Generate String() methods for integer types by running go run golang.org/x/tools/cmd/stringer -type=YourTypeName.
Run the stringer tool with the -type flag pointing to your integer type to generate a String() method automatically.
go run golang.org/x/tools/cmd/stringer -type=ActualExprPropBits
This command scans the current package, finds the ActualExprPropBits type, and generates a _string.go file containing the String() method implementation.
Stringer is a tool that automatically writes code to turn your custom integer types into readable text. Instead of manually writing a long switch statement to map numbers to names, you run this tool once, and it creates the file for you. It is like having a robot fill out a form based on your existing code definitions.