fix nim-lang#13524 astToStr now works inside generics

compiler/semgnrc.nim

@@ -226,14 +226,7 @@ proc semGenericStmt(c: PContext, n: PNode,
     var mixinContext = false
     if s != nil:
       incl(s.flags, sfUsed)
-      # more robust/future proof than:
-      # mixinContext = s.magic in {mDefined, mDefinedInScope, mCompiles, mAstToStr}
-      if s.magic != mNone and s.typ != nil:
-        for i in 1..<s.typ.len:
-          if s.typ[i].kind == tyUntyped:
-            mixinContext = true
-            break
-
+      mixinContext = s.magic in {mDefined, mDefinedInScope, mCompiles, mAstToStr}
       let sc = symChoice(c, fn, s, if s.isMixedIn: scForceOpen else: scOpen)
       case s.kind
       of skMacro:
@@ -290,9 +283,6 @@ proc semGenericStmt(c: PContext, n: PNode,
     # is not exported and yet the generic 'threadProcWrapper' works correctly.
     let flags = if mixinContext: flags+{withinMixin} else: flags
     for i in first..<result.safeLen:
-      # instead, would be better to only set `withinMixin` for arguments of
-      # kind tyUntyped, eg `if s.typ[i].kind == tyUntyped:`, however, this
-      # currently doesn't work
       result[i] = semGenericStmt(c, result[i], flags, ctx)
   of nkCurlyExpr:
     result = newNodeI(nkCall, n.info)

lib/system.nim

@@ -1629,7 +1629,7 @@ else:
       result[i+1] = y[i]
 
 
-proc astToStr*(x: untyped): string {.magic: "AstToStr", noSideEffect.}
+proc astToStr*[T](x: T): string {.magic: "AstToStr", noSideEffect.}
   ## Converts the AST of `x` into a string representation. This is very useful
   ## for debugging.