Merge commit '432fc2d9a67f92e05438dff5fdc2b39d33f77997'

# Conflicts:
#	nixpkgs/pkgs/applications/editors/emacs/elisp-packages/elpa-generated.nix
#	nixpkgs/pkgs/applications/networking/mailreaders/thunderbird/default.nix
#	nixpkgs/pkgs/applications/window-managers/sway/default.nix
#	nixpkgs/pkgs/build-support/rust/default.nix
#	nixpkgs/pkgs/development/go-modules/generic/default.nix

17 files changed, 164 insertions, 46 deletions

diff --git a/nixpkgs/lib/attrsets.nix b/nixpkgs/lib/attrsets.nix
index 0ce3aaeca452..5c787940cb0c 100644
--- a/nixpkgs/lib/attrsets.nix
+++ b/nixpkgs/lib/attrsets.nix
@@ -243,6 +243,10 @@ rec {
   /* Call a function for each attribute in the given set and return
      the result in a list.
 
+     Type:
+       mapAttrsToList ::
+         (String -> a -> b) -> AttrSet -> [b]
+
      Example:
        mapAttrsToList (name: value: name + value)
           { x = "a"; y = "b"; }
diff --git a/nixpkgs/lib/customisation.nix b/nixpkgs/lib/customisation.nix
index 37a7951896b0..c17cb0d0f8e5 100644
--- a/nixpkgs/lib/customisation.nix
+++ b/nixpkgs/lib/customisation.nix
@@ -219,16 +219,17 @@ rec {
 
   /* Like the above, but aims to support cross compilation. It's still ugly, but
      hopefully it helps a little bit. */
-  makeScopeWithSplicing = splicePackages: newScope: otherSplices: keep: f:
+  makeScopeWithSplicing = splicePackages: newScope: otherSplices: keep: extra: f:
     let
-      spliced = splicePackages {
+      spliced0 = splicePackages {
         pkgsBuildBuild = otherSplices.selfBuildBuild;
         pkgsBuildHost = otherSplices.selfBuildHost;
         pkgsBuildTarget = otherSplices.selfBuildTarget;
         pkgsHostHost = otherSplices.selfHostHost;
         pkgsHostTarget = self; # Not `otherSplices.selfHostTarget`;
         pkgsTargetTarget = otherSplices.selfTargetTarget;
-      } // keep self;
+      };
+      spliced = extra spliced0 // spliced0 // keep self;
       self = f self // {
         newScope = scope: newScope (spliced // scope);
         callPackage = newScope spliced; # == self.newScope {};
@@ -239,6 +240,7 @@ rec {
           newScope
           otherSplices
           keep
+          extra
           (lib.fixedPoints.extends g f);
         packages = f;
       };
diff --git a/nixpkgs/lib/default.nix b/nixpkgs/lib/default.nix
index 50320669e280..ccae0bbc3ab4 100644
--- a/nixpkgs/lib/default.nix
+++ b/nixpkgs/lib/default.nix
@@ -66,8 +66,9 @@ let
       stringLength sub substring tail trace;
     inherit (self.trivial) id const pipe concat or and bitAnd bitOr bitXor
       bitNot boolToString mergeAttrs flip mapNullable inNixShell isFloat min max
-      importJSON importTOML warn info showWarnings nixpkgsVersion version mod compare
-      splitByAndCompare functionArgs setFunctionArgs isFunction toHexString toBaseDigits;
+      importJSON importTOML warn warnIf info showWarnings nixpkgsVersion version
+      mod compare splitByAndCompare functionArgs setFunctionArgs isFunction
+      toHexString toBaseDigits;
     inherit (self.fixedPoints) fix fix' converge extends composeExtensions
       composeManyExtensions makeExtensible makeExtensibleWithCustomName;
     inherit (self.attrsets) attrByPath hasAttrByPath setAttrByPath
diff --git a/nixpkgs/lib/flake.nix b/nixpkgs/lib/flake.nix
new file mode 100644
index 000000000000..f05bd40960a8
--- /dev/null
+++ b/nixpkgs/lib/flake.nix
@@ -0,0 +1,5 @@
+{
+  description = "Library of low-level helper functions for nix expressions.";
+
+  outputs = { self }: { lib = import ./lib; };
+}
diff --git a/nixpkgs/lib/licenses.nix b/nixpkgs/lib/licenses.nix
index 88d598d92079..3c4323e3d960 100644
--- a/nixpkgs/lib/licenses.nix
+++ b/nixpkgs/lib/licenses.nix
@@ -346,6 +346,11 @@ lib.mapAttrs (n: v: v // { shortName = n; }) ({
     fullName = "Unspecified free software license";
   };
 
+  ftl = spdx {
+    spdxId = "FTL";
+    fullName = "Freetype Project License";
+  };
+
   g4sl = {
     fullName = "Geant4 Software License";
     url = "https://geant4.web.cern.ch/geant4/license/LICENSE.html";
@@ -734,6 +739,12 @@ lib.mapAttrs (n: v: v // { shortName = n; }) ({
     free = false;
   };
 
+  stk = {
+    shortName = "stk";
+    fullName = "Synthesis Tool Kit 4.3";
+    url = https://github.com/thestk/stk/blob/master/LICENSE;
+  };
+
   tcltk = spdx {
     spdxId = "TCL";
     fullName = "TCL/TK License";
@@ -760,6 +771,11 @@ lib.mapAttrs (n: v: v // { shortName = n; }) ({
     # channel and NixOS images.
   };
 
+  unicode-dfs-2015 = spdx {
+    spdxId = "Unicode-DFS-2015";
+    fullName = "Unicode License Agreement - Data Files and Software (2015)";
+  };
+
   unicode-dfs-2016 = spdx {
     spdxId = "Unicode-DFS-2016";
     fullName = "Unicode License Agreement - Data Files and Software (2016)";
diff --git a/nixpkgs/lib/meta.nix b/nixpkgs/lib/meta.nix
index 2e83c4247ddf..bc04394dcf0b 100644
--- a/nixpkgs/lib/meta.nix
+++ b/nixpkgs/lib/meta.nix
@@ -87,4 +87,16 @@ rec {
         then { system = elem; }
         else { parsed = elem; };
     in lib.matchAttrs pattern platform;
+
+  /* Check if a package is available on a given platform.
+
+     A package is available on a platform if both
+
+       1. One of `meta.platforms` pattern matches the given platform.
+
+       2. None of `meta.badPlatforms` pattern matches the given platform.
+  */
+  availableOn = platform: pkg:
+    lib.any (platformMatch platform) pkg.meta.platforms &&
+    lib.all (elem: !platformMatch platform elem) (pkg.meta.badPlatforms or []);
 }
diff --git a/nixpkgs/lib/modules.nix b/nixpkgs/lib/modules.nix
index d3f10944e708..99b9a8a31eac 100644
--- a/nixpkgs/lib/modules.nix
+++ b/nixpkgs/lib/modules.nix
@@ -23,6 +23,7 @@ let
     isAttrs
     isBool
     isFunction
+    isList
     isString
     length
     mapAttrs
@@ -37,7 +38,7 @@ let
     setAttrByPath
     toList
     types
-    warn
+    warnIf
     ;
   inherit (lib.options)
     isOption
@@ -127,7 +128,7 @@ rec {
         let collected = collectModules
           (specialArgs.modulesPath or "")
           (modules ++ [ internalModule ])
-          ({ inherit lib options config; } // specialArgs);
+          ({ inherit lib options config specialArgs; } // specialArgs);
         in mergeModules prefix (reverseList collected);
 
       options = merged.matchedOptions;
@@ -188,6 +189,9 @@ rec {
       loadModule = args: fallbackFile: fallbackKey: m:
         if isFunction m || isAttrs m then
           unifyModuleSyntax fallbackFile fallbackKey (applyIfFunction fallbackKey m args)
+        else if isList m then
+          let defs = [{ file = fallbackFile; value = m; }]; in
+          throw "Module imports can't be nested lists. Perhaps you meant to remove one level of lists? Definitions: ${showDefs defs}"
         else unifyModuleSyntax (toString m) (toString m) (applyIfFunction (toString m) (import m) args);
 
       /*
@@ -295,13 +299,11 @@ rec {
       # a module will resolve strictly the attributes used as argument but
       # not their values.  The values are forwarding the result of the
       # evaluation of the option.
-      requiredArgs = builtins.attrNames (lib.functionArgs f);
       context = name: ''while evaluating the module argument `${name}' in "${key}":'';
-      extraArgs = builtins.listToAttrs (map (name: {
-        inherit name;
-        value = builtins.addErrorContext (context name)
-          (args.${name} or config._module.args.${name});
-      }) requiredArgs);
+      extraArgs = builtins.mapAttrs (name: _:
+        builtins.addErrorContext (context name)
+          (args.${name} or config._module.args.${name})
+      ) (lib.functionArgs f);
 
       # Note: we append in the opposite order such that we can add an error
       # context on the explicited arguments of "args" too. This update
@@ -516,8 +518,8 @@ rec {
       value = if opt ? apply then opt.apply res.mergedValue else res.mergedValue;
 
       warnDeprecation =
-        if opt.type.deprecationMessage == null then id
-        else warn "The type `types.${opt.type.name}' of option `${showOption loc}' defined in ${showFiles opt.declarations} is deprecated. ${opt.type.deprecationMessage}";
+        warnIf (opt.type.deprecationMessage != null)
+          "The type `types.${opt.type.name}' of option `${showOption loc}' defined in ${showFiles opt.declarations} is deprecated. ${opt.type.deprecationMessage}";
 
     in warnDeprecation opt //
       { value = builtins.addErrorContext "while evaluating the option `${showOption loc}':" value;
diff --git a/nixpkgs/lib/strings.nix b/nixpkgs/lib/strings.nix
index 5010d9159cb8..49fa0196a0b2 100644
--- a/nixpkgs/lib/strings.nix
+++ b/nixpkgs/lib/strings.nix
@@ -606,7 +606,7 @@ rec {
      This function will fail if the input string is longer than the
      requested length.
 
-     Type: fixedWidthString :: int -> string -> string
+     Type: fixedWidthString :: int -> string -> string -> string
 
      Example:
        fixedWidthString 5 "0" (toString 15)
@@ -644,8 +644,8 @@ rec {
   floatToString = float: let
     result = toString float;
     precise = float == fromJSON result;
-  in if precise then result
-    else lib.warn "Imprecise conversion from float to string ${result}" result;
+  in lib.warnIf (!precise) "Imprecise conversion from float to string ${result}"
+    result;
 
   /* Check whether a value can be coerced to a string */
   isCoercibleToString = x:
@@ -659,7 +659,7 @@ rec {
      Example:
        isStorePath "/nix/store/d945ibfx9x185xf04b890y4f9g3cbb63-python-2.7.11/bin/python"
        => false
-       isStorePath "/nix/store/d945ibfx9x185xf04b890y4f9g3cbb63-python-2.7.11/"
+       isStorePath "/nix/store/d945ibfx9x185xf04b890y4f9g3cbb63-python-2.7.11"
        => true
        isStorePath pkgs.python
        => true
@@ -667,7 +667,7 @@ rec {
        => false
   */
   isStorePath = x:
-    if isCoercibleToString x then
+    if !(isList x) && isCoercibleToString x then
       let str = toString x; in
       substring 0 1 str == "/"
       && dirOf str == storeDir
diff --git a/nixpkgs/lib/systems/default.nix b/nixpkgs/lib/systems/default.nix
index 21b00374da47..70ec98b03c16 100644
--- a/nixpkgs/lib/systems/default.nix
+++ b/nixpkgs/lib/systems/default.nix
@@ -41,6 +41,19 @@ rec {
         else if final.isNetBSD              then "nblibc"
         # TODO(@Ericson2314) think more about other operating systems
         else                                     "native/impure";
+      # Choose what linker we wish to use by default. Someday we might also
+      # choose the C compiler, runtime library, C++ standard library, etc. in
+      # this way, nice and orthogonally, and deprecate `useLLVM`. But due to
+      # the monolithic GCC build we cannot actually make those choices
+      # independently, so we are just doing `linker` and keeping `useLLVM` for
+      # now.
+      linker =
+        /**/ if final.useLLVM or false      then "lld"
+        else if final.isDarwin              then "cctools"
+        # "bfd" and "gold" both come from GNU binutils. The existance of Gold
+        # is why we use the more obscure "bfd" and not "binutils" for this
+        # choice.
+        else                                     "bfd";
       extensions = {
         sharedLibrary =
           /**/ if final.isDarwin  then ".dylib"
@@ -118,7 +131,7 @@ rec {
         else null;
       # The canonical name for this attribute is darwinSdkVersion, but some
       # platforms define the old name "sdkVer".
-      darwinSdkVersion = final.sdkVer or "10.12";
+      darwinSdkVersion = final.sdkVer or (if final.isAarch64 then "11.0" else "10.12");
       darwinMinVersion = final.darwinSdkVersion;
       darwinMinVersionVariable =
         if final.isMacOS then "MACOSX_DEPLOYMENT_TARGET"
diff --git a/nixpkgs/lib/systems/doubles.nix b/nixpkgs/lib/systems/doubles.nix
index 6f638be585b1..c6d90ba9850d 100644
--- a/nixpkgs/lib/systems/doubles.nix
+++ b/nixpkgs/lib/systems/doubles.nix
@@ -96,5 +96,5 @@ in {
 
   embedded      = filterDoubles predicates.isNone;
 
-  mesaPlatforms = ["i686-linux" "x86_64-linux" "x86_64-darwin" "armv5tel-linux" "armv6l-linux" "armv7l-linux" "armv7a-linux" "aarch64-linux" "powerpc64-linux" "powerpc64le-linux"];
+  mesaPlatforms = ["i686-linux" "x86_64-linux" "x86_64-darwin" "armv5tel-linux" "armv6l-linux" "armv7l-linux" "armv7a-linux" "aarch64-linux" "powerpc64-linux" "powerpc64le-linux" "aarch64-darwin"];
 }
diff --git a/nixpkgs/lib/systems/examples.nix b/nixpkgs/lib/systems/examples.nix
index 9c0013c39778..6a8f4e091aae 100644
--- a/nixpkgs/lib/systems/examples.nix
+++ b/nixpkgs/lib/systems/examples.nix
@@ -70,6 +70,15 @@ rec {
     useAndroidPrebuilt = true;
   };
 
+  aarch64-android = {
+    config = "aarch64-unknown-linux-android";
+    sdkVer = "30";
+    ndkVer = "21";
+    libc = "bionic";
+    useAndroidPrebuilt = false;
+    useLLVM = true;
+  };
+
   scaleway-c1 = armv7l-hf-multiplatform // platforms.scaleway-c1;
 
   pogoplug4 = {
@@ -231,6 +240,12 @@ rec {
     useiOSPrebuilt = true;
   };
 
+  aarch64-darwin = {
+    config = "aarch64-apple-darwin";
+    xcodePlatform = "MacOSX";
+    platform = {};
+  };
+
   #
   # Windows
   #
diff --git a/nixpkgs/lib/systems/parse.nix b/nixpkgs/lib/systems/parse.nix
index a06ac0d11f74..2b789fd8ecb3 100644
--- a/nixpkgs/lib/systems/parse.nix
+++ b/nixpkgs/lib/systems/parse.nix
@@ -121,15 +121,28 @@ rec {
     js       = { bits = 32; significantByte = littleEndian; family = "js"; };
   };
 
-  # Determine where two CPUs are compatible with each other. That is,
-  # can we run code built for system b on system a? For that to
-  # happen, then the set of all possible possible programs that system
-  # b accepts must be a subset of the set of all programs that system
-  # a accepts. This compatibility relation forms a category where each
-  # CPU is an object and each arrow from a to b represents
-  # compatibility. CPUs with multiple modes of Endianness are
-  # isomorphic while all CPUs are endomorphic because any program
-  # built for a CPU can run on that CPU.
+  # GNU build systems assume that older NetBSD architectures are using a.out.
+  gnuNetBSDDefaultExecFormat = cpu:
+    if (cpu.family == "x86" && cpu.bits == 32) ||
+       (cpu.family == "arm" && cpu.bits == 32) ||
+       (cpu.family == "sparc" && cpu.bits == 32)
+    then execFormats.aout
+    else execFormats.elf;
+
+  # Determine when two CPUs are compatible with each other. That is,
+  # can code built for system B run on system A? For that to happen,
+  # the programs that system B accepts must be a subset of the
+  # programs that system A accepts.
+  #
+  # We have the following properties of the compatibility relation,
+  # which must be preserved when adding compatibility information for
+  # additional CPUs.
+  # - (reflexivity)
+  #   Every CPU is compatible with itself.
+  # - (transitivity)
+  #   If A is compatible with B and B is compatible with C then A is compatible with C.
+  # - (compatible under multiple endianness)
+  #   CPUs with multiple modes of endianness are pairwise compatible.
   isCompatible = a: b: with cpuTypes; lib.any lib.id [
     # x86
     (b == i386 && isCompatible a i486)
@@ -271,7 +284,7 @@ rec {
 
   kernels = with execFormats; with kernelFamilies; setTypes types.openKernel {
     # TODO(@Ericson2314): Don't want to mass-rebuild yet to keeping 'darwin' as
-    # the nnormalized name for macOS.
+    # the normalized name for macOS.
     macos    = { execFormat = macho;   families = { inherit darwin; }; name = "darwin"; };
     ios      = { execFormat = macho;   families = { inherit darwin; }; };
     freebsd  = { execFormat = elf;     families = { inherit bsd; }; };
@@ -458,8 +471,12 @@ rec {
     else "${cpu.name}-${kernel.name}";
 
   tripleFromSystem = { cpu, vendor, kernel, abi, ... } @ sys: assert isSystem sys; let
+    optExecFormat =
+      lib.optionalString (kernel.name == "netbsd" &&
+                          gnuNetBSDDefaultExecFormat cpu != kernel.execFormat)
+        kernel.execFormat.name;
     optAbi = lib.optionalString (abi != abis.unknown) "-${abi.name}";
-  in "${cpu.name}-${vendor.name}-${kernel.name}${optAbi}";
+  in "${cpu.name}-${vendor.name}-${kernel.name}${optExecFormat}${optAbi}";
 
   ################################################################################
 
diff --git a/nixpkgs/lib/systems/platforms.nix b/nixpkgs/lib/systems/platforms.nix
index f46e9c826a5c..92285346f754 100644
--- a/nixpkgs/lib/systems/platforms.nix
+++ b/nixpkgs/lib/systems/platforms.nix
@@ -375,6 +375,13 @@ rec {
     };
   };
 
+  apple-m1 = {
+    gcc = {
+      arch = "armv8.3-a+crypto+sha2+aes+crc+fp16+lse+simd+ras+rdm+rcpc";
+      cpu = "apple-a13";
+    };
+  };
+
   ##
   ## MIPS
   ##
@@ -474,11 +481,11 @@ rec {
   riscv-multiplatform = {
     linux-kernel = {
       name = "riscv-multiplatform";
-      target = "vmlinux";
+      target = "Image";
       autoModules = true;
       baseConfig = "defconfig";
+      DTB = true;
       extraConfig = ''
-        FTRACE n
         SERIAL_OF_PLATFORM y
       '';
     };
@@ -495,7 +502,10 @@ rec {
         else if lib.versionOlder version "6" then sheevaplug
         else if lib.versionOlder version "7" then raspberrypi
         else armv7l-hf-multiplatform
-    else if platform.isAarch64 then aarch64-multiplatform
+
+    else if platform.isAarch64 then
+      if platform.isDarwin then apple-m1
+      else aarch64-multiplatform
 
     else if platform.isRiscV then riscv-multiplatform
 
diff --git a/nixpkgs/lib/tests/modules.sh b/nixpkgs/lib/tests/modules.sh
index 2eddeec07b1a..2e57c2f8e2a1 100755
--- a/nixpkgs/lib/tests/modules.sh
+++ b/nixpkgs/lib/tests/modules.sh
@@ -175,6 +175,9 @@ checkConfigOutput "true" config.submodule.config ./declare-submoduleWith-noshort
 ## submoduleWith should merge all modules in one swoop
 checkConfigOutput "true" config.submodule.inner ./declare-submoduleWith-modules.nix
 checkConfigOutput "true" config.submodule.outer ./declare-submoduleWith-modules.nix
+# Should also be able to evaluate the type name (which evaluates freeformType,
+# which evaluates all the modules defined by the type)
+checkConfigOutput "submodule" options.submodule.type.description ./declare-submoduleWith-modules.nix
 
 ## Paths should be allowed as values and work as expected
 checkConfigOutput "true" config.submodule.enable ./declare-submoduleWith-path.nix
diff --git a/nixpkgs/lib/tests/modules/declare-submoduleWith-modules.nix b/nixpkgs/lib/tests/modules/declare-submoduleWith-modules.nix
index 4736ab41751b..a8b82d176881 100644
--- a/nixpkgs/lib/tests/modules/declare-submoduleWith-modules.nix
+++ b/nixpkgs/lib/tests/modules/declare-submoduleWith-modules.nix
@@ -8,9 +8,6 @@
             default = false;
           };
         }
-        {
-          outer = true;
-        }
       ];
     };
     default = {};
@@ -25,6 +22,7 @@
     })
     {
       inner = true;
+      outer = true;
     }
   ];
 }
diff --git a/nixpkgs/lib/trivial.nix b/nixpkgs/lib/trivial.nix
index be6d0115f5b8..e1581f1e91d6 100644
--- a/nixpkgs/lib/trivial.nix
+++ b/nixpkgs/lib/trivial.nix
@@ -171,7 +171,7 @@ rec {
      On each release the first letter is bumped and a new animal is chosen
      starting with that new letter.
   */
-  codeName = "Okapi";
+  codeName = "Porcupine";
 
   /* Returns the current nixpkgs version suffix as string. */
   versionSuffix =
@@ -297,12 +297,15 @@ rec {
   # Usage:
   # {
   #   foo = lib.warn "foo is deprecated" oldFoo;
+  #   bar = lib.warnIf (bar == "") "Empty bar is deprecated" bar;
   # }
   #
   # TODO: figure out a clever way to integrate location information from
   # something like __unsafeGetAttrPos.
 
   warn = msg: builtins.trace "warning: ${msg}";
+  warnIf = cond: msg: if cond then warn msg else id;
+
   info = msg: builtins.trace "INFO: ${msg}";
 
   showWarnings = warnings: res: lib.fold (w: x: warn w x) res warnings;
diff --git a/nixpkgs/lib/types.nix b/nixpkgs/lib/types.nix
index d0a8e96149d7..f47a1f92de72 100644
--- a/nixpkgs/lib/types.nix
+++ b/nixpkgs/lib/types.nix
@@ -147,9 +147,13 @@ rec {
     , # The deprecation message to display when this type is used by an option
       # If null, the type isn't deprecated
       deprecationMessage ? null
+    , # The types that occur in the definition of this type. This is used to
+      # issue deprecation warnings recursively. Can also be used to reuse
+      # nested types
+      nestedTypes ? {}
     }:
     { _type = "option-type";
-      inherit name check merge emptyValue getSubOptions getSubModules substSubModules typeMerge functor deprecationMessage;
+      inherit name check merge emptyValue getSubOptions getSubModules substSubModules typeMerge functor deprecationMessage nestedTypes;
       description = if description == null then name else description;
     };
 
@@ -256,14 +260,14 @@ rec {
         };
         u8 = unsign 8 256;
         u16 = unsign 16 65536;
-        # the biggest int a 64-bit Nix accepts is 2^63 - 1 (9223372036854775808), for a 32-bit Nix it is 2^31 - 1 (2147483647)
-        # the smallest int a 64-bit Nix accepts is -2^63 (-9223372036854775807), for a 32-bit Nix it is -2^31 (-2147483648)
-        # u32 = unsign 32 4294967296;
+        # the biggest int Nix accepts is 2^63 - 1 (9223372036854775808)
+        # the smallest int Nix accepts is -2^63 (-9223372036854775807)
+        u32 = unsign 32 4294967296;
         # u64 = unsign 64 18446744073709551616;
 
         s8 = sign 8 256;
         s16 = sign 16 65536;
-        # s32 = sign 32 4294967296;
+        s32 = sign 32 4294967296;
       };
 
     # Alias of u16 for a port number
@@ -337,7 +341,7 @@ rec {
     };
 
     shellPackage = package // {
-      check = x: (package.check x) && (hasAttr "shellPath" x);
+      check = x: isDerivation x && hasAttr "shellPath" x;
     };
 
     path = mkOptionType {
@@ -365,6 +369,7 @@ rec {
       getSubModules = elemType.getSubModules;
       substSubModules = m: listOf (elemType.substSubModules m);
       functor = (defaultFunctor name) // { wrapped = elemType; };
+      nestedTypes.elemType = elemType;
     };
 
     nonEmptyListOf = elemType:
@@ -389,6 +394,7 @@ rec {
       getSubModules = elemType.getSubModules;
       substSubModules = m: attrsOf (elemType.substSubModules m);
       functor = (defaultFunctor name) // { wrapped = elemType; };
+      nestedTypes.elemType = elemType;
     };
 
     # A version of attrsOf that's lazy in its values at the expense of
@@ -413,6 +419,7 @@ rec {
       getSubModules = elemType.getSubModules;
       substSubModules = m: lazyAttrsOf (elemType.substSubModules m);
       functor = (defaultFunctor name) // { wrapped = elemType; };
+      nestedTypes.elemType = elemType;
     };
 
     # TODO: drop this in the future:
@@ -421,6 +428,7 @@ rec {
       deprecationMessage = "Mixing lists with attribute values is no longer"
         + " possible; please use `types.attrsOf` instead. See"
         + " https://github.com/NixOS/nixpkgs/issues/1800 for the motivation.";
+      nestedTypes.elemType = elemType;
     };
 
     # Value of given type but with no merging (i.e. `uniq list`s are not concatenated).
@@ -433,6 +441,7 @@ rec {
       getSubModules = elemType.getSubModules;
       substSubModules = m: uniq (elemType.substSubModules m);
       functor = (defaultFunctor name) // { wrapped = elemType; };
+      nestedTypes.elemType = elemType;
     };
 
     # Null or value of ...
@@ -451,6 +460,7 @@ rec {
       getSubModules = elemType.getSubModules;
       substSubModules = m: nullOr (elemType.substSubModules m);
       functor = (defaultFunctor name) // { wrapped = elemType; };
+      nestedTypes.elemType = elemType;
     };
 
     functionTo = elemType: mkOptionType {
@@ -535,6 +545,9 @@ rec {
         substSubModules = m: submoduleWith (attrs // {
           modules = m;
         });
+        nestedTypes = lib.optionalAttrs (freeformType != null) {
+          freeformType = freeformType;
+        };
         functor = defaultFunctor name // {
           type = types.submoduleWith;
           payload = {
@@ -596,6 +609,8 @@ rec {
            then functor.type mt1 mt2
            else null;
       functor = (defaultFunctor name) // { wrapped = [ t1 t2 ]; };
+      nestedTypes.left = t1;
+      nestedTypes.right = t2;
     };
 
     # Any of the types in the given list
@@ -627,6 +642,8 @@ rec {
         substSubModules = m: coercedTo coercedType coerceFunc (finalType.substSubModules m);
         typeMerge = t1: t2: null;
         functor = (defaultFunctor name) // { wrapped = finalType; };
+        nestedTypes.coercedType = coercedType;
+        nestedTypes.finalType = finalType;
       };
 
     # Obsolete alternative to configOf.  It takes its option