diff --git a/build_all.sh b/build_all.sh
new file mode 100644
index 0000000000..701d7d2042
--- /dev/null
+++ b/build_all.sh
@@ -0,0 +1,31 @@
+#! /bin/sh
+
+# build development version of the compiler; can be rerun safely
+
+set -u # error on undefined variables
+set -e # exit on first error
+
+echo_run(){
+  echo "\n$@"
+  "$@"
+}
+
+[ -d csources ] || echo_run git clone --depth 1 https://github.com/nim-lang/csources.git
+
+nim_csources=bin/nim_csources
+build_nim_csources(){
+  ## avoid changing dir in case of failure
+  (
+    echo_run cd csources
+    echo_run sh build.sh
+  )
+  # keep $nim_csources in case needed to investigate bootstrap issues
+  # without having to rebuild from csources
+  echo_run cp bin/nim $nim_csources
+}
+
+[ -f $nim_csources ] || echo_run build_nim_csources
+
+echo_run bin/nim c koch
+echo_run ./koch boot -d:release
+echo_run ./koch tools # Compile Nimble and other tools.
diff --git a/compiler/options.nim b/compiler/options.nim
index ff3e70800b..ef2b6023a6 100644
--- a/compiler/options.nim
+++ b/compiler/options.nim
@@ -482,7 +482,7 @@ include packagehandling
 
 proc getOsCacheDir(): string =
   when defined(posix):
-    result = getHomeDir() / ".cache"
+    result = string getEnv("XDG_CACHE_HOME", getHomeDir() / ".cache")
   else:
     result = getHomeDir() / genSubDir
 
diff --git a/doc/manual.rst b/doc/manual.rst
index 6ce72e2e1d..d60d58fe7a 100644
--- a/doc/manual.rst
+++ b/doc/manual.rst
@@ -1611,7 +1611,8 @@ A ``distinct`` type is new type derived from a `base type`:idx: that is
 incompatible with its base type. In particular, it is an essential property
 of a distinct type that it **does not** imply a subtype relation between it
 and its base type. Explicit type conversions from a distinct type to its
-base type and vice versa are allowed.
+base type and vice versa are allowed. See also ``distinctBase`` to get the
+reverse operation.
 
 
 Modelling currencies
diff --git a/doc/nimc.rst b/doc/nimc.rst
index 277c88ec11..fca5b273cf 100644
--- a/doc/nimc.rst
+++ b/doc/nimc.rst
@@ -159,7 +159,8 @@ Generated C code directory
 The generated files that Nim produces all go into a subdirectory called
 ``nimcache``. Its full path is
 
-- ``~/.cache/$projectname(_r|_d)`` on Posix
+- ``$XDG_CACHE_HOME/$projectname(_r|_d)`` or ``~/.cache/$projectname(_r|_d)``
+  on Posix
 - ``$HOME/nimcache/$projectname(_r|_d)`` on Windows.
 
 The ``_r`` suffix is used for release builds, ``_d`` is for debug builds.
diff --git a/lib/pure/collections/sequtils.nim b/lib/pure/collections/sequtils.nim
index 8f81fe4f50..99ce91979d 100644
--- a/lib/pure/collections/sequtils.nim
+++ b/lib/pure/collections/sequtils.nim
@@ -676,8 +676,8 @@ template mapIt*(s, op: untyped): untyped =
       var it{.inject.}: type(items(s));
       op))
   var result: seq[outType]
-  evalOnce(t, s)
-  when compiles(t.len):
+  when compiles(s.len):
+    evalOnce(t, s)
     var i = 0
     result = newSeq[outType](t.len)
     for it {.inject.} in t:
@@ -685,7 +685,7 @@ template mapIt*(s, op: untyped): untyped =
       i += 1
   else:
     result = @[]
-    for it {.inject.} in t:
+    for it {.inject.} in s:
       result.add(op)
   result
 
@@ -1071,5 +1071,10 @@ when isMainModule:
       proc foo(x: openArray[int]): seq[int] = x.mapIt(it + 1)
       doAssert foo([1,2,3]) == @[2,3,4]
 
+  block: # mapIt with invalid RHS for `let` (#8566)
+    type X = enum
+      A, B
+    doAssert mapIt(X, $it) == @["A", "B"]
+
   when not defined(testing):
     echo "Finished doc tests"
diff --git a/lib/pure/httpclient.nim b/lib/pure/httpclient.nim
index 8b4fb0f8c1..72de727184 100644
--- a/lib/pure/httpclient.nim
+++ b/lib/pure/httpclient.nim
@@ -807,6 +807,7 @@ type
     lastProgressReport: float
     when SocketType is AsyncSocket:
       bodyStream: FutureStream[string]
+      parseBodyFut: Future[void]
     else:
       bodyStream: Stream
     getBody: bool ## When `false`, the body is never read in requestAux.
@@ -1066,10 +1067,14 @@ proc parseResponse(client: HttpClient | AsyncHttpClient,
   if getBody:
     when client is HttpClient:
       client.bodyStream = newStringStream()
+      result.bodyStream = client.bodyStream
+      parseBody(client, result.headers, result.version)
     else:
       client.bodyStream = newFutureStream[string]("parseResponse")
-    await parseBody(client, result.headers, result.version)
-    result.bodyStream = client.bodyStream
+      result.bodyStream = client.bodyStream
+      assert(client.parseBodyFut.isNil or client.parseBodyFut.finished)
+      client.parseBodyFut = parseBody(client, result.headers, result.version)
+        # do not wait here for the body request to complete
 
 proc newConnection(client: HttpClient | AsyncHttpClient,
                    url: Uri) {.multisync.} =
@@ -1159,6 +1164,12 @@ proc requestAux(client: HttpClient | AsyncHttpClient, url: string,
   # Helper that actually makes the request. Does not handle redirects.
   let requestUrl = parseUri(url)
 
+  when client is AsyncHttpClient:
+    if not client.parseBodyFut.isNil:
+      # let the current operation finish before making another request
+      await client.parseBodyFut
+      client.parseBodyFut = nil
+
   await newConnection(client, requestUrl)
 
   let effectiveHeaders = client.headers.override(headers)
diff --git a/lib/pure/sugar.nim b/lib/pure/sugar.nim
index 258b40191a..8ded552d9d 100644
--- a/lib/pure/sugar.nim
+++ b/lib/pure/sugar.nim
@@ -198,3 +198,41 @@ macro dump*(x: typed): untyped =
   let r = quote do:
     debugEcho `s`, " = ", `x`
   return r
+
+# TODO: consider exporting this in macros.nim
+proc freshIdentNodes(ast: NimNode): NimNode =
+  # Replace NimIdent and NimSym by a fresh ident node
+  # see also https://github.com/nim-lang/Nim/pull/8531#issuecomment-410436458
+  proc inspect(node: NimNode): NimNode =
+    case node.kind:
+    of nnkIdent, nnkSym:
+      result = ident($node)
+    of nnkEmpty, nnkLiterals:
+      result = node
+    else:
+      result = node.kind.newTree()
+      for child in node:
+        result.add inspect(child)
+  result = inspect(ast)
+
+macro distinctBase*(T: typedesc): untyped =
+  ## reverses ``type T = distinct A``; works recursively.
+  runnableExamples:
+    type T = distinct int
+    doAssert distinctBase(T) is int
+    doAssert: not compiles(distinctBase(int))
+    type T2 = distinct T
+    doAssert distinctBase(T2) is int
+
+  let typeNode = getTypeImpl(T)
+  expectKind(typeNode, nnkBracketExpr)
+  if typeNode[0].typeKind != ntyTypeDesc:
+    error "expected typeDesc, got " & $typeNode[0]
+  var typeSym = typeNode[1]
+  typeSym = getTypeImpl(typeSym)
+  if typeSym.typeKind != ntyDistinct:
+    error "type is not distinct"
+  typeSym = typeSym[0]
+  while typeSym.typeKind == ntyDistinct:
+    typeSym = getTypeImpl(typeSym)[0]
+  typeSym.freshIdentNodes
diff --git a/lib/system/channels.nim b/lib/system/channels.nim
index 254b87dfcc..14d3a30055 100644
--- a/lib/system/channels.nim
+++ b/lib/system/channels.nim
@@ -233,7 +233,7 @@ proc send*[TMsg](c: var Channel[TMsg], msg: TMsg) {.inline.} =
 proc trySend*[TMsg](c: var Channel[TMsg], msg: TMsg): bool {.inline.} =
   ## Tries to send a message to a thread. `msg` is deeply copied. Doesn't block.
   ## Returns `false` if the message was not sent because number of pending items
-  ## in the cannel exceeded `maxItems`.
+  ## in the channel exceeded `maxItems`.
   sendImpl(cast[PRawChannel](addr c), cast[PNimType](getTypeInfo(msg)), unsafeAddr(msg), true)
 
 proc llRecv(q: PRawChannel, res: pointer, typ: PNimType) =
diff --git a/readme.md b/readme.md
index bdc7c7549e..e4fb52bd01 100644
--- a/readme.md
+++ b/readme.md
@@ -50,24 +50,33 @@ Next, to build from source you will need:
     other distros as well). 
 
 Then, if you are on a \*nix system or Windows, the following steps should compile
-Nim from source using ``gcc``, ``git`` and the ``koch`` build tool (in the place
-of ``sh build.sh`` you should substitute ``build.bat`` on x86 Windows or
-``build64.bat`` on x86_64 Windows):
+Nim from source using ``gcc``, ``git`` and the ``koch`` build tool.
 
 **Note: The following commands are for the development version of the compiler.**
 For most users, installing the latest stable version is enough. Check out
 the installation instructions on the website to do so: https://nim-lang.org/install.html.
 
 ```
+# step 1:
 git clone https://github.com/nim-lang/Nim.git
 cd Nim
+
+# step 2 (posix) clones `csources.git`, bootstraps Nim compiler and compiles tools
+sh build_all.sh
+
+# step 2 (windows)
 git clone --depth 1 https://github.com/nim-lang/csources.git
+
 cd csources
-sh build.sh
-cd ../
-bin/nim c koch
-./koch boot -d:release
-./koch tools # Compile Nimble and other tools.
+# requires `gcc` in your PATH, see also https://nim-lang.org/install_windows.html
+build.bat # x86 Windows
+build64.bat # x86_64 Windows
+cd ..
+
+bin\nim c koch
+koch boot -d:release
+koch tools # Compile Nimble and other tools
+# end of step 2 (windows)
 ```
 
 Finally, once you have finished the build steps (on Windows, Mac or Linux) you
diff --git a/tests/generics/t6137.nim b/tests/generics/t6137.nim
new file mode 100644
index 0000000000..639675f35d
--- /dev/null
+++ b/tests/generics/t6137.nim
@@ -0,0 +1,29 @@
+discard """
+  action: "reject"
+  line: 29
+  errormsg: "\'vectFunc\' doesn't have a concrete type, due to unspecified generic parameters."
+"""
+
+type
+  # simple vector of declared fixed length
+  vector[N : static[int]] = array[0..N-1, float]
+
+proc `*`[T](x: float, a: vector[T]): vector[T] =
+  # multiplication by scalar
+  for ii in 0..high(a):
+    result[ii] = a[ii]*x
+
+let
+  # define a vector of length 3
+  x: vector[3] = [1.0, 3.0, 5.0]
+
+proc vectFunc[T](x: vector[T]): vector[T] {.procvar.} =
+  # Define a vector function
+  result = 2.0*x
+
+proc passVectFunction[T](g: proc(x: vector[T]): vector[T], x: vector[T]): vector[T] =
+  # pass a vector function as input in another procedure
+  result = g(x)
+
+let
+  xNew = passVectFunction(vectFunc,x)
diff --git a/tests/generics/t7141.nim b/tests/generics/t7141.nim
new file mode 100644
index 0000000000..8a128d828a
--- /dev/null
+++ b/tests/generics/t7141.nim
@@ -0,0 +1,10 @@
+discard """
+  action: "reject"
+  line: 7
+  errormsg: "cannot instantiate: \'T\'"
+"""
+
+proc foo[T](x: T) =
+  discard
+
+var fun = if true: foo else: foo
diff --git a/tests/metatype/ttypeselectors.nim b/tests/metatype/ttypeselectors.nim
index 2a2455adb5..eb857271dd 100644
--- a/tests/metatype/ttypeselectors.nim
+++ b/tests/metatype/ttypeselectors.nim
@@ -99,3 +99,15 @@ echo sizeof(a)
 echo sizeof(b)
 echo sizeof(c)
 
+# This is the same example but using a proc instead of a macro
+# Instead of type mismatch for macro, proc just failed with internal error: getTypeDescAux(tyNone)
+# https://github.com/nim-lang/Nim/issues/7231
+
+proc getBase2*(bits: static[int]): typedesc =
+  if bits == 128:
+    result = newTree(nnkBracketExpr, ident("MpUintBase"), ident("uint64"))
+  else:
+    result = newTree(nnkBracketExpr, ident("MpUintBase"), ident("uint32"))
+
+type
+  MpUint2*[bits: static[int]] = getbase2(bits)
diff --git a/tests/stdlib/tsugar.nim b/tests/stdlib/tsugar.nim
new file mode 100644
index 0000000000..a870bf6fed
--- /dev/null
+++ b/tests/stdlib/tsugar.nim
@@ -0,0 +1,29 @@
+discard """
+  file: "tsugar.nim"
+  output: ""
+"""
+import sugar
+import macros
+
+block distinctBase:
+  block:
+    type
+      Foo[T] = distinct seq[T]
+    var a: Foo[int]
+    doAssert a.type.distinctBase is seq[int]
+
+  block:
+    # simplified from https://github.com/nim-lang/Nim/pull/8531#issuecomment-410436458
+    macro uintImpl(bits: static[int]): untyped =
+      if bits >= 128:
+        let inner = getAST(uintImpl(bits div 2))
+        result = newTree(nnkBracketExpr, ident("UintImpl"), inner)
+      else:
+        result = ident("uint64")
+
+    type
+      BaseUint = UintImpl or SomeUnsignedInt
+      UintImpl[Baseuint] = object
+      Uint[bits: static[int]] = distinct uintImpl(bits)
+
+    doAssert Uint[128].distinctBase is UintImpl[uint64]