<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto">Yes - if you look at the number types, you will find different number types and not integer types are providing support that’s not in Integer, so compiler is giving safest assumption.<br><br><div dir="ltr">Sent from my iPhone</div><div dir="ltr"><br><blockquote type="cite">On Apr 17, 2020, at 12:56 PM, Alexander Chen <alexander@chenjia.nl> wrote:<br><br></blockquote></div><blockquote type="cite"><div dir="ltr"><div style="font-family:Arial; font-size:13px;">hi,<div><br></div><div>Prelude> u = undefined</div><div>Prelude> k :: (Ord a, Num b) => a -> b -> a; k = u</div><div><br></div><div>Prelude> :t k 1 2 </div><div>k 1 2 :: (Ord a, Num a) => a</div><div><br></div><div>Prelude> :t k (1 :: Integer) 2</div><div>k (1 :: Integer) 2 :: Integer</div><div><br></div><div>In the first version the compiler is not really pushed so it simply gives back the type class constriction it has to adhere to. While in the second it is pushed to give an more specific answer and thus the :: Integer.</div><div><br></div><div>Question:</div><div>Is this train of thought correct? </div><div><br><br><div><div style="font-family:Arial; font-size:13px;"><br></div></div></div></div><span>_______________________________________________</span><br><span>Beginners mailing list</span><br><span>Beginners@haskell.org</span><br><span>http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners</span><br></div></blockquote></body></html>