Update .travis.osx.yml

Turn off 'MEMCHECK' for OSX build.
[skip ci]
Fix typo

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Improve application type mismatch errors. We also show the implicit arguments (not just their types)

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Improve elaborator error messages

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Improve elaborator error messages