QA output created by 431
=== This should work ===

my.string
    value "hullo world!"

my.aggr
    value "hullo world!" [68756c6c6f20776f726c6421]

my.string
    value "hullo world!"

my.aggr
    value "hullo world!" [68756c6c6f20776f726c6421]

=== These should NOT work ===
Semantic error: derived metric my.bad_1: sample.string.hullo - sample.aggregate.hullo: Non-arithmetic type for left operand
Semantic error: derived metric my.bad_2: 1 + sample.string.hullo: Non-arithmetic type for right operand
Semantic error: derived metric my.bad_3: sample.aggregate.hullo * 1024: Non-arithmetic type for left operand
Semantic error: derived metric my.bad_4: <expr> + sample.string.hullo: Non-arithmetic type for right operand
Semantic error: derived metric my.bad_5: sample.aggregate.hullo - <expr>: Non-arithmetic type for left operand
Semantic error: derived metric my.bad_6: 1 + sample.string.hullo: Non-arithmetic type for right operand
Semantic error: derived metric my.bad_7: sample.string.hullo * 128: Non-arithmetic type for left operand
Error: my: Unknown metric name
