Confusing Results from diff

Question

I got the following results from diff:

@@ -4479,7 +4479,7 @@
         || AddPrintCheckParameters(TRUE)
         || AddRecipeDefaults(TRUE)
         || AddRepeatScanPass(TRUE)
-        || AddVirgoFlag(TRUE)        
+        || AddVirgoFlag(TRUE)
         || AddAttrPatchSize(TRUE)
         || AddDualSensParameters(TRUE)
         || AddMDATDensitySP(TRUE)

Seems that it suggesting me to delete and add the same line. Why?

Answer 1

By selecting both lines with the mouse to they are highlighted, I can clearly see that the first (deleted) line has trailing spaces that the second does not.

If you use diff -w this difference would be ignored by diff.