Ppx_expectSourceval maybe_string_payload :
Base.unit ->
(Ppxlib.payload,
located_payload:
(Ppx_expect_runtime.Payload.t * Ppx_expect_runtime.Compact_loc.t)
Base.option ->
'a,
'a)
Ppxlib.Ast_pattern.tMatches an extension point payload that is either empty or a single string literal. The extracted information is the Payload.t and its Compact_loc.t representing the string literal from the payload if present, or {||} and None if not.