disable nested struct for array and map type

[kesonan]

1. disable nested struct for array and map type, the follow types all are invalid:

type Demo {
  Foo {} `json:"foo"` // invalid types: unsupported empty nestedt struct
  Bar []{} `json:"foo"` // invalid types: slice elements unsupported nested struct
  Bar [2]{} `json:"foo"` // invalid types: array elements unsupported nested struct
  Bar map[{}]string `json:"foo"` // invalid types: map key elements unsupported nested struct
  Bar map[int]{} `json:"foo"` // invalid types: map value elements unsupported nested struct
}

[codecov]

Codecov Report

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Project coverage is 95.09%. Comparing base (8690859) to head (f858c87).
Report is 71 commits behind head on master.

Additional details and impacted files

see 255 files with indirect coverage changes