declare name context pattern expander declares the extension names name for
context.
expander is responsible for producing the code to replace the extension in the
AST. It receives as argument:
loc: the location of the enclosing node. For instance for expression it is the
pexp_loc fieldpath: the current module pathInline the result of the expansion into its parent. Only works for these contexts:
class_fieldclass_type_fieldsignature_itemstructure_item