lib: Use Nix's static scope checking, fix error message, optimize

Nix can perform static scope checking, but whenever code is inside
a `with` expression, the analysis breaks down, because it can't
know statically what's in the attribute set whose attributes were
brought into scope. In those cases, Nix has to assume that
everything works out.

Except it doesnt. Removing `with` from lib/ revealed an undefined
variable in an error message.

If that doesn't convince you that we're better off without `with`,
I can tell you that this PR results in a 3% evaluation performance
improvement because Nix can look up local variables by index.
This adds up with applications like the module system.

Furthermore, removing `with` makes the binding site of each
variable obvious, which helps with comprehension.

1 files changed, 51 insertions, 8 deletions

diff --git a/lib/modules.nix b/lib/modules.nix
index df3a2ad17e5fe..37e2e23ec12d4 100644
--- a/lib/modules.nix
+++ b/lib/modules.nix
@@ -1,12 +1,55 @@
 { lib }:
 
-with lib.lists;
-with lib.strings;
-with lib.trivial;
-with lib.attrsets;
-with lib.options;
-with lib.debug;
-with lib.types;
+let
+  inherit (lib.attrsets)
+    mapAttrsRecursiveCond
+    ;
+  inherit (lib.lists)
+    any all concatLists concatMap
+    count filter findFirst foldl foldl'
+    head imap1 length optional
+    reverseList sort
+    ;
+  inherit (lib.options)
+    isOption
+    mkOption
+    showDefs
+    showFiles
+    showOption
+    unknownModule
+    ;
+  inherit (lib.attrsets)
+    attrByPath
+    attrNames
+    catAttrs
+    getAttrFromPath
+    mapAttrs
+    mapAttrsToList
+    optionalAttrs
+    recursiveUpdate
+    setAttrByPath
+    toList
+    ;
+  inherit (lib.types)
+    types
+    ;
+  inherit (lib.trivial)
+    flip
+    id
+    isBool
+    isFunction
+    isString
+    min
+    warn
+    ;
+  inherit (lib.strings)
+    optionalString
+    ;
+  inherit (lib)
+    elem
+    isAttrs
+    ;
+in
 
 rec {
 
@@ -616,7 +659,7 @@ rec {
   fixupOptionType = loc: opt:
     let
       options = opt.options or
-        (throw "Option `${showOption loc'}' has type optionSet but has no option attribute, in ${showFiles opt.declarations}.");
+        (throw "Option `${showOption loc}' has type optionSet but has no option attribute, in ${showFiles opt.declarations}.");
       f = tp:
         let optionSetIn = type: (tp.name == type) && (tp.functor.wrapped.name == "optionSet");
         in