[villaverde82]

restcheck_schema:intersection/2, when merging two object schemas (e.g. in an allOf), keeps only the properties present in both schemas, but takes the union of their required lists. Any property declared in just one of them is dropped while still being required, so restcheck_triq:object/2 can't find it in properties and crashes with badkey.

Example:

Pet:
type: object
properties:
name: {type: string}
age: {type: integer}
required: [name, age]

Dog:
allOf:
- $ref: '#/components/schemas/Pet'
- type: object
properties:
age: {type: integer, minimum: 0}
bark: {type: boolean}
required: [bark]

Current result: properties = {age: {type: integer, minimum: 0}}, required = [name, age, bark] -> {badkey, <<"name">>}

Since allOf requires an instance to satisfy both schemas, the fix takes the union of the properties. Properties present in only one schema (name, bark) are kept as they are. Properties present in both (age) still have their schemas intersected, so they must satisfy both (maps:merge_with with intersection/1).

Expected result: properties = {name: {type: string}, age: {type: integer, minimum: 0}, bark: {type: boolean}}, required = [name, age, bark]