Glas (glass) and glass (ice cream) have very different pronounciations that you don't really mix up. Glas has an extended a, glass sounds just about the same as in english.
To an Aussie bogan like me I'd pronounce the two the same usually, I have to think of the difference as how an American says glass vs how an Englishman/Aussie might say glass
I haven't had the balls to try speaking Swedish yet so haven't asked to eat some glass yet