fix(tvix/eval): update identifier quoting to match cppnix 2.17

In cppnix 2.17, commit b72bc4a972fe568744d98b89d63adcd504cb586c, the
libexpr pretty-printing routine was fixed so that it would no longer
pretty-print attrsets with keywords in their attrnames incorrectly.

This commit implements the corresponding fix for tvix, fixes our
tests to work with cppnix>=2.17 oracles, and expands our test cases
to cover all the keywords.

Change-Id: I4b51389cd3a9c44babc8ab2a84b383b7b0b116ca
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9283
Autosubmit: Adam Joseph <adam@westernsemico.com>
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI

tvix/eval/src/tests/tvix_tests/eval-okay-identifier-formatting.exp

@@ -1 +1 @@
-{ "'quoted'" = false; "-20°" = false; "2normal" = false; "45 44 43-'3 2 1" = false; "9front" = false; Very2Normal = true; VeryNormal = true; _'12 = true; "_'12.5" = false; __internal = true; _internal = true; abort = true; assert = true; "attr.path" = false; false = true; foldl' = true; normal = true; normal2 = true; null = true; or = true; throw = true; true = true; x = true; x' = true; x'' = true; "😀" = false; }
+{ "'quoted'" = false; "-20°" = false; "2normal" = false; "45 44 43-'3 2 1" = false; "9front" = false; Very2Normal = true; VeryNormal = true; _'12 = true; "_'12.5" = false; __internal = true; _internal = true; abort = true; "assert" = false; "attr.path" = false; "else" = false; false = true; foldl' = true; "if" = false; "in" = false; "inherit" = false; "let" = false; normal = true; normal2 = true; null = true; or = true; "rec" = false; "then" = false; throw = true; true = true; "with" = false; x = true; x' = true; x'' = true; "😀" = false; }

tvix/eval/src/tests/tvix_tests/eval-okay-identifier-formatting.nix

@@ -1,3 +1,6 @@
+# Note: the attribute values in this set aren't just dummies!  They
+# are booleans which indicate whether or not the corresponding
+# attrname is valid without quotification.
 {
   __internal = true;
   _internal = true;
@@ -15,7 +18,7 @@
   false = true;
   null = true;
   or = true;
-  "assert" = true; # -ish
+  "assert" = false;
   throw = true;
   abort = true;
 
@@ -27,4 +30,13 @@
   "'quoted'" = false;
   "_'12.5" = false;
   "😀" = false;
+
+  "if" = false;
+  "then" = false;
+  "else" = false;
+  "with" = false;
+  "let" = false;
+  "in" = false;
+  "rec" = false;
+  "inherit" = false;
 }

tvix/eval/src/tests/tvix_tests/identity-quoted-attrname-assert.nix

@@ -0,0 +1 @@
+{ "assert" = true; }

tvix/eval/src/tests/tvix_tests/identity-quoted-attrname-else.nix

@@ -0,0 +1 @@
+{ "else" = true; }

tvix/eval/src/tests/tvix_tests/identity-quoted-attrname-if.nix

@@ -0,0 +1 @@
+{ "if" = true; }

tvix/eval/src/tests/tvix_tests/identity-quoted-attrname-in.nix

@@ -0,0 +1 @@
+{ "in" = true; }

tvix/eval/src/tests/tvix_tests/identity-quoted-attrname-inherit.nix

@@ -0,0 +1 @@
+{ "inherit" = true; }

tvix/eval/src/tests/tvix_tests/identity-quoted-attrname-let.nix

@@ -0,0 +1 @@
+{ "let" = true; }

tvix/eval/src/tests/tvix_tests/identity-quoted-attrname-rec.nix

@@ -0,0 +1 @@
+{ "rec" = true; }

tvix/eval/src/tests/tvix_tests/identity-quoted-attrname-then.nix

@@ -0,0 +1 @@
+{ "then" = true; }

tvix/eval/src/tests/tvix_tests/identity-quoted-attrname-with.nix

@@ -0,0 +1 @@
+{ "with" = true; }