dmd.attr-inference-diag.dd

Better error message when attribute inference fails down the call stack

When a function fails to infer a function attribute, all callers of that function also fail to infer the attribute.
The resulting error message only points to the top most function with the explicit attribute:

---
void main() @nogc
{
    fun();
}

auto fun()
{
    funImpl();
}

auto funImpl()
{
    int[] a = [1, 2, 3];
}
---

$(CONSOLE
app.d(4): Error: `@nogc` function `D main` cannot call non-@nogc function `app.fun`
)

This doesn't tell the underlying reason why `fun` wasn't inferred `@nogc`, and led to use of [workarounds to get better information](https://www.schveiguy.com/blog/2023/02/spelunking-attribute-inference-in-d/).
The new error message will point to the function which failed to infer the attribute:

$(CONSOLE
app.d(4): Error: `@nogc` function `D main` cannot call non-@nogc function `app.fun`
app.d(7):        which calls `app.funImpl`
app.d(14):        which wasn't inferred `@nogc` because of:
app.d(14):        array literal in `@nogc` function `app.funImpl` may cause a GC allocation
)

Note: this was already implemented for `@safe` since 2.101, but it has now been extended to `@nogc`, `nothrow`, and `pure`.