Merge pull request #9753 from 9999years/print-value-on-type-error

Print the value in `value is X while a Y is expected` error

doc/manual/rl-next/print-value-in-type-error.md

@@ -0,0 +1,23 @@
+---
+synopsis: Type errors include the failing value
+issues: #561
+prs: #9753
+---
+
+In errors like `value is an integer while a list was expected`, the message now
+includes the failing value.
+
+Before:
+
+```
+       error: value is a set while a string was expected
+```
+
+After:
+
+```
+       error: expected a string but found a set: { ghc810 = «thunk»;
+       ghc8102Binary = «thunk»; ghc8107 = «thunk»; ghc8107Binary = «thunk»;
+       ghc865Binary = «thunk»; ghc90 = «thunk»; ghc902 = «thunk»; ghc92 = «thunk»;
+       ghc924Binary = «thunk»; ghc925 = «thunk»;  «17 attributes elided»}
+```

doc/manual/rl-next/source-positions-in-errors.md

@@ -38,5 +38,5 @@ error:
              |           ^
             5|
 
-       error: value is a set while a string was expected
+       error: expected a string but found a set
 ```

doc/manual/rl-next/with-error-reporting.md

@@ -8,7 +8,7 @@ prs: 9658
 Previously an incorrect `with` expression would report no position at all, making it hard to determine where the error originated:
 
 ```
-nix-repl> with 1; a  
+nix-repl> with 1; a
 error:
        … <borked>
 
@@ -27,5 +27,5 @@ error:
             1| with 1; a
              | ^
 
-       error: value is an integer while a set was expected
+       error: expected a set but found an integer
 ```