stdenv/check-meta: verify that licenses aren't derivations

Among other things, "zlib" is a license, and it's difficult to debug the eval
errors that occur when that derivation gets added to meta.licenses.

pkgs/stdenv/generic/check-meta.nix

@@ -16,12 +16,10 @@ let
     filter
     findFirst
     getName
-    isDerivation
     length
     concatMap
     mutuallyExclusive
     optional
-    optionalString
     isAttrs
     isString
     warn
@@ -308,15 +306,17 @@ let
         union
         int
         attrs
-        attrsOf
         any
         listOf
         bool
         record
+        intersection
+        not
+        derivation
         ;
       platforms = listOf (union [
         str
-        (attrsOf any)
+        attrs
       ]); # see lib.meta.platformMatch
     in
     record {
@@ -338,7 +338,10 @@ let
         let
           # TODO disallow `str` licenses, use a module
           licenseType = union [
-            (attrsOf any)
+            (intersection [
+              attrs
+              (not derivation)
+            ])
             str
           ];
         in
@@ -347,9 +350,9 @@ let
           licenseType
         ];
       sourceProvenance = listOf attrs;
-      maintainers = listOf (attrsOf any); # TODO use the maintainer type from lib/tests/maintainer-module.nix
-      nonTeamMaintainers = listOf (attrsOf any); # TODO use the maintainer type from lib/tests/maintainer-module.nix
-      teams = listOf (attrsOf any); # TODO similar to maintainers, use a teams type
+      maintainers = listOf attrs; # TODO use the maintainer type from lib/tests/maintainer-module.nix
+      nonTeamMaintainers = listOf attrs; # TODO use the maintainer type from lib/tests/maintainer-module.nix
+      teams = listOf attrs; # TODO similar to maintainers, use a teams type
       priority = int;
       pkgConfigModules = listOf str;
       inherit platforms;

pkgs/stdenv/generic/meta-types.nix

@@ -10,6 +10,7 @@ let
     isInt
     isAttrs
     isList
+    isDerivation
     all
     any
     attrNames
@@ -103,6 +104,11 @@ lib.fix (self: {
           ) (attrNames attrs);
     };
 
+  derivation = {
+    name = "derivation";
+    verify = isDerivation;
+  };
+
   listOf =
     t:
     assert isTypeDef t;
@@ -141,6 +147,29 @@ lib.fix (self: {
       verify = v: any (func: func v) funcs;
     };
 
+  intersection =
+    types:
+    assert all isTypeDef types;
+    let
+      # Store a list of functions so we don't have to pay the cost of attrset lookups at runtime.
+      funcs = map (t: t.verify) types;
+    in
+    {
+      name = "intersection<${concatStringsSep "," (map (t: t.name) types)}>";
+      verify = v: all (func: func v) funcs;
+    };
+
+  not =
+    t:
+    assert isTypeDef t;
+    let
+      inherit (t) verify;
+    in
+    {
+      name = "not<${t.name}>";
+      verify = v: !(verify v);
+    };
+
   enum =
     values:
     assert isList values && all isString values;