[Issue 23152] New: Bad diagnostic for variable used as a type

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=23152

          Issue ID: 23152
           Summary: Bad diagnostic for variable used as a type
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Keywords: diagnostic
          Severity: regression
          Priority: P1
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: b2.temp at gmx.com

The error for

```
struct S1 {}
struct S2 { S1 S1; }  
```

is

> a7F65CC3F01F0.d:2:16: Error: circular reference to variable `a7F65CC3F01F0.S2.S1`

I believe the right error should be

> a7F65CC3F01F0.d:2:16: Error: variable `a7F65CC3F01F0.S2.S1` is used as a type

A quick verification on run.dlang.io shows that this was the case in the past:

---
Up to      2.062  : Failure with output: Error: unrecognized switch '-main'
2.063   to 2.064  : Failure with output:
-----
onlineapp.d(2): Error: circular reference to 'onlineapp.S2.S1'
onlineapp.d(2): Error: S1 is used as a type
-----

           2.065.0: Failure with output: onlineapp.d(2): Error: circular
reference to 'onlineapp.S2.S1'
2.066.1 to 2.071.2: Failure with output:
-----
onlineapp.d(2): Error: circular reference to 'onlineapp.S2.S1'
onlineapp.d(2): Error: S1 is used as a type
-----

2.072.2 to 2.078.3: Failure with output: onlineapp.d(2): Error: circular
reference to variable 'onlineapp.S2.S1'
Since      2.079.1: Failure with output: onlineapp.d(2): Error: circular
reference to variable `onlineapp.S2.S1`
---

but since 2.072.2 among the two messages only the less relevant is output

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