Misleading location reported for "no viable alternative"

[bannmann]

Example (invalid) AG:

import java.util.List;
import java.util.function.UnaryOperator;

$ADJUSTMENTS = adjusting<F>(List<F> list, UnaryOperator<F> adjuster);

// something else

// more code

Silverchain rejects this with the following error:

Could not generate API: line 9:0 no viable alternative at input '$ADJUSTMENTS=adjusting<F>(List<F>list,UnaryOperator<F>adjuster);// something else// more code'

The location reported is misleading: it points to the end of the file, but should have been something like 4:25 (the <F>) or at least 4:16 (the adjusting<F>).

Especially for large AG files, it takes a while to figure out that it really rejects something at the start of the expression in the error message.