external.json

{
  "System.Collections.Generic": {
    "IReadOnlyList`2": {
      "P:Keys": "NotNull",
      "P:Values": "NotNull",
      "M:TryGetValue(`0,`1@)": [
        "Pure",
        ["ContractAnnotation", "=> true; => false, value: null"],
        { "key": "NotNull" }
      ],
      "M:ContainsKey(`0)": "Pure"
    }
  }
}

external.xml

  <member name="P:System.Collections.Generic.IReadOnlyDictionary`2.Keys">
    <attribute ctor="M:JetBrains.Annotations.NotNullAttribute.#ctor" />
  </member>
  <member name="P:System.Collections.Generic.IReadOnlyDictionary`2.Values">
    <attribute ctor="M:JetBrains.Annotations.NotNullAttribute.#ctor" />
  </member>
  <member name="M:System.Collections.Generic.IReadOnlyDictionary`2.ContainsKey(`0)">
    <attribute ctor="M:JetBrains.Annotations.PureAttribute.#ctor" />
  </member>
  <member name="M:System.Collections.Generic.IReadOnlyDictionary`2.TryGetValue(`0,`1@)">
    <attribute ctor="M:JetBrains.Annotations.PureAttribute.#ctor" />
    <attribute ctor="M:JetBrains.Annotations.ContractAnnotationAttribute.#ctor(System.String)">
        <argument>=&gt;true; =&gt;false, value: null</argument>
    </attribute>
    <parameter name="key">
      <attribute ctor="M:JetBrains.Annotations.NotNullAttribute.#ctor" />
    </parameter>
  </member>