This is a more correct representation than using "Equality" introduced
in r238942 which was a quick fix to solve an actual regression.
According to the typescript spec, arrows behave like "low-precedence"
assignments.
Before:
var a = a.aaaaaaa((a: a) => aaaaaaaaaaaaaaaaaaaaa(bbbbbbbbb) &&
aaaaaaaaaaaaaaaaaaaaa(bbbbbbb));
After:
var a = a.aaaaaaa((a: a) => aaaaaaaaaaaaaaaaaaaaa(bbbbbbbbb) &&
aaaaaaaaaaaaaaaaaaaaa(bbbbbbb));
llvm-svn: 239137