44 lines
1017 B
Rust
44 lines
1017 B
Rust
#![feature(macro_metavar_expr)]
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macro_rules! a {
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( $( { $( [ $( ( $( $foo:ident )* ) )* ] )* } )* ) => {
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(
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${count($foo, 0)},
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${count($foo, 10)},
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//~^ ERROR depth parameter of meta-variable expression `count` must be less than 4
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)
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};
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}
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macro_rules! b {
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( $( { $( [ $( $foo:ident )* ] )* } )* ) => {
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(
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$( $( $(
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${ignore($foo)}
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${index(0)},
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${index(10)},
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//~^ ERROR depth parameter of meta-variable expression `index` must be less than 3
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)* )* )*
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)
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};
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}
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macro_rules! c {
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( $( { $( $foo:ident )* } )* ) => {
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(
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$( $(
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${ignore($foo)}
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${len(0)}
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${len(10)}
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//~^ ERROR depth parameter of meta-variable expression `len` must be less than 2
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)* )*
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)
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};
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}
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fn main() {
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a!( { [ (a) ] [ (b c) ] } );
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b!( { [ a b ] } );
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c!({ a });
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}
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