GroovyConsole reports "unexpected token" on method name after @Grab

The following script:

@Grab( group='org.codehaus.groovy.modules.http-builder', module='http-builder', version='0.5.1' )

println "x"

yields "unexpected token: println at line: 3, column: 1"

However, inserting "def z" in a line before println compiles correctly. Oddly, adding parenthesis:

@Grab( group='org.codehaus.groovy.modules.http-builder', module='http-builder', version='0.5.1' )

println ("x")

changes the error to: unexpected token: x at line: 3, column: 10

So, I expect there's something about the syntax of @Grab (or @?) that is allowing for the possibility of more text related to it such that the method 'println' is ambiguous but 'def' clearly terminates the @Grab and starts a new element. A minor thing, but confusing.