`continue` expressions in loop conditions

Location

https://doc.rust-lang.org/reference/expressions/loop-expr.html#continue-expressions

Summary

The reference unambiguously states that "A continue expression is only permitted in the body of a loop.", but this is demonstrably not true for continue 'label expressions.

The following compiles and runs an infinite loop. A warning mentions the body being unreachable, but otherwise the behavior is as one would expect:

'a: while continue 'a {}

Meanwhile, the following does not compile:

while { continue; true } {}

In the second example, an error is generated:

error[E0590]: break or continue with no label in the condition of a while loop

Furthermore, rustc --explain E0590 demonstrates label usage with a break expression:

'foo: while break 'foo {}

Unless I have misunderstood something, there seems to be conflicting information between the reference and the actual behavior of the compiler.

Edit: grammar.

Start with the Reference's loop-expressions section at the linked continue-expressions entry, then compare its rule with the labeled and unlabeled examples in the issue. Check rustc --explain E0590 and the reported compiler behavior; done means the intended rule is decided and the Reference and compiler behavior no longer conflict.