UniqueExprs with same ID are resolved independently

[Rob Schluntz]

struct inner {
    int size;
};

struct outer {
    inner;
    int func;
};

int main() {
    outer o;
    o.[size, func];
}

Here, the aggregate portion of the tuple member expression is wrapped in a UniqueExpr so that the expression is only evaluated once, and rewritten as [UniqueExpr?(o).size, UniqueExpr?(o).func].

Currently, these UniqueExprs are resolved independently, so in this case the first becomes UniqueExpr(o.anon).size and the second becomes UniqueExpr(o).func. This approach needs to be modified so that all UniqueExprs with the same ID resolve to the same expression, and that resolution needs to take into account the context for all instances of the expression.

[Thierry Delisle]

Update code with missing inline keyword.

Unclear if this is still a problem.