Incorrect scalar propagation w/ multi-return functions

foo = function(matrix[double] A) return (Double minsc, matrix[double] B) {
  while(FALSE) {} # prevent inlining
  minsc = min(A);
  B = A + 7;
}

X = seq(1,7);
minsc = -Inf;
if( avg(X) <= 5 ) {
  [minsc, X] = foo(X)
}

# bug: minsc was incorrectly propagated as -Inf, leading to -Inf instead of 2
R = as.matrix(minsc + 1);
write(R, $1);