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60 lines
2.7 KiB
60 lines
2.7 KiB
5 years ago
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(*
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*)
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open! IStd
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let is_object_nullability_self_explanatory ~object_expression object_origin =
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(* Fundamentally, object can be of two kinds:
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1. Indirect: local variable that was instantiated before.
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In this case, normally origin is NOT trivial
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(because for complex flows it might be tricky to figure out where the offending
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initialization came from, and it is a good idea to at least point to the line).
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2. Direct: some sort of expression. In this case, this expression itself is often
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self-explanatory and it is OK to be offended.Infer
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NOTE: code below is heuristic, it indends to cover most practical cases and does not try
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to be 100% precise.
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*)
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match object_origin with
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| TypeOrigin.NullConst _ ->
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(* Expect either a local variable or null literal (latter case is trivial) *)
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String.equal object_expression "null"
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| TypeOrigin.MethodParameter {mangled} ->
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(* Either local variable or literally parameter. In latter case, its nullability is
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self-explanatory because the user can quickly see the current method signature.
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*)
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let param_name = Mangled.to_string mangled in
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String.equal object_expression param_name
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| TypeOrigin.Field {field_name} ->
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(* Either local variable or expression like `<smth>.field_name`. Latter case is trivial:
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the user can quickly go to field_name definition and see if its annotation. *)
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let field_name_str = Typ.Fieldname.to_flat_string field_name in
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String.is_suffix object_expression ~suffix:field_name_str
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| TypeOrigin.MethodCall {pname} ->
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(* TODO: take into account external models as well *)
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let is_modelled = Models.is_modelled_for_nullability_as_internal pname in
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if is_modelled then (* This is non-trivial and should always be explained to the user *)
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false
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else
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(* Either local variable or expression like <smth>.method_name(...).
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Latter case is self-explanatory: it is easy to the user to jump to definition
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and check out the method annotation.
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*)
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let method_name = Typ.Procname.to_simplified_string pname in
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String.is_suffix object_expression ~suffix:method_name
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(* These cases are not yet supported because they normally mean non-nullable case, for which
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we don't render important messages yet.
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*)
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| TypeOrigin.NonnullConst _
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| TypeOrigin.This
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| TypeOrigin.New
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| TypeOrigin.ArrayLengthResult
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| TypeOrigin.ArrayAccess
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| TypeOrigin.InferredNonnull _
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| TypeOrigin.OptimisticFallback
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| TypeOrigin.Undef ->
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false
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