Module level variable shadowing

[bearophile via Digitalmars-d]

While I try to minimize the number of module-level variables in D 
code, sometimes they are present, and sometimes I have problems 
(bugs) caused by unwanted shadowing of global names (or sometimes 
more generally, names from outer scopes, but this is less common):

int x = 1;
// ...
void foo() {
    // ...
    int x = 2;
    // ...
    writeln(x);
}


Can't we find a way to avoid/find such kind of bugs? (It's not a 
problem of mutability, because the same problem happens with 
immutable variables.) I have hit this bug several times.

The simplest way to avoid that kind of bugs is give a "shadowing 
global x error" (similar to the shadowing errors D gives with 
foreach and with statements). But this breaks most existing D 
code.

Bye,
bearophile