mbe: Refactor diagnostics for invalid metavar expression syntax
Give a more user-friendly diagnostic about the following:
* Trailing tokens within braces, e.g. `${foo() extra}`
* Missing parentheses, e.g. `${foo}`
* Incorrect number of arguments, with a hint about correct usage.
This commit is contained in:
Trevor Gross
parent
e43d139a82
commit
e7ef31d651
5 changed files with 241 additions and 129 deletions
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@ -133,6 +133,27 @@ expand_module_multiple_candidates =
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expand_must_repeat_once =
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this must repeat at least once
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expand_mve_extra_tokens =
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unexpected trailing tokens
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.label = for this metavariable expression
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.range = the `{$name}` metavariable expression takes between {$min_or_exact_args} and {$max_args} arguments
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.exact = the `{$name}` metavariable expression takes {$min_or_exact_args ->
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[zero] no arguments
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[one] a single argument
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*[other] {$min_or_exact_args} arguments
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}
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.suggestion = try removing {$extra_count ->
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[one] this token
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*[other] these tokens
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}
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expand_mve_missing_paren =
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expected `(`
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.label = for this this metavariable expression
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.unexpected = unexpected token
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.note = metavariable expressions use function-like parentheses syntax
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.suggestion = try adding parentheses
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expand_mve_unrecognized_var =
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variable `{$key}` is not recognized in meta-variable expression
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@ -496,6 +496,40 @@ pub(crate) use metavar_exprs::*;
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mod metavar_exprs {
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use super::*;
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#[derive(Diagnostic, Default)]
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#[diag(expand_mve_extra_tokens)]
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pub(crate) struct MveExtraTokens {
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#[primary_span]
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#[suggestion(code = "", applicability = "machine-applicable")]
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pub span: Span,
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#[label]
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pub ident_span: Span,
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pub extra_count: usize,
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// The rest is only used for specific diagnostics and can be default if neither
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// `note` is `Some`.
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#[note(expand_exact)]
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pub exact_args_note: Option<()>,
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#[note(expand_range)]
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pub range_args_note: Option<()>,
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pub min_or_exact_args: usize,
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pub max_args: usize,
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pub name: String,
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}
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#[derive(Diagnostic)]
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#[note]
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#[diag(expand_mve_missing_paren)]
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pub(crate) struct MveMissingParen {
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#[primary_span]
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#[label]
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pub ident_span: Span,
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#[label(expand_unexpected)]
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pub unexpected_span: Option<Span>,
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#[suggestion(code = "( /* ... */ )", applicability = "has-placeholders")]
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pub insert_span: Option<Span>,
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}
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#[derive(Diagnostic)]
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#[diag(expand_mve_unrecognized_var)]
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pub(crate) struct MveUnrecognizedVar {
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@ -7,6 +7,8 @@ use rustc_macros::{Decodable, Encodable};
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use rustc_session::parse::ParseSess;
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use rustc_span::{Ident, Span, Symbol};
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use crate::errors;
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pub(crate) const RAW_IDENT_ERR: &str = "`${concat(..)}` currently does not support raw identifiers";
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pub(crate) const UNSUPPORTED_CONCAT_ELEM_ERR: &str = "expected identifier or string literal";
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@ -40,11 +42,32 @@ impl MetaVarExpr {
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) -> PResult<'psess, MetaVarExpr> {
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let mut iter = input.iter();
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let ident = parse_ident(&mut iter, psess, outer_span)?;
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let Some(TokenTree::Delimited(.., Delimiter::Parenthesis, args)) = iter.next() else {
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let msg = "meta-variable expression parameter must be wrapped in parentheses";
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return Err(psess.dcx().struct_span_err(ident.span, msg));
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let next = iter.next();
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let Some(TokenTree::Delimited(.., Delimiter::Parenthesis, args)) = next else {
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// No `()`; wrong or no delimiters. Point at a problematic span or a place to
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// add parens if it makes sense.
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let (unexpected_span, insert_span) = match next {
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Some(TokenTree::Delimited(..)) => (None, None),
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Some(tt) => (Some(tt.span()), None),
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None => (None, Some(ident.span.shrink_to_hi())),
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};
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let err =
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errors::MveMissingParen { ident_span: ident.span, unexpected_span, insert_span };
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return Err(psess.dcx().create_err(err));
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};
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check_trailing_token(&mut iter, psess)?;
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// Ensure there are no trailing tokens in the braces, e.g. `${foo() extra}`
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if iter.peek().is_some() {
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let span = iter_span(&iter).expect("checked is_some above");
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let err = errors::MveExtraTokens {
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span,
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ident_span: ident.span,
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extra_count: iter.count(),
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..Default::default()
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};
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return Err(psess.dcx().create_err(err));
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}
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let mut iter = args.iter();
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let rslt = match ident.as_str() {
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"concat" => parse_concat(&mut iter, psess, outer_span, ident.span)?,
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@ -67,7 +90,7 @@ impl MetaVarExpr {
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return Err(err);
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}
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};
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check_trailing_token(&mut iter, psess)?;
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check_trailing_tokens(&mut iter, psess, ident)?;
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Ok(rslt)
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}
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@ -87,20 +110,51 @@ impl MetaVarExpr {
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}
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}
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// Checks if there are any remaining tokens. For example, `${ignore(ident ... a b c ...)}`
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fn check_trailing_token<'psess>(
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/// Checks if there are any remaining tokens (for example, `${ignore($valid, extra)}`) and create
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/// a diag with the correct arg count if so.
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fn check_trailing_tokens<'psess>(
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iter: &mut TokenStreamIter<'_>,
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psess: &'psess ParseSess,
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ident: Ident,
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) -> PResult<'psess, ()> {
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if let Some(tt) = iter.next() {
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let mut diag = psess
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.dcx()
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.struct_span_err(tt.span(), format!("unexpected token: {}", pprust::tt_to_string(tt)));
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diag.span_note(tt.span(), "meta-variable expression must not have trailing tokens");
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Err(diag)
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} else {
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Ok(())
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if iter.peek().is_none() {
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// All tokens consumed, as expected
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return Ok(());
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}
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// `None` for max indicates the arg count must be exact, `Some` indicates a range is accepted.
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let (min_or_exact_args, max_args) = match ident.as_str() {
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"concat" => panic!("concat takes unlimited tokens but didn't eat them all"),
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"ignore" => (1, None),
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// 1 or 2 args
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"count" => (1, Some(2)),
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// 0 or 1 arg
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"index" => (0, Some(1)),
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"len" => (0, Some(1)),
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other => unreachable!("unknown MVEs should be rejected earlier (got `{other}`)"),
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};
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let err = errors::MveExtraTokens {
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span: iter_span(iter).expect("checked is_none above"),
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ident_span: ident.span,
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extra_count: iter.count(),
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exact_args_note: if max_args.is_some() { None } else { Some(()) },
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range_args_note: if max_args.is_some() { Some(()) } else { None },
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min_or_exact_args,
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max_args: max_args.unwrap_or_default(),
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name: ident.to_string(),
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};
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Err(psess.dcx().create_err(err))
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}
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/// Returns a span encompassing all tokens in the iterator if there is at least one item.
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fn iter_span(iter: &TokenStreamIter<'_>) -> Option<Span> {
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let mut iter = iter.clone(); // cloning is cheap
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let first_sp = iter.next()?.span();
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let last_sp = iter.last().map(TokenTree::span).unwrap_or(first_sp);
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let span = first_sp.with_hi(last_sp.hi());
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Some(span)
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}
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/// Indicates what is placed in a `concat` parameter. For example, literals
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@ -30,7 +30,7 @@ macro_rules! metavar_with_literal_suffix {
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macro_rules! mve_without_parens {
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( $( $i:ident ),* ) => { ${ count } };
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//~^ ERROR meta-variable expression parameter must be wrapped in parentheses
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//~^ ERROR expected `(`
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}
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#[rustfmt::skip]
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@ -45,9 +45,14 @@ macro_rules! open_brackets_with_lit {
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//~^ ERROR expected identifier
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}
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macro_rules! mvs_missing_paren {
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( $( $i:ident ),* ) => { ${ count $i ($i) } };
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//~^ ERROR expected `(`
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}
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macro_rules! mve_wrong_delim {
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( $( $i:ident ),* ) => { ${ count{i} } };
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//~^ ERROR meta-variable expression parameter must be wrapped in parentheses
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//~^ ERROR expected `(`
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}
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macro_rules! invalid_metavar {
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@ -64,28 +69,30 @@ macro_rules! open_brackets_with_group {
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macro_rules! extra_garbage_after_metavar {
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( $( $i:ident ),* ) => {
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${count() a b c}
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//~^ ERROR unexpected token: a
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//~^ ERROR unexpected trailing tokens
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${count($i a b c)}
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//~^ ERROR unexpected token: a
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//~^ ERROR unexpected trailing tokens
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${count($i, 1 a b c)}
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//~^ ERROR unexpected token: a
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//~^ ERROR unexpected trailing tokens
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${count($i) a b c}
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//~^ ERROR unexpected token: a
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//~^ ERROR unexpected trailing tokens
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${ignore($i) a b c}
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//~^ ERROR unexpected token: a
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//~^ ERROR unexpected trailing tokens
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${ignore($i a b c)}
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//~^ ERROR unexpected token: a
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//~^ ERROR unexpected trailing tokens
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${index() a b c}
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//~^ ERROR unexpected token: a
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//~^ ERROR unexpected trailing tokens
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${index(1 a b c)}
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//~^ ERROR unexpected token: a
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//~^ ERROR unexpected trailing tokens
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${index() a b c}
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//~^ ERROR unexpected token: a
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//~^ ERROR unexpected trailing tokens
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${index(1 a b c)}
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//~^ ERROR unexpected token: a
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//~^ ERROR unexpected trailing tokens
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${index(1, a b c)}
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//~^ ERROR unexpected trailing tokens
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};
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}
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@ -40,164 +40,160 @@ error: only unsuffixes integer literals are supported in meta-variable expressio
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LL | ( $( $i:ident ),* ) => { ${ index(1u32) } };
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| ^^^^^
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error: meta-variable expression parameter must be wrapped in parentheses
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error: expected `(`
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--> $DIR/syntax-errors.rs:32:33
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LL | ( $( $i:ident ),* ) => { ${ count } };
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| ^^^^^
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| ^^^^^- help: try adding parentheses: `( /* ... */ )`
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| |
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| for this this metavariable expression
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= note: metavariable expressions use function-like parentheses syntax
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error: meta-variable expression parameter must be wrapped in parentheses
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error: expected `(`
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--> $DIR/syntax-errors.rs:49:33
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LL | ( $( $i:ident ),* ) => { ${ count $i ($i) } };
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| ^^^^^ - unexpected token
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| |
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| for this this metavariable expression
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= note: metavariable expressions use function-like parentheses syntax
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error: expected `(`
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--> $DIR/syntax-errors.rs:54:33
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LL | ( $( $i:ident ),* ) => { ${ count{i} } };
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| ^^^^^
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| ^^^^^ for this this metavariable expression
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= note: metavariable expressions use function-like parentheses syntax
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error: expected identifier, found `123`
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--> $DIR/syntax-errors.rs:54:23
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--> $DIR/syntax-errors.rs:59:23
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LL | () => { ${ignore($123)} }
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| ^^^ help: try removing `123`
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error: unexpected token: a
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--> $DIR/syntax-errors.rs:66:19
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error: unexpected trailing tokens
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--> $DIR/syntax-errors.rs:71:19
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LL | ${count() a b c}
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| ^
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note: meta-variable expression must not have trailing tokens
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--> $DIR/syntax-errors.rs:66:19
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LL | ${count() a b c}
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| ^
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| ----- ^^^^^ help: try removing these tokens
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| |
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| for this metavariable expression
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error: unexpected token: a
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--> $DIR/syntax-errors.rs:68:20
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error: unexpected trailing tokens
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--> $DIR/syntax-errors.rs:73:20
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LL | ${count($i a b c)}
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| ^
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| ----- ^^^^^ help: try removing these tokens
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| |
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| for this metavariable expression
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note: meta-variable expression must not have trailing tokens
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--> $DIR/syntax-errors.rs:68:20
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LL | ${count($i a b c)}
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| ^
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= note: the `count` metavariable expression takes between 1 and 2 arguments
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error: unexpected token: a
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--> $DIR/syntax-errors.rs:70:23
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error: unexpected trailing tokens
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--> $DIR/syntax-errors.rs:75:23
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LL | ${count($i, 1 a b c)}
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| ^
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| ----- ^^^^^ help: try removing these tokens
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| |
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| for this metavariable expression
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note: meta-variable expression must not have trailing tokens
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--> $DIR/syntax-errors.rs:70:23
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LL | ${count($i, 1 a b c)}
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| ^
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= note: the `count` metavariable expression takes between 1 and 2 arguments
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error: unexpected token: a
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--> $DIR/syntax-errors.rs:72:21
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LL | ${count($i) a b c}
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| ^
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|
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note: meta-variable expression must not have trailing tokens
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--> $DIR/syntax-errors.rs:72:21
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LL | ${count($i) a b c}
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| ^
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error: unexpected token: a
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--> $DIR/syntax-errors.rs:75:22
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LL | ${ignore($i) a b c}
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| ^
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|
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note: meta-variable expression must not have trailing tokens
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--> $DIR/syntax-errors.rs:75:22
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|
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LL | ${ignore($i) a b c}
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| ^
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error: unexpected token: a
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error: unexpected trailing tokens
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--> $DIR/syntax-errors.rs:77:21
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|
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LL | ${ignore($i a b c)}
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| ^
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LL | ${count($i) a b c}
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| ----- ^^^^^ help: try removing these tokens
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| |
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| for this metavariable expression
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error: unexpected trailing tokens
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--> $DIR/syntax-errors.rs:80:22
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|
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note: meta-variable expression must not have trailing tokens
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--> $DIR/syntax-errors.rs:77:21
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LL | ${ignore($i) a b c}
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| ------ ^^^^^ help: try removing these tokens
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| |
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| for this metavariable expression
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error: unexpected trailing tokens
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--> $DIR/syntax-errors.rs:82:21
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|
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LL | ${ignore($i a b c)}
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| ^
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| ------ ^^^^^ help: try removing these tokens
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| |
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| for this metavariable expression
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|
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= note: the `ignore` metavariable expression takes a single argument
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error: unexpected token: a
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--> $DIR/syntax-errors.rs:80:19
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|
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LL | ${index() a b c}
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| ^
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|
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note: meta-variable expression must not have trailing tokens
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--> $DIR/syntax-errors.rs:80:19
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|
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LL | ${index() a b c}
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| ^
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error: unexpected token: a
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--> $DIR/syntax-errors.rs:82:19
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|
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LL | ${index(1 a b c)}
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| ^
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|
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note: meta-variable expression must not have trailing tokens
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--> $DIR/syntax-errors.rs:82:19
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|
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LL | ${index(1 a b c)}
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| ^
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error: unexpected token: a
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error: unexpected trailing tokens
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--> $DIR/syntax-errors.rs:85:19
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|
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LL | ${index() a b c}
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| ^
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| ----- ^^^^^ help: try removing these tokens
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| |
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| for this metavariable expression
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error: unexpected trailing tokens
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--> $DIR/syntax-errors.rs:87:19
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|
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note: meta-variable expression must not have trailing tokens
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--> $DIR/syntax-errors.rs:85:19
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LL | ${index(1 a b c)}
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| ----- ^^^^^ help: try removing these tokens
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| |
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| for this metavariable expression
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|
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= note: the `index` metavariable expression takes between 0 and 1 arguments
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error: unexpected trailing tokens
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--> $DIR/syntax-errors.rs:90:19
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|
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LL | ${index() a b c}
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| ^
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| ----- ^^^^^ help: try removing these tokens
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| |
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| for this metavariable expression
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error: unexpected token: a
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--> $DIR/syntax-errors.rs:87:19
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error: unexpected trailing tokens
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--> $DIR/syntax-errors.rs:92:19
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|
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LL | ${index(1 a b c)}
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| ^
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| ----- ^^^^^ help: try removing these tokens
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| |
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| for this metavariable expression
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|
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note: meta-variable expression must not have trailing tokens
|
||||
--> $DIR/syntax-errors.rs:87:19
|
||||
= note: the `index` metavariable expression takes between 0 and 1 arguments
|
||||
|
||||
error: unexpected trailing tokens
|
||||
--> $DIR/syntax-errors.rs:94:18
|
||||
|
|
||||
LL | ${index(1 a b c)}
|
||||
| ^
|
||||
LL | ${index(1, a b c)}
|
||||
| ----- ^^^^^^^ help: try removing these tokens
|
||||
| |
|
||||
| for this metavariable expression
|
||||
|
|
||||
= note: the `index` metavariable expression takes between 0 and 1 arguments
|
||||
|
||||
error: meta-variable expression depth must be a literal
|
||||
--> $DIR/syntax-errors.rs:94:33
|
||||
--> $DIR/syntax-errors.rs:101:33
|
||||
|
|
||||
LL | ( $( $i:ident ),* ) => { ${ index(IDX) } };
|
||||
| ^^^^^
|
||||
|
||||
error: meta-variables within meta-variable expressions must be referenced using a dollar sign
|
||||
--> $DIR/syntax-errors.rs:100:11
|
||||
--> $DIR/syntax-errors.rs:107:11
|
||||
|
|
||||
LL | ${count(foo)}
|
||||
| ^^^^^
|
||||
|
||||
error: meta-variables within meta-variable expressions must be referenced using a dollar sign
|
||||
--> $DIR/syntax-errors.rs:107:11
|
||||
--> $DIR/syntax-errors.rs:114:11
|
||||
|
|
||||
LL | ${ignore(bar)}
|
||||
| ^^^^^^
|
||||
|
||||
error: unrecognized meta-variable expression
|
||||
--> $DIR/syntax-errors.rs:113:33
|
||||
--> $DIR/syntax-errors.rs:120:33
|
||||
|
|
||||
LL | ( $( $i:ident ),* ) => { ${ aaaaaaaaaaaaaa(i) } };
|
||||
| ^^^^^^^^^^^^^^ help: supported expressions are count, ignore, index and len
|
||||
|
|
@ -215,10 +211,10 @@ LL | () => { ${ "hi" } };
|
|||
| ^^^^ help: try removing `"hi"`
|
||||
|
||||
error: expected identifier or string literal
|
||||
--> $DIR/syntax-errors.rs:60:33
|
||||
--> $DIR/syntax-errors.rs:65:33
|
||||
|
|
||||
LL | ( $( $i:ident ),* ) => { ${ {} } };
|
||||
| ^^
|
||||
|
||||
error: aborting due to 25 previous errors
|
||||
error: aborting due to 27 previous errors
|
||||
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue