internal: remove unnecessary Pos methods

adt.BuiltinValidator had a Pos method which was never used.

pkg.CallCtxt had a Pos method which was used within the same package,
so inline the three uses instead, given its simplicity.

Signed-off-by: Daniel Martí <[e-mail]>
Change-Id: I23d1ed9e4daf2a738ebe31d55e8e87ce52e40aed
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1227395
Reviewed-by: Matthew Sackman <[e-mail]>
TryBot-Result: CUEcueckoo <[e-mail]>

internal/core/adt/expr.go

···
 	return x.Src.Source()
 }
 
-func (x *BuiltinValidator) Pos() token.Pos {
-	return Pos(x)
-}
-
 func (x *BuiltinValidator) Kind() Kind {
 	return x.Builtin.Params[0].Kind()
 }

internal/pkg/builtin.go

···
 	case string, fmt.Stringer:
 		// A string or a stringer likely used as a panic value.
 		ret = wrapCallErr(call, &adt.Bottom{
-			Err: errors.Newf(call.Pos(), "%s", err),
+			Err: errors.Newf(call.ctx.Pos(), "%s", err),
 		})
 	default:
 		// Some other value used when panicking; likely a bug.
 		ret = wrapCallErr(call, &adt.Bottom{
-			Err: errors.Newf(call.Pos(), "BUG: non-stringifiable %T", err),
+			Err: errors.Newf(call.ctx.Pos(), "BUG: non-stringifiable %T", err),
 		})
 	}
 	return ret

internal/pkg/context.go

···
 	"github.com/cockroachdb/apd/v3"
 
 	"cuelang.org/go/cue"
-	"cuelang.org/go/cue/token"
 	"cuelang.org/go/internal/core/adt"
 	"cuelang.org/go/internal/value"
 )
···
 	Ret     any
 
 	args []adt.Value
-}
-
-func (c *CallCtxt) Pos() token.Pos {
-	return c.ctx.Pos()
 }
 
 func (c *CallCtxt) Name() string {

internal/pkg/errors.go

···
 	case error:
 		errs = errors.Promote(x, "")
 	}
-	vErr := c.ctx.NewPosf(c.Pos(), format, args...)
+	vErr := c.ctx.NewPosf(c.ctx.Pos(), format, args...)
 	c.Err = &callError{&adt.Bottom{Code: code, Err: errors.Wrap(vErr, errs)}}
 }