Spec should tighten restrictions on number of parameter type coercions.

[cscott]

The spec doesn't explicitly mention in section 5.1 that there must be exactly as many parameter type coercion statements as there are formal parameters. That is, the following is invalid:

function f(x, y) {
  x = x|0;
  x = x|0;
  y = x|0;
  return 42;
}

The other case is a little more obviously invalid (the spec says, "Every parameter in an asm.js function is provided with an explicit type annotation"):

function f(x) {
   return 42;
}

(My asm.js parser initially used a very generous parsing rule which required backtracing and allowed repeated coercions like the first example; only after reading the AsmJS.cpp source did I realize this was unnecessary.)

It should be obvious that

function(x,y) {
  x = x|0, y = y|0;
  return 42;
}

is also invalid.

[timmutton]

It might also be worth mentioning that x |= 0 is also not a valid coercion

[ghost]

I think this is fixed now. Section 6.4 establishes the correspondence between parameters and parameter type annotation by using the same identifier sequence (x...), later saying "by mapping each each parameter x to its corresponding parameter type annotation" and then adding "annotations must appear in the same order as the parameters".