Souffle Datalog has a pattern called a base type, which is structurally the same as a primitive type, but different base types will not implicitly cast to each other. Below is an example of the base type syntax:
.type Country <: symbol
The intellij datalog plugin appears to not recognize the <: symbol and highlights it with a red squiggly underline.
Should be fixed in the next update. The update will be available in 2 days or so via the IDEs plugin manager. You can get it earlier by downloading and installing it directly from the releases page.
Souffle Datalog has a pattern called a base type, which is structurally the same as a primitive type, but different base types will not implicitly cast to each other. Below is an example of the base type syntax:
The intellij datalog plugin appears to not recognize the <: symbol and highlights it with a red squiggly underline.