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use rustc_ast as ast;
use rustc_ast::{ptr::P, tokenstream::TokenStream};
use rustc_errors::Applicability;
use rustc_expand::base::{self, DummyResult};
fn invalid_type_err(cx: &mut base::ExtCtxt<'_>, expr: &P<rustc_ast::Expr>, is_nested: bool) {
let ast::ExprKind::Lit(lit) = &expr.kind else {
unreachable!();
};
match lit.kind {
ast::LitKind::Char(_) => {
let mut err = cx.struct_span_err(expr.span, "cannot concatenate character literals");
if let Ok(snippet) = cx.sess.source_map().span_to_snippet(expr.span) {
err.span_suggestion(
expr.span,
"try using a byte character",
format!("b{}", snippet),
Applicability::MachineApplicable,
)
.emit();
}
}
ast::LitKind::Str(_, _) => {
let mut err = cx.struct_span_err(expr.span, "cannot concatenate string literals");
if !is_nested {
if let Ok(snippet) = cx.sess.source_map().span_to_snippet(expr.span) {
err.span_suggestion(
expr.span,
"try using a byte string",
format!("b{}", snippet),
Applicability::MachineApplicable,
);
}
}
err.emit();
}
ast::LitKind::Float(_, _) => {
cx.span_err(expr.span, "cannot concatenate float literals");
}
ast::LitKind::Bool(_) => {
cx.span_err(expr.span, "cannot concatenate boolean literals");
}
ast::LitKind::Err => {}
ast::LitKind::Int(_, _) if !is_nested => {
let mut err = cx.struct_span_err(expr.span, "cannot concatenate numeric literals");
if let Ok(snippet) = cx.sess.source_map().span_to_snippet(expr.span) {
err.span_suggestion(
expr.span,
"try wrapping the number in an array",
format!("[{}]", snippet),
Applicability::MachineApplicable,
);
}
err.emit();
}
ast::LitKind::Int(
val,
ast::LitIntType::Unsuffixed | ast::LitIntType::Unsigned(ast::UintTy::U8),
) => {
assert!(val > u8::MAX.into()); cx.span_err(expr.span, "numeric literal is out of bounds");
}
ast::LitKind::Int(_, _) => {
cx.span_err(expr.span, "numeric literal is not a `u8`");
}
_ => unreachable!(),
}
}
fn handle_array_element(
cx: &mut base::ExtCtxt<'_>,
has_errors: &mut bool,
missing_literals: &mut Vec<rustc_span::Span>,
expr: &P<rustc_ast::Expr>,
) -> Option<u8> {
match expr.kind {
ast::ExprKind::Array(_) | ast::ExprKind::Repeat(_, _) => {
if !*has_errors {
cx.span_err(expr.span, "cannot concatenate doubly nested array");
}
*has_errors = true;
None
}
ast::ExprKind::Lit(ref lit) => match lit.kind {
ast::LitKind::Int(
val,
ast::LitIntType::Unsuffixed | ast::LitIntType::Unsigned(ast::UintTy::U8),
) if val <= u8::MAX.into() => Some(val as u8),
ast::LitKind::Byte(val) => Some(val),
ast::LitKind::ByteStr(_) => {
if !*has_errors {
cx.struct_span_err(expr.span, "cannot concatenate doubly nested array")
.note("byte strings are treated as arrays of bytes")
.help("try flattening the array")
.emit();
}
*has_errors = true;
None
}
_ => {
if !*has_errors {
invalid_type_err(cx, expr, true);
}
*has_errors = true;
None
}
},
_ => {
missing_literals.push(expr.span);
None
}
}
}
pub fn expand_concat_bytes(
cx: &mut base::ExtCtxt<'_>,
sp: rustc_span::Span,
tts: TokenStream,
) -> Box<dyn base::MacResult + 'static> {
let Some(es) = base::get_exprs_from_tts(cx, sp, tts) else {
return DummyResult::any(sp);
};
let mut accumulator = Vec::new();
let mut missing_literals = vec![];
let mut has_errors = false;
for e in es {
match e.kind {
ast::ExprKind::Array(ref exprs) => {
for expr in exprs {
if let Some(elem) =
handle_array_element(cx, &mut has_errors, &mut missing_literals, expr)
{
accumulator.push(elem);
}
}
}
ast::ExprKind::Repeat(ref expr, ref count) => {
if let ast::ExprKind::Lit(ast::Lit {
kind: ast::LitKind::Int(count_val, _), ..
}) = count.value.kind
{
if let Some(elem) =
handle_array_element(cx, &mut has_errors, &mut missing_literals, expr)
{
for _ in 0..count_val {
accumulator.push(elem);
}
}
} else {
cx.span_err(count.value.span, "repeat count is not a positive number");
}
}
ast::ExprKind::Lit(ref lit) => match lit.kind {
ast::LitKind::Byte(val) => {
accumulator.push(val);
}
ast::LitKind::ByteStr(ref bytes) => {
accumulator.extend_from_slice(&bytes);
}
_ => {
if !has_errors {
invalid_type_err(cx, &e, false);
}
has_errors = true;
}
},
ast::ExprKind::Err => {
has_errors = true;
}
_ => {
missing_literals.push(e.span);
}
}
}
if !missing_literals.is_empty() {
let mut err = cx.struct_span_err(missing_literals.clone(), "expected a byte literal");
err.note("only byte literals (like `b\"foo\"`, `b's'`, and `[3, 4, 5]`) can be passed to `concat_bytes!()`");
err.emit();
return base::MacEager::expr(DummyResult::raw_expr(sp, true));
} else if has_errors {
return base::MacEager::expr(DummyResult::raw_expr(sp, true));
}
let sp = cx.with_def_site_ctxt(sp);
base::MacEager::expr(cx.expr_byte_str(sp, accumulator))
}
