Stop instantiating parse_value in MapKey::deserialize_any #388
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The parse_value method is the most expensive method in serde_json in terms of compile time. Before this change, we were instantiating it twice for every derive(Deserialize) struct because every struct has two different Visitor impls -- one for the key type and one for the struct overall -- see https://serde.rs/deserialize-struct.html. This improves compile time of json-benchmark by 20%.
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The parse_value method is the most expensive method in serde_json in terms of compile time. Before this change, we were instantiating it twice for every derive(Deserialize) struct because every struct has two different Visitor impls -- one for the key type and one for the struct overall -- see https://serde.rs/deserialize-struct.html.
This improves compile time of json-benchmark in release mode by 20%. #313