Better error for unimported constructor (GHC-31891)
## Summary
When we use an un-imported constructor when its type is in-scope and has the same name, we get an error that warns us that we are using a type instead of a term. Whenever I get this error it's simply because I've forgotten to import the constructor. That's fine for me, but I think this would likely trip up a beginner.
It would be better if GHC suggested that we import the constructor.
## Steps to reproduce
```hs
module A where
data A = A
```
```hs
module B where
import A (A)
test = A
```
Then compile it using `ghc A.hs B.hs`.
And you will get this error:
```
[1 of 2] Compiling A ( A.hs, A.o )
[2 of 2] Compiling B ( B.hs, B.o )
B.hs:5:8: error: [GHC-31891]
• Illegal term-level use of the type constructor or class ‘A’
• imported from ‘A’ at B.hs:3:11
(and originally defined at A.hs:3:1-10)
• Add ‘A’ to the import list in the import of ‘A’ (at B.hs:3:1-12).
• In the expression: A
In an equation for ‘test’: test = A
|
5 | test = A
|
```
## Expected behavior
Suggest that the user imports this type, compare if we don't import the type at all:
```
[2 of 2] Compiling B ( B.hs, B.o )
B.hs:5:8: error: [GHC-88464]
Data constructor not in scope: A
Suggested fix:
Add ‘A’ to the import list in the import of ‘A’ (at B.hs:3:1-11).
|
5 | test = A
|
```
## Environment
* GHC version used: GHC-9.4.7, I think also happens with HEAD
issue