Reusing a variable in a catch() expression makes the variable undeclared

[josephg]

This code:

try
  x = 3
catch x
  throw x

compiles to this:

try {
  x = 3;
} catch (x) {
  throw x;
}

... In which x is never declared locally.

[michaelficarra]

Looks like a bug to me. Simpler examples:

$ coffee -bpe 'try x = 3 catch x'
try {
  x = 3;
} catch (x) {

}
$ coffee -bpe 'try x = 3 catch y'
var x;
try {
  x = 3;
} catch (y) {

}

[jashkenas]

This patch should do the trick -- thanks for the bug report, and the great test case.