lix/doc/manual/rl-next/source-positions-in-errors.md
eldritch horrors 87e6ac5eb7 Merge pull request #9753 from 9999years/print-value-on-type-error
Print the value in `value is X while a Y is expected` error

(cherry picked from commit 5f72a97092)
Change-Id: Idb4bc903ae59a0f5b6fb3b1da4d47970fe0a6efe
2024-03-09 00:05:41 -07:00

43 lines
784 B
Markdown

---
synopsis: Source locations are printed more consistently in errors
issues: 561
prs: 9555
---
Source location information is now included in error messages more
consistently. Given this code:
```nix
let
attr = {foo = "bar";};
key = {};
in
attr.${key}
```
Previously, Nix would show this unhelpful message when attempting to evaluate
it:
```
error:
… while evaluating an attribute name
error: value is a set while a string was expected
```
Now, the error message displays where the problematic value was found:
```
error:
… while evaluating an attribute name
at bad.nix:4:11:
3| key = {};
4| in attr.${key}
| ^
5|
error: expected a string but found a set: { }
```