> In Go (as in most programming languages) it's not true that the assignment "a = b" implies that "b == foo => a == foo", if a and b are different types.

While I haven't counted and compared, I suspect that in most programming languages, "a=b" being a non-error implies that either a and b are the same type and value, or that a and b are values that, if they are of different and comparable types, will compare equal.

There are certainly popular languages that do it the way you describe, but I don't think most languages do.