$ perl -le " f(1); sub f{warn@_} "
1 at -e line 1.

$ perl -le " f 1 ; sub f{warn@_} "
Number found where operator expected at -e line 1, near "f 1"
        (Do you need to predeclare f?)
syntax error at -e line 1, near "f 1"
Execution of -e aborted due to compilation errors.

$ perl -le " sub f; f 1 ; sub f{warn@_} "
1 at -e line 1.