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925f7fad57
`tokenstream::Spacing` appears on all `TokenTree::Token` instances, both punct and non-punct. Its current usage: - `Joint` means "can join with the next token *and* that token is a punct". - `Alone` means "cannot join with the next token *or* can join with the next token but that token is not a punct". The fact that `Alone` is used for two different cases is awkward. This commit augments `tokenstream::Spacing` with a new variant `JointHidden`, resulting in: - `Joint` means "can join with the next token *and* that token is a punct". - `JointHidden` means "can join with the next token *and* that token is a not a punct". - `Alone` means "cannot join with the next token". This *drastically* improves the output of `print_tts`. For example, this: ``` stringify!(let a: Vec<u32> = vec![];) ``` currently produces this string: ``` let a : Vec < u32 > = vec! [] ; ``` With this PR, it now produces this string: ``` let a: Vec<u32> = vec![] ; ``` (The space after the `]` is because `TokenTree::Delimited` currently doesn't have spacing information. The subsequent commit fixes this.) The new `print_tts` doesn't replicate original code perfectly. E.g. multiple space characters will be condensed into a single space character. But it's much improved. `print_tts` still produces the old, uglier output for code produced by proc macros. Because we have to translate the generated code from `proc_macro::Spacing` to the more expressive `token::Spacing`, which results in too much `proc_macro::Along` usage and no `proc_macro::JointHidden` usage. So `space_between` still exists and is used by `print_tts` in conjunction with the `Spacing` field. This change will also help with the removal of `Token::Interpolated`. Currently interpolated tokens are pretty-printed nicely via AST pretty printing. `Token::Interpolated` removal will mean they get printed with `print_tts`. Without this change, that would result in much uglier output for code produced by decl macro expansions. With this change, AST pretty printing and `print_tts` produce similar results. The commit also tweaks the comments on `proc_macro::Spacing`. In particular, it refers to "compound tokens" rather than "multi-char operators" because lifetimes aren't operators.
194 lines
6.4 KiB
Text
194 lines
6.4 KiB
Text
PRINT-ATTR INPUT (DISPLAY): #[derive(Print)] struct AttributeDerive { #[cfg(FALSE)] field: u8, }
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PRINT-ATTR DEEP-RE-COLLECTED (DISPLAY): #[derive(Print)] struct AttributeDerive { #[cfg(FALSE)] field : u8, }
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PRINT-ATTR INPUT (DEBUG): TokenStream [
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Punct {
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ch: '#',
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spacing: Alone,
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span: $DIR/attribute-after-derive.rs:15:1: 15:2 (#0),
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},
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Group {
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delimiter: Bracket,
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stream: TokenStream [
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Ident {
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ident: "derive",
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span: $DIR/attribute-after-derive.rs:15:3: 15:9 (#0),
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},
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Group {
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delimiter: Parenthesis,
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stream: TokenStream [
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Ident {
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ident: "Print",
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span: $DIR/attribute-after-derive.rs:15:10: 15:15 (#0),
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},
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],
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span: $DIR/attribute-after-derive.rs:15:9: 15:16 (#0),
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},
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],
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span: $DIR/attribute-after-derive.rs:15:2: 15:17 (#0),
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},
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Ident {
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ident: "struct",
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span: $DIR/attribute-after-derive.rs:16:1: 16:7 (#0),
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},
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Ident {
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ident: "AttributeDerive",
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span: $DIR/attribute-after-derive.rs:16:8: 16:23 (#0),
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},
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Group {
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delimiter: Brace,
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stream: TokenStream [
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Punct {
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ch: '#',
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spacing: Alone,
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span: $DIR/attribute-after-derive.rs:17:5: 17:6 (#0),
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},
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Group {
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delimiter: Bracket,
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stream: TokenStream [
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Ident {
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ident: "cfg",
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span: $DIR/attribute-after-derive.rs:17:7: 17:10 (#0),
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},
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Group {
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delimiter: Parenthesis,
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stream: TokenStream [
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Ident {
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ident: "FALSE",
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span: $DIR/attribute-after-derive.rs:17:11: 17:16 (#0),
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},
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],
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span: $DIR/attribute-after-derive.rs:17:10: 17:17 (#0),
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},
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],
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span: $DIR/attribute-after-derive.rs:17:6: 17:18 (#0),
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},
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Ident {
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ident: "field",
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span: $DIR/attribute-after-derive.rs:18:5: 18:10 (#0),
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},
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Punct {
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ch: ':',
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spacing: Alone,
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span: $DIR/attribute-after-derive.rs:18:10: 18:11 (#0),
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},
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Ident {
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ident: "u8",
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span: $DIR/attribute-after-derive.rs:18:12: 18:14 (#0),
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},
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Punct {
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ch: ',',
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spacing: Alone,
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span: $DIR/attribute-after-derive.rs:18:14: 18:15 (#0),
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},
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],
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span: $DIR/attribute-after-derive.rs:16:24: 19:2 (#0),
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},
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]
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PRINT-DERIVE INPUT (DISPLAY): struct AttributeDerive {}
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PRINT-DERIVE INPUT (DEBUG): TokenStream [
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Ident {
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ident: "struct",
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span: $DIR/attribute-after-derive.rs:16:1: 16:7 (#0),
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},
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Ident {
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ident: "AttributeDerive",
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span: $DIR/attribute-after-derive.rs:16:8: 16:23 (#0),
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},
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Group {
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delimiter: Brace,
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stream: TokenStream [],
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span: $DIR/attribute-after-derive.rs:16:24: 19:2 (#0),
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},
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]
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PRINT-DERIVE INPUT (DISPLAY): #[print_attr] struct DeriveAttribute {}
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PRINT-DERIVE INPUT (DEBUG): TokenStream [
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Punct {
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ch: '#',
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spacing: Alone,
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span: $DIR/attribute-after-derive.rs:22:1: 22:2 (#0),
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},
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Group {
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delimiter: Bracket,
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stream: TokenStream [
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Ident {
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ident: "print_attr",
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span: $DIR/attribute-after-derive.rs:22:3: 22:13 (#0),
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},
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],
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span: $DIR/attribute-after-derive.rs:22:2: 22:14 (#0),
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},
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Ident {
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ident: "struct",
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span: $DIR/attribute-after-derive.rs:23:1: 23:7 (#0),
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},
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Ident {
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ident: "DeriveAttribute",
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span: $DIR/attribute-after-derive.rs:23:8: 23:23 (#0),
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},
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Group {
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delimiter: Brace,
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stream: TokenStream [],
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span: $DIR/attribute-after-derive.rs:23:24: 26:2 (#0),
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},
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]
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PRINT-ATTR INPUT (DISPLAY): struct DeriveAttribute { #[cfg(FALSE)] field: u8, }
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PRINT-ATTR DEEP-RE-COLLECTED (DISPLAY): struct DeriveAttribute { #[cfg(FALSE)] field : u8, }
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PRINT-ATTR INPUT (DEBUG): TokenStream [
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Ident {
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ident: "struct",
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span: $DIR/attribute-after-derive.rs:23:1: 23:7 (#0),
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},
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Ident {
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ident: "DeriveAttribute",
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span: $DIR/attribute-after-derive.rs:23:8: 23:23 (#0),
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},
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Group {
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delimiter: Brace,
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stream: TokenStream [
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Punct {
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ch: '#',
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spacing: Alone,
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span: $DIR/attribute-after-derive.rs:24:5: 24:6 (#0),
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},
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Group {
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delimiter: Bracket,
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stream: TokenStream [
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Ident {
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ident: "cfg",
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span: $DIR/attribute-after-derive.rs:24:7: 24:10 (#0),
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},
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Group {
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delimiter: Parenthesis,
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stream: TokenStream [
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Ident {
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ident: "FALSE",
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span: $DIR/attribute-after-derive.rs:24:11: 24:16 (#0),
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},
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],
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span: $DIR/attribute-after-derive.rs:24:10: 24:17 (#0),
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},
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],
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span: $DIR/attribute-after-derive.rs:24:6: 24:18 (#0),
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},
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Ident {
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ident: "field",
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span: $DIR/attribute-after-derive.rs:25:5: 25:10 (#0),
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},
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Punct {
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ch: ':',
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spacing: Alone,
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span: $DIR/attribute-after-derive.rs:25:10: 25:11 (#0),
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},
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Ident {
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ident: "u8",
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span: $DIR/attribute-after-derive.rs:25:12: 25:14 (#0),
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},
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Punct {
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ch: ',',
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spacing: Alone,
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span: $DIR/attribute-after-derive.rs:25:14: 25:15 (#0),
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},
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],
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span: $DIR/attribute-after-derive.rs:23:24: 26:2 (#0),
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},
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]
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