Read grammar.txt to find out why: A binary expression consists of `primary`
expressions and their definition is:
primary = simplePrimary (commandStart expr)
/ operatorB primary
/ routineExpr
/ rawTypeDesc
/ prefixOperator primary
Run
which does not include `if` or `case` or `try` expressions. Would it hurt to
add these? For this you need to analyse the first and follow sets of the
grammar rules. This is tedious to do manually so somebody should patch `tools /
grammar_nanny.nim` to do it automatically. PRs are welcome. ;-)
