| @@ -2643,14 +2643,41 @@ impl ToString for i8 { |
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2643 |
} |
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} |
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-#[doc(hidden)] |
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-#[cfg(not(no_global_oom_handling))] |
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-#[stable(feature = "str_to_string_specialization", since = "1.9.0")] |
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-impl ToString for str { |
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-#[inline] |
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-fn to_string(&self) -> String { |
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-String::from(self) |
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-} |
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+// Generic/generated code can sometimes have multiple, nested references |
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+// for strings, including `&&&str`s that would never be written |
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+// by hand. This macro generates twelve layers of nested `&`-impl |
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+// for primitive strings. |
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+macro_rules! to_string_str { |
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+{type ; x (((x:ident)*} => { |
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+&to_string_str! { type ; (((x)* } |
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+}; |
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+{type ;} => { str }; |
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+{impl ; x (((x:ident)*} => { |
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+ to_string_str! { (((x)* } |
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+}; |
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+{impl ;} => { }; |
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+{$self:expr ; x (((x:ident)*} => { |
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+*(to_string_str! { self;self ; self;($x)* }) |
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+}; |
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+{$self:expr ;} => { $self }; |
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+{$($x:ident)*} => { |
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+ #[doc(hidden)] |
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+ #[cfg(not(no_global_oom_handling))] |
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+ #[stable(feature = "str_to_string_specialization", since = "1.9.0")] |
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+impl ToString for to_string_str!(type ; (((x)*) { |
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+ #[inline] |
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+fn to_string(&self) -> String { |
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+String::from(to_string_str!(self ; (((x)*)) |
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+} |
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+} |
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+ to_string_str! { impl ; (((x)* } |
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+}; |
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+} |
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+ |
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+to_string_str! { |
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+ x x x x |
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+ x x x x |
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+ x x x x |
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} |
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#[doc(hidden)] |