A simple Vala program that misses a semi-colon:

void main () {
    string a = ""
}

This would have previously produced the error:
test.vala:3.1-3.1: error: syntax error, expected `;'

Instead latest Vala advises:
test.vala:3.1-3.1: error: syntax error, expected %s

Clearly "expected %s" is inappropriate and unhelpful.

A couple more examples:

1. The following:

void main () {
    if (true {}
}

with latest Vala gives:
test.vala:2.11-2.11: error: syntax error, expected %s

while previous versions reported:
test.vala:2.11-2.11: error: syntax error, expected `)'

2. The following Genie code:

init
    pass
class
    pass

with latest Vala reports:
test.gs:4.2-4.5: error: syntax error, expected declaration  but got %s with previous %s

while previous versions reported:
test.gs:4.2-4.5: error: syntax error, expected declaration  but got `pass' with previous `tab indent'

---


For the Genie example this error message is generated by the parse_declaration () method in the parser with the line:
throw new ParseError.SYNTAX (get_error ("expected declaration  but got %s with previous %s"), cur.to_string (), pre.to_string());
This includes the double space between "declaration" and "but".

For the Vala examples it is probably the expect () method of the Vala parser and the line:
throw new ParseError.SYNTAX (get_error ("expected %s"), type.to_string ());