Rollup merge of #62068 - ia0:fix_meta_var, r=petrochenkov

Fix meta-variable binding errors in macros

The errors are either:
- The meta-variable used in the right-hand side is not bound (or defined) in the
  left-hand side.
- The meta-variable used in the right-hand side does not repeat with the same
  kleene operator as its binder in the left-hand side. Either it does not repeat
  enough, or it uses a different operator somewhere.

This change should have no semantic impact.

Found by https://github.com/rust-lang/rust/pull/62008

src/libcore/fmt/mod.rs

@@ -2070,19 +2070,19 @@ fn fmt(&self, f: &mut Formatter<'_>) -> Result { Pointer::fmt(self, f) }
     () => ();
     ( $($name:ident,)+ ) => (
         #[stable(feature = "rust1", since = "1.0.0")]
-        impl<$($name:Debug),*> Debug for ($($name,)*) where last_type!($($name,)+): ?Sized {
+        impl<$($name:Debug),+> Debug for ($($name,)+) where last_type!($($name,)+): ?Sized {
             #[allow(non_snake_case, unused_assignments)]
             fn fmt(&self, f: &mut Formatter<'_>) -> Result {
                 let mut builder = f.debug_tuple("");
-                let ($(ref $name,)*) = *self;
+                let ($(ref $name,)+) = *self;
                 $(
                     builder.field(&$name);
-                )*
+                )+
 
                 builder.finish()
             }
         }
-        peel! { $($name,)* }
+        peel! { $($name,)+ }
     )
 }
 

src/libcore/hash/mod.rs

@@ -617,11 +617,11 @@ fn hash<H: Hasher>(&self, _state: &mut H) {}
 
         ( $($name:ident)+) => (
             #[stable(feature = "rust1", since = "1.0.0")]
-            impl<$($name: Hash),*> Hash for ($($name,)*) where last_type!($($name,)+): ?Sized {
+            impl<$($name: Hash),+> Hash for ($($name,)+) where last_type!($($name,)+): ?Sized {
                 #[allow(non_snake_case)]
                 fn hash<S: Hasher>(&self, state: &mut S) {
-                    let ($(ref $name,)*) = *self;
-                    $($name.hash(state);)*
+                    let ($(ref $name,)+) = *self;
+                    $($name.hash(state);)+
                 }
             }
         );

src/libcore/iter/traits/accum.rs

@@ -72,10 +72,10 @@ fn product<I: Iterator<Item=&'a $a>>(iter: I) -> $a {
     ($($a:ty)*) => (
         integer_sum_product!(@impls 0, 1,
                 #[stable(feature = "iter_arith_traits", since = "1.12.0")],
-                $($a)+);
+                $($a)*);
         integer_sum_product!(@impls Wrapping(0), Wrapping(1),
                 #[stable(feature = "wrapping_iter_arith", since = "1.14.0")],
-                $(Wrapping<$a>)+);
+                $(Wrapping<$a>)*);
     );
 }
 

src/libcore/macros.rs

@@ -15,7 +15,7 @@
         $crate::panic!($msg)
     );
     ($fmt:expr, $($arg:tt)+) => ({
-        $crate::panicking::panic_fmt(format_args!($fmt, $($arg)*),
+        $crate::panicking::panic_fmt(format_args!($fmt, $($arg)+),
                                      &(file!(), line!(), __rust_unstable_column!()))
     });
 }
@@ -558,7 +558,7 @@
 #[stable(feature = "rust1", since = "1.0.0")]
 macro_rules! unimplemented {
     () => (panic!("not yet implemented"));
-    ($($arg:tt)+) => (panic!("not yet implemented: {}", format_args!($($arg)*)));
+    ($($arg:tt)+) => (panic!("not yet implemented: {}", format_args!($($arg)+)));
 }
 
 /// Indicates unfinished code.
@@ -617,7 +617,7 @@
 #[unstable(feature = "todo_macro", issue = "59277")]
 macro_rules! todo {
     () => (panic!("not yet implemented"));
-    ($($arg:tt)+) => (panic!("not yet implemented: {}", format_args!($($arg)*)));
+    ($($arg:tt)+) => (panic!("not yet implemented: {}", format_args!($($arg)+)));
 }
 
 /// Creates an array of [`MaybeUninit`].

src/libcore/ptr/mod.rs

@@ -2725,12 +2725,12 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 
 macro_rules! fnptr_impls_args {
     ($($Arg: ident),+) => {
-        fnptr_impls_safety_abi! { extern "Rust" fn($($Arg),*) -> Ret, $($Arg),* }
-        fnptr_impls_safety_abi! { extern "C" fn($($Arg),*) -> Ret, $($Arg),* }
-        fnptr_impls_safety_abi! { extern "C" fn($($Arg),* , ...) -> Ret, $($Arg),* }
-        fnptr_impls_safety_abi! { unsafe extern "Rust" fn($($Arg),*) -> Ret, $($Arg),* }
-        fnptr_impls_safety_abi! { unsafe extern "C" fn($($Arg),*) -> Ret, $($Arg),* }
-        fnptr_impls_safety_abi! { unsafe extern "C" fn($($Arg),* , ...) -> Ret, $($Arg),* }
+        fnptr_impls_safety_abi! { extern "Rust" fn($($Arg),+) -> Ret, $($Arg),+ }
+        fnptr_impls_safety_abi! { extern "C" fn($($Arg),+) -> Ret, $($Arg),+ }
+        fnptr_impls_safety_abi! { extern "C" fn($($Arg),+ , ...) -> Ret, $($Arg),+ }
+        fnptr_impls_safety_abi! { unsafe extern "Rust" fn($($Arg),+) -> Ret, $($Arg),+ }
+        fnptr_impls_safety_abi! { unsafe extern "C" fn($($Arg),+) -> Ret, $($Arg),+ }
+        fnptr_impls_safety_abi! { unsafe extern "C" fn($($Arg),+ , ...) -> Ret, $($Arg),+ }
     };
     () => {
         // No variadic functions with 0 parameters

src/libproc_macro/bridge/rpc.rs

@@ -59,7 +59,7 @@ fn decode(r: &mut Reader<'_>, s: &mut S) -> Self {
         }
     };
     (enum $name:ident $(<$($T:ident),+>)? { $($variant:ident $(($field:ident))*),* $(,)? }) => {
-        impl<S, $($($T: Encode<S>),+)?> Encode<S> for $name $(<$($T),+>)* {
+        impl<S, $($($T: Encode<S>),+)?> Encode<S> for $name $(<$($T),+>)? {
             fn encode(self, w: &mut Writer, s: &mut S) {
                 // HACK(eddyb): `Tag` enum duplicated between the
                 // two impls as there's no other place to stash it.
@@ -79,8 +79,8 @@ mod tag {
             }
         }
 
-        impl<S, $($($T: for<'s> DecodeMut<'a, 's, S>),+)*> DecodeMut<'a, '_, S>
-            for $name $(<$($T),+>)*
+        impl<S, $($($T: for<'s> DecodeMut<'a, 's, S>),+)?> DecodeMut<'a, '_, S>
+            for $name $(<$($T),+>)?
         {
             fn decode(r: &mut Reader<'a>, s: &mut S) -> Self {
                 // HACK(eddyb): `Tag` enum duplicated between the

src/librustc/middle/weak_lang_items.rs

@@ -147,7 +147,7 @@ pub fn is_weak_lang_item(&self, item_def_id: DefId) -> bool {
         let lang_items = self.lang_items();
         let did = Some(item_def_id);
 
-        $(lang_items.$name() == did)||+
+        $(lang_items.$name() == did)||*
     }
 }
 

src/librustc_codegen_llvm/builder.rs

@@ -110,7 +110,7 @@ impl HasCodegen<'tcx> for Builder<'_, 'll, 'tcx> {
             unsafe {
                 llvm::$llvm_capi(self.llbuilder, $($arg,)* UNNAMED)
             }
-        })*
+        })+
     }
 }
 

src/librustc_data_structures/indexed_vec.rs

@@ -423,7 +423,7 @@ fn decode<D: Decoder>(d: &mut D) -> Result<Self, D::Error> {
     (@derives      [$($derives:ident,)*]
      @attrs        [$(#[$attrs:meta])*]
      @type         [$type:ident]
-     @max          [$_max:expr]
+     @max          [$max:expr]
      @vis          [$v:vis]
      @debug_format [$debug_format:tt]
                    $(#[doc = $doc:expr])*

src/librustc_lint/types.rs

@@ -219,7 +219,7 @@ fn get_type_suggestion(t: Ty<'_>, val: u128, negative: bool) -> Option<String> {
                             return Some(format!("{:?}", $itypes))
                         })*
                         None
-                    },)*
+                    },)+
                     _ => None
                 }
             }

src/librustc_target/spec/mod.rs

@@ -119,19 +119,19 @@ fn to_json(&self) -> Json {
     ($((($($flavor:tt)*), $string:expr),)*) => (
         impl LinkerFlavor {
             pub const fn one_of() -> &'static str {
-                concat!("one of: ", $($string, " ",)+)
+                concat!("one of: ", $($string, " ",)*)
             }
 
             pub fn from_str(s: &str) -> Option<Self> {
                 Some(match s {
-                    $($string => $($flavor)*,)+
+                    $($string => $($flavor)*,)*
                     _ => return None,
                 })
             }
 
             pub fn desc(&self) -> &str {
                 match *self {
-                    $($($flavor)* => $string,)+
+                    $($($flavor)* => $string,)*
                 }
             }
         }

src/libserialize/serialize.rs

@@ -739,33 +739,33 @@ fn decode<D: Decoder>(d: &mut D) -> Result<Result<T1, T2>, D::Error> {
 macro_rules! tuple {
     () => ();
     ( $($name:ident,)+ ) => (
-        impl<$($name:Decodable),*> Decodable for ($($name,)*) {
+        impl<$($name:Decodable),+> Decodable for ($($name,)+) {
             #[allow(non_snake_case)]
-            fn decode<D: Decoder>(d: &mut D) -> Result<($($name,)*), D::Error> {
-                let len: usize = count!($($name)*);
+            fn decode<D: Decoder>(d: &mut D) -> Result<($($name,)+), D::Error> {
+                let len: usize = count!($($name)+);
                 d.read_tuple(len, |d| {
                     let mut i = 0;
                     let ret = ($(d.read_tuple_arg({ i+=1; i-1 }, |d| -> Result<$name, D::Error> {
                         Decodable::decode(d)
-                    })?,)*);
+                    })?,)+);
                     Ok(ret)
                 })
             }
         }
-        impl<$($name:Encodable),*> Encodable for ($($name,)*) {
+        impl<$($name:Encodable),+> Encodable for ($($name,)+) {
             #[allow(non_snake_case)]
             fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
-                let ($(ref $name,)*) = *self;
+                let ($(ref $name,)+) = *self;
                 let mut n = 0;
-                $(let $name = $name; n += 1;)*
+                $(let $name = $name; n += 1;)+
                 s.emit_tuple(n, |s| {
                     let mut i = 0;
-                    $(s.emit_tuple_arg({ i+=1; i-1 }, |s| $name.encode(s))?;)*
+                    $(s.emit_tuple_arg({ i+=1; i-1 }, |s| $name.encode(s))?;)+
                     Ok(())
                 })
             }
         }
-        peel! { $($name,)* }
+        peel! { $($name,)+ }
     )
 }
 

src/libsyntax/ext/expand.rs

@@ -98,9 +98,9 @@ pub fn mut_visit_with<F: MutVisitor>(&mut self, vis: &mut F) {
                             }
                         });
                     }
-                    $($(AstFragment::$Kind(ast) => vis.$mut_visit_ast(ast),)*)*
+                    $($(AstFragment::$Kind(ast) => vis.$mut_visit_ast(ast),)?)*
                     $($(AstFragment::$Kind(ast) =>
-                        ast.flat_map_in_place(|ast| vis.$flat_map_ast_elt(ast)),)*)*
+                        ast.flat_map_in_place(|ast| vis.$flat_map_ast_elt(ast)),)?)*
                 }
             }
 
@@ -108,10 +108,10 @@ pub fn visit_with<'a, V: Visitor<'a>>(&'a self, visitor: &mut V) {
                 match *self {
                     AstFragment::OptExpr(Some(ref expr)) => visitor.visit_expr(expr),
                     AstFragment::OptExpr(None) => {}
-                    $($(AstFragment::$Kind(ref ast) => visitor.$visit_ast(ast),)*)*
+                    $($(AstFragment::$Kind(ref ast) => visitor.$visit_ast(ast),)?)*
                     $($(AstFragment::$Kind(ref ast) => for ast_elt in &ast[..] {
                         visitor.$visit_ast_elt(ast_elt);
-                    })*)*
+                    })?)*
                 }
             }
         }
@@ -122,10 +122,10 @@ fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
             }
             $($(fn $mut_visit_ast(&mut self, ast: &mut $AstTy) {
                 visit_clobber(ast, |ast| self.expand_fragment(AstFragment::$Kind(ast)).$make_ast());
-            })*)*
+            })?)*
             $($(fn $flat_map_ast_elt(&mut self, ast_elt: <$AstTy as IntoIterator>::Item) -> $AstTy {
                 self.expand_fragment(AstFragment::$Kind(smallvec![ast_elt])).$make_ast()
-            })*)*
+            })?)*
         }
 
         impl<'a> MacResult for crate::ext::tt::macro_rules::ParserAnyMacro<'a> {

src/libsyntax_ext/deriving/mod.rs

@@ -88,7 +88,7 @@ pub fn register_builtin_derives(resolver: &mut dyn Resolver, edition: Edition) {
                         )
                     }),
                 );
-            )*
+            )+
         }
     }
 }

src/libsyntax_ext/proc_macro_server.rs

@@ -70,7 +70,7 @@ fn from_internal(((tree, is_joint), sess, stack): (TreeAndJoint, &ParseSess, &mu
         macro_rules! tt {
             ($ty:ident { $($field:ident $(: $value:expr)*),+ $(,)? }) => (
                 TokenTree::$ty(self::$ty {
-                    $($field $(: $value)*,)*
+                    $($field $(: $value)*,)+
                     span,
                 })
             );

src/test/ui/issues/issue-22814.rs

@@ -3,7 +3,7 @@ trait Test {}
 
 macro_rules! test {
 ( $($name:ident)+) => (
-    impl<$($name: Test),*> Test for ($($name,)*) {
+    impl<$($name: Test),+> Test for ($($name,)+) {
     }
 )
 }