- (flet ((check-version (impl vers)
- (when (string= impl implementation)
- (unless (= version vers)
- (error "~S was compiled for fasl file format version ~S, ~
- but we need version ~S."
+ (flet ((check-version (variant possible-implementation needed-version)
+ (when (string= possible-implementation implementation)
+ (unless (= version needed-version)
+ (error "~@<~S was compiled for ~A fasl file format ~
+ version ~D, but we need version ~D.~:@>"