default FU=<v>fu</v> FOO=<v>foo</v> VAR=<v></v>
two FU=<v>bar</v> FOO=<v>goo</v> VAR=<v></v>
immutable FU='bar'
immutable FOO='goo'
three FU=<v>bar</v> FOO=<v>goo</v> VAR=<v></v>
four FU=<v>bar</v> FOO=<v>goo</v> VAR=<v>Internal</v>
five FU=<v>bar</v> FOO=<v>goo</v> VAR=<v>Internal</v>
five v=is x k=is x
six v=is y k=is y
show-v v=override k=override
exit status 0