showing 7 changed files with 39 additions and 109 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 * Renamed `#[rec]` to `#[nested]`.
 
+* [Removed `never` option in argument position in favor of `#[enum_derive]` attribute.][48]
+
 * Added `"ops"` crate feature, and made `[std|core]::ops`'s `Deref`, `DerefMut`, `Index`, `IndexMut`, and `RangeBounds` traits optional.
 
 * Added `"convert"` crate feature, and made `[std|core]::convert`'s `AsRef` and `AsMut` traits optional.
@@ -14,6 +16,8 @@
 
 * Improved error messages.
 
+[48]: https://github.com/taiki-e/auto_enums/pull/48
+
 # 0.5.10 - 2019-08-15
 
 * Updated `proc-macro2`, `syn`, and `quote` to 1.0.

diff --git a/core/src/auto_enum/args.rs b/core/src/auto_enum/args.rs
@@ -74,38 +74,25 @@ macro_rules! error {
     };
 }
 
-pub(super) fn parse_group(group: TokenStream) -> Result<(Vec<Arg>, Option<String>, bool)> {
+pub(super) fn parse_group(group: TokenStream) -> Result<(Vec<Arg>, Option<String>)> {
     syn::parse2::<Group>(group).and_then(|group| parse_args(group.stream()))
 }
 
-pub(super) fn parse_args(args: TokenStream) -> Result<(Vec<Arg>, Option<String>, bool)> {
+pub(super) fn parse_args(args: TokenStream) -> Result<(Vec<Arg>, Option<String>)> {
     const ERR: &str = "expected one of `,`, `::`, or identifier, found ";
 
     let mut iter = args.into_iter();
     let mut args = Vec::new();
     let mut marker = None;
-    let mut never = false;
     while let Some(tt) = iter.next() {
         match tt {
-            TokenTree::Ident(i) => match &*i.to_string() {
-                "marker" => marker_opt(i, &mut iter, &mut args, &mut marker)?,
-                "never" => {
-                    match iter.next() {
-                        None => {}
-                        Some(TokenTree::Punct(ref p)) if p.as_char() == ',' => {}
-                        tt => {
-                            args.push(path_or_ident(i, tt, &mut iter)?);
-                            continue;
-                        }
-                    }
-
-                    if never {
-                        error!(i, "multiple `never` option")
-                    }
-                    never = true;
+            TokenTree::Ident(i) => {
+                if i == "marker" {
+                    marker_opt(i, &mut iter, &mut args, &mut marker)?;
+                } else {
+                    args.push(path_or_ident(i, iter.next(), &mut iter)?);
                 }
-                _ => args.push(path_or_ident(i, iter.next(), &mut iter)?),
-            },
+            }
             TokenTree::Punct(p) => match p.as_char() {
                 ',' => {}
                 ':' => args.push(parse_path(vec![p.into()], &mut iter)?),
@@ -115,7 +102,7 @@ pub(super) fn parse_args(args: TokenStream) -> Result<(Vec<Arg>, Option<String>,
         }
     }
 
-    Ok((args, marker, never))
+    Ok((args, marker))
 }
 
 fn parse_path(mut path: Vec<TokenTree>, iter: &mut IntoIter) -> Result<Arg> {

diff --git a/core/src/auto_enum/context.rs b/core/src/auto_enum/context.rs
@@ -42,7 +42,7 @@ pub(super) enum VisitLastMode {
     item_fn: `fn _() -> Fn*() { || {} }`
     */
     Closure,
-    /// `Stmt::Semi(..)` or `never` option - never visit last expr
+    /// `Stmt::Semi(..)` - never visit last expr
     Never,
 }
 
@@ -63,13 +63,7 @@ pub(super) struct Context {
 }
 
 impl Context {
-    fn new(
-        span: impl ToTokens,
-        args: Vec<Arg>,
-        marker: Option<String>,
-        never: bool,
-        root: bool,
-    ) -> Self {
+    fn new(span: impl ToTokens, args: Vec<Arg>, marker: Option<String>, root: bool) -> Self {
         Self {
             span: Some(span.into_token_stream()),
             args,
@@ -78,24 +72,18 @@ impl Context {
             // depth: 0,
             root,
             visit_mode: VisitMode::Default,
-            visit_last_mode: if never { VisitLastMode::Never } else { VisitLastMode::Default },
+            visit_last_mode: VisitLastMode::Default,
             other_attr: false,
             error: false,
         }
     }
 
-    pub(super) fn root(
-        span: impl ToTokens,
-        (args, marker, never): (Vec<Arg>, Option<String>, bool),
-    ) -> Self {
-        Self::new(span, args, marker, never, true)
+    pub(super) fn root(span: impl ToTokens, (args, marker): (Vec<Arg>, Option<String>)) -> Self {
+        Self::new(span, args, marker, true)
     }
 
-    pub(super) fn child(
-        span: impl ToTokens,
-        (args, marker, never): (Vec<Arg>, Option<String>, bool),
-    ) -> Self {
-        Self::new(span, args, marker, never, false)
+    pub(super) fn child(span: impl ToTokens, (args, marker): (Vec<Arg>, Option<String>)) -> Self {
+        Self::new(span, args, marker, false)
     }
 
     pub(super) fn span(&mut self) -> TokenStream {

diff --git a/src/lib.rs b/src/lib.rs
@@ -469,28 +469,6 @@
 //! # fn main() { let _ = foo(0); }
 //! ```
 //!
-//! You can also skip all branches by `never` option.
-//!
-//! ```rust
-//! # #![cfg_attr(feature = "try_trait", feature(try_trait))]
-//! # use auto_enums::auto_enum;
-//! #[auto_enum(never, Iterator)]
-//! fn foo(x: i32) -> impl Iterator<Item = i32> {
-//!     match x {
-//!         0 => loop {
-//!             return marker!(1..10);
-//!         },
-//!         1 => loop {
-//!             panic!()
-//!         },
-//!         _ => loop {
-//!             return marker!(vec![5, 10].into_iter());
-//!         },
-//!     }
-//! }
-//! # fn main() { let _ = foo(0); }
-//! ```
-//!
 //! ### Expression level marker (`marker!` macro)
 //!
 //! `#[auto_enum]` replaces `marker!` macros with variants.

diff --git a/tests/auto_enum.rs b/tests/auto_enum.rs
@@ -647,19 +647,6 @@ fn nightly() {
         assert_eq!(iter.sum::<i32>(), *x);
     }
 
-    // never opt
-    for (i, x) in ANS.iter().enumerate() {
-        #[auto_enum(never, Iterator)]
-        let iter = match i {
-            0 => marker!(1..8),
-            5..=10 => loop {
-                panic!()
-            },
-            _ => marker!(vec![1, 2, 0].into_iter()),
-        };
-        assert_eq!(iter.sum::<i32>(), *x);
-    }
-
     // never attr
     for (i, x) in ANS.iter().enumerate() {
         #[rustfmt::skip]

diff --git a/tests/ui/auto_enum/args.rs b/tests/ui/auto_enum/args.rs
@@ -24,14 +24,6 @@ fn unexpected_token_2(x: usize) -> impl Iterator<Item = i32> {
 mod marker {
     use auto_enums::auto_enum;
 
-    #[auto_enum(never, never, Iterator)] //~ ERROR multiple `never` option
-    fn multiple_never(x: usize) -> impl Iterator<Item = i32> {
-        match x {
-            0 => 1..=8,
-            _ => 0..2,
-        }
-    }
-
     #[auto_enum(marker{f}, Iterator)] //~ ERROR invalid delimiter
     fn marker_invalid_delimiter_1(x: usize) -> impl Iterator<Item = i32> {
         match x {

diff --git a/tests/ui/auto_enum/args.stderr b/tests/ui/auto_enum/args.stderr
@@ -10,65 +10,59 @@ error: expected one of `,`, `::`, or identifier, found `;`
 16 | #[auto_enum(Iterator,;)] //~ ERROR expected one of `,`, `::`, or identifier, found `;`
    |                      ^
 
-error: multiple `never` option
-  --> $DIR/args.rs:27:24
-   |
-27 |     #[auto_enum(never, never, Iterator)] //~ ERROR multiple `never` option
-   |                        ^^^^^
-
 error: invalid delimiter
-  --> $DIR/args.rs:35:23
+  --> $DIR/args.rs:27:23
    |
-35 |     #[auto_enum(marker{f}, Iterator)] //~ ERROR invalid delimiter
+27 |     #[auto_enum(marker{f}, Iterator)] //~ ERROR invalid delimiter
    |                       ^^^
 
 error: invalid delimiter
-  --> $DIR/args.rs:43:23
+  --> $DIR/args.rs:35:23
    |
-43 |     #[auto_enum(marker[f], Iterator)] //~ ERROR invalid delimiter
+35 |     #[auto_enum(marker[f], Iterator)] //~ ERROR invalid delimiter
    |                       ^^^
 
 error: multiple `marker` option
-  --> $DIR/args.rs:51:35
+  --> $DIR/args.rs:43:35
    |
-51 |     #[auto_enum(marker(f), marker(g), Iterator)] //~ ERROR multiple `marker` option
+43 |     #[auto_enum(marker(f), marker(g), Iterator)] //~ ERROR multiple `marker` option
    |                                   ^
 
 error: empty `marker` option
-  --> $DIR/args.rs:59:23
+  --> $DIR/args.rs:51:23
    |
-59 |     #[auto_enum(marker(), Iterator)] //~ ERROR empty `marker` option
+51 |     #[auto_enum(marker(), Iterator)] //~ ERROR empty `marker` option
    |                       ^^
 
 error: multiple identifier in `marker` option
-  --> $DIR/args.rs:67:27
+  --> $DIR/args.rs:59:27
    |
-67 |     #[auto_enum(marker(f, g), Iterator)] //~ ERROR multiple identifier in `marker` option
+59 |     #[auto_enum(marker(f, g), Iterator)] //~ ERROR multiple identifier in `marker` option
    |                           ^
 
 error: multiple identifier in `marker` option
-  --> $DIR/args.rs:75:26
+  --> $DIR/args.rs:67:26
    |
-75 |     #[auto_enum(marker(f t), Iterator)] //~ ERROR multiple identifier in `marker` option
+67 |     #[auto_enum(marker(f t), Iterator)] //~ ERROR multiple identifier in `marker` option
    |                          ^
 
 error: multiple `marker` option
-  --> $DIR/args.rs:83:34
+  --> $DIR/args.rs:75:34
    |
-83 |     #[auto_enum(marker=f, marker=g, Iterator)] //~ ERROR multiple `marker` option
+75 |     #[auto_enum(marker=f, marker=g, Iterator)] //~ ERROR multiple `marker` option
    |                                  ^
 
 error: expected an identifier, found `,`
-  --> $DIR/args.rs:91:24
+  --> $DIR/args.rs:83:24
    |
-91 |     #[auto_enum(marker=, Iterator)] //~ ERROR empty `marker` option
+83 |     #[auto_enum(marker=, Iterator)] //~ ERROR empty `marker` option
    |                        ^
 
 error: expected `,`, found `t`
-  --> $DIR/args.rs:99:26
+  --> $DIR/args.rs:91:26
    |
-99 |     #[auto_enum(marker=f t, Iterator)] //~ ERROR expected `,`, found `t`
+91 |     #[auto_enum(marker=f t, Iterator)] //~ ERROR expected `,`, found `t`
    |                          ^
 
-error: aborting due to 12 previous errors
+error: aborting due to 11 previous errors