Pieces of idioms can undergo pronominalization and ellipsis, as many have observed (Nunberg, Sag and Wasow 1994; McCawley 1988, Bruening 2015; a.o.). Building on these observations, we discuss a novel paradigm involving anaphoric relations in clausal idioms, where pronominalization of the subject and ellipsis need to co-occur (cf. (1b-d)). We are concerned with two questions: how the idiomatic interpretation becomes available under pronominalization and VP ellipsis (1b), and why there is a co-occurrence restriction, given that no such restriction appears to apply in non-idiomatic contexts.

(1) Alex: When the news got out, the shit hit the fan. Ben: No, ... a. ... the shit didn't hit the fan. [−Pron., −VPE] b. ... it didn't. [+Pron., +VPE] c. ... #it didn't hit the fan. [+Pron., −VPE] d. ... #the shit didn't. [−Pron., +VPE]

We argue that this paradigm informs theories of pronoun and ellipsis: assuming that clausal idioms are not (fully) compositional, it lends new support (i) for the idea that pronouns can be derived from full noun phrases (Postal 1969, Elbourne 2001), and (ii) for an identity condition on ellipsis that takes into account the content of a syntactic chunk larger than the elided constituent (e.g. Gengel 2007, pace Merchant 2001). We conclude with a pragmatic account of this co-occurrence restriction.