Q: How to handle the Implicit search problem too large. error?

[error]    |Implicit search problem too large.
[error]    |an implicit search was terminated with failure after trying 100000 expressions.
[error]    |The root candidate for the search was:
[error]    |
[error]    |  given instance given_Decoder_P in object Decoder  for  ldbc.dsl.codec.Decoder[City]}

A: When Implicit search problem too large. occurs, you can solve it by increasing the recursion depth using the -Ximplicit-search-limit option.

When the Implicit search problem too large. error occurs, you can often solve the problem by increasing the search limit compilation option. You can set any value for the number indicating the recursion depth.

scalacOptions += "-Ximplicit-search-limit:100000"

However, expanding the limit through this option may lead to increased compilation time. In that case, you can also solve it by manually constructing the required type as shown below:

given Decoder[City] = Decoder.derived[City]
// Or given Decoder[City] = (Decoder[Int] *: Decoder[String] *: Decoder[Int] *: ....).to[City]
given Encoder[City] = Encoder.derived[City]
// Or given Encoder[City] = (Encoder[Int] *: Encoder[String] *: Encoder[Int] *: ....).to[City]

Alternatively, you can solve it by using Codec to combine Encoder and Decoder.

given Codec[City] = Codec.derived[City]
// Or given Codec[City] = (Codec[Int] *: Codec[String] *: Codec[Int] *: ....).to[City]

References

• Custom Data Type