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Rollup merge of #106844 - Ezrashaw:concat-negative-int-lit, r=dtolnay

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allow negative numeric literals in `concat!`

Fixes #106837

While *technically* negative numeric literals are implemented as unary operations, users can reasonably expect that negative literals are treated the same as positive literals.
This commit is contained in:
Matthias Krüger 2023-03-11 15:43:12 +01:00 • committed by GitHub
commit d47d4ad4b2
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5 changed files with 45 additions and 4 deletions
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15
compiler/rustc_builtin_macros/src/concat.rs
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@ -42,6 +42,18 @@ pub fn expand_concat(
has_errors = true;
}
},
// We also want to allow negative numeric literals.
ast::ExprKind::Unary(ast::UnOp::Neg, ref expr) if let ast::ExprKind::Lit(token_lit) = expr.kind => {
match ast::LitKind::from_token_lit(token_lit) {
Ok(ast::LitKind::Int(i, _)) => accumulator.push_str(&format!("-{i}")),
Ok(ast::LitKind::Float(f, _)) => accumulator.push_str(&format!("-{f}")),
Err(err) => {
report_lit_error(&cx.sess.parse_sess, err, token_lit, e.span);
has_errors = true;
}
_ => missing_literal.push(e.span),
}
}
ast::ExprKind::IncludedBytes(..) => {
cx.span_err(e.span, "cannot concatenate a byte string literal")
}
@ -53,9 +65,10 @@ pub fn expand_concat(
}
}
}
if !missing_literal.is_empty() {
let mut err = cx.struct_span_err(missing_literal, "expected a literal");
err.note("only literals (like `\"foo\"`, `42` and `3.14`) can be passed to `concat!()`");
err.note("only literals (like `\"foo\"`, `-42` and `3.14`) can be passed to `concat!()`");
err.emit();
return DummyResult::any(sp);
} else if has_errors {