return first;
}
TokenTree::Sequence(sp, ref seq_rep) => {
- match self.first.get(&sp.entire()) {
- Some(&Some(ref subfirst)) => {
- // If the sequence contents can be empty, then the first
- // token could be the separator token itself.
-
- if let (Some(sep), true) = (&seq_rep.separator, subfirst.maybe_empty) {
- first.add_one_maybe(TokenTree::Token(sep.clone()));
- }
-
- assert!(first.maybe_empty);
- first.add_all(subfirst);
- if subfirst.maybe_empty
- || seq_rep.kleene.op == quoted::KleeneOp::ZeroOrMore
- || seq_rep.kleene.op == quoted::KleeneOp::ZeroOrOne
- {
- // continue scanning for more first
- // tokens, but also make sure we
- // restore empty-tracking state
- first.maybe_empty = true;
- continue;
- } else {
- return first;
- }
- }
-
+ let subfirst_owned;
+ let subfirst = match self.first.get(&sp.entire()) {
+ Some(&Some(ref subfirst)) => subfirst,
Some(&None) => {
- panic!("assume all sequences have (unique) spans for now");
+ subfirst_owned = self.first(&seq_rep.tts[..]);
+ &subfirst_owned
}
-
None => {
panic!("We missed a sequence during FirstSets construction");
}
+ };
+
+ // If the sequence contents can be empty, then the first
+ // token could be the separator token itself.
+ if let (Some(sep), true) = (&seq_rep.separator, subfirst.maybe_empty) {
+ first.add_one_maybe(TokenTree::Token(sep.clone()));
+ }
+
+ assert!(first.maybe_empty);
+ first.add_all(subfirst);
+ if subfirst.maybe_empty
+ || seq_rep.kleene.op == quoted::KleeneOp::ZeroOrMore
+ || seq_rep.kleene.op == quoted::KleeneOp::ZeroOrOne
+ {
+ // Continue scanning for more first
+ // tokens, but also make sure we
+ // restore empty-tracking state.
+ first.maybe_empty = true;
+ continue;
+ } else {
+ return first;
}
}
}
--- /dev/null
+// force-host
+// no-prefer-dynamic
+
+#![crate_type = "proc-macro"]
+#![feature(proc_macro_span, proc_macro_hygiene, proc_macro_quote)]
+
+extern crate proc_macro;
+
+use proc_macro::{quote, Span, TokenStream};
+
+fn assert_same_span(a: Span, b: Span) {
+ assert_eq!(a.start(), b.start());
+ assert_eq!(a.end(), b.end());
+}
+
+// This macro generates a macro with the same macro definition as `manual_foo` in
+// `same-sequence-span.rs` but with the same span for all sequences.
+#[proc_macro]
+pub fn make_foo(_: TokenStream) -> TokenStream {
+ let result = quote! {
+ macro_rules! generated_foo {
+ (1 $$x:expr $$($$y:tt,)* $$(= $$z:tt)*) => {};
+ }
+ };
+
+ // Check that all spans are equal.
+ let mut span = None;
+ for tt in result.clone() {
+ match span {
+ None => span = Some(tt.span()),
+ Some(span) => assert_same_span(tt.span(), span),
+ }
+ }
+
+ result
+}
--- /dev/null
+// aux-build:proc_macro_sequence.rs
+
+// Regression test for issue #62831: Check that multiple sequences with the same span in the
+// left-hand side of a macro definition behave as if they had unique spans, and in particular that
+// they don't crash the compiler.
+
+#![feature(proc_macro_hygiene)]
+#![allow(unused_macros)]
+
+extern crate proc_macro_sequence;
+
+// When ignoring spans, this macro has the same macro definition as `generated_foo` in
+// `proc_macro_sequence.rs`.
+macro_rules! manual_foo {
+ (1 $x:expr $($y:tt,)* //~ERROR `$x:expr` may be followed by `$y:tt`
+ $(= $z:tt)* //~ERROR `$x:expr` may be followed by `=`
+ ) => {};
+}
+
+proc_macro_sequence::make_foo!(); //~ERROR `$x:expr` may be followed by `$y:tt`
+ //~^ERROR `$x:expr` may be followed by `=`
+
+fn main() {}
--- /dev/null
+error: `$x:expr` may be followed by `$y:tt`, which is not allowed for `expr` fragments
+ --> $DIR/same-sequence-span.rs:15:18
+ |
+LL | (1 $x:expr $($y:tt,)*
+ | ^^^^^ not allowed after `expr` fragments
+ |
+ = note: allowed there are: `=>`, `,` or `;`
+
+error: `$x:expr` may be followed by `=`, which is not allowed for `expr` fragments
+ --> $DIR/same-sequence-span.rs:16:18
+ |
+LL | $(= $z:tt)*
+ | ^ not allowed after `expr` fragments
+ |
+ = note: allowed there are: `=>`, `,` or `;`
+
+error: `$x:expr` may be followed by `$y:tt`, which is not allowed for `expr` fragments
+ --> $DIR/same-sequence-span.rs:20:1
+ |
+LL | proc_macro_sequence::make_foo!();
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not allowed after `expr` fragments
+ |
+ = note: allowed there are: `=>`, `,` or `;`
+
+error: `$x:expr` may be followed by `=`, which is not allowed for `expr` fragments
+ --> $DIR/same-sequence-span.rs:20:1
+ |
+LL | proc_macro_sequence::make_foo!();
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not allowed after `expr` fragments
+ |
+ = note: allowed there are: `=>`, `,` or `;`
+
+error: aborting due to 4 previous errors
+