support for static params in the user defined type classes

compiler/ast.nim

@@ -399,6 +399,7 @@ const
   tyPureObject* = tyTuple
   GcTypeKinds* = {tyRef, tySequence, tyString}
   tyError* = tyProxy # as an errornous node should match everything
+  tyUnknown* = tyFromExpr
 
   tyUnknownTypes* = {tyError, tyFromExpr}
 

compiler/semcall.nim

@@ -277,16 +277,14 @@ proc semResolvedCall(c: PContext, n: PNode, x: TCandidate): PNode =
   styleCheckUse(n.sons[0].info, finalCallee)
   if finalCallee.ast == nil:
     internalError(n.info, "calleeSym.ast is nil") # XXX: remove this check!
-  if finalCallee.ast.sons[genericParamsPos].kind != nkEmpty:
+  if x.hasFauxMatch:
-    # a generic proc!
-    if not x.proxyMatch:
-      finalCallee = generateInstance(c, x.calleeSym, x.bindings, n.info)
-    else:
     result = x.call
     result.sons[0] = newSymNode(finalCallee, result.sons[0].info)
-      result.typ = finalCallee.typ.sons[0]
+    if containsGenericType(result.typ) or x.fauxMatch == tyUnknown:
-      if containsGenericType(result.typ): result.typ = errorType(c)
+      result.typ = newTypeS(x.fauxMatch, c)
     return
+  if finalCallee.ast.sons[genericParamsPos].kind != nkEmpty:
+    finalCallee = generateInstance(c, x.calleeSym, x.bindings, n.info)
   result = x.call
   instGenericConvertersSons(c, result, x)
   result.sons[0] = newSymNode(finalCallee, result.sons[0].info)

compiler/semstmts.nim

@@ -1262,10 +1262,14 @@ proc semStmtList(c: PContext, n: PNode, flags: TExprFlags): PNode =
       return
     else:
       n.sons[i] = semExpr(c, n.sons[i])
-      if c.inTypeClass > 0 and n[i].typ != nil and n[i].typ.kind == tyBool:
+      if c.inTypeClass > 0 and n[i].typ != nil:
+        case n[i].typ.kind
+        of tyBool:
           let verdict = semConstExpr(c, n[i])
           if verdict.intVal == 0:
             localError(result.info, "type class predicate failed")
+        of tyUnknown: continue
+        else: discard
       if n.sons[i].typ == enforceVoidContext or usesResult(n.sons[i]):
         voidContext = true
         n.typ = enforceVoidContext

compiler/semtypes.nim

@@ -781,9 +781,11 @@ proc liftParamType(c: PContext, procKind: TSymKind, genericParams: PNode,
   of tyGenericBody:
     result = newTypeS(tyGenericInvokation, c)
     result.rawAddSon(paramType)
+      
     for i in 0 .. paramType.sonsLen - 2:
-      result.rawAddSon newTypeS(tyAnything, c)
+      let dummyType = if paramType.sons[i].kind == tyStatic: tyUnknown
-      # result.rawAddSon(copyType(paramType.sons[i], getCurrOwner(), true))
+                      else: tyAnything
+      result.rawAddSon newTypeS(dummyType, c)
       
     if paramType.lastSon.kind == tyUserTypeClass:
       result.kind = tyUserTypeClassInst

compiler/sigmatch.nim

@@ -39,7 +39,9 @@ type
     bindings*: TIdTable      # maps types to types
     baseTypeMatch: bool      # needed for conversions from T to openarray[T]
                              # for example
-    proxyMatch*: bool        # to prevent instantiations
+    fauxMatch*: TTypeKind    # the match was successful only due to the use
+                             # of error or wildcard (unknown) types.
+                             # this is used to prevent instantiations.
     genericConverter*: bool  # true if a generic converter needs to
                              # be instantiated
     coerceDistincts*: bool   # this is an explicit coercion that can strip away
@@ -66,6 +68,8 @@ const
     
 proc markUsed*(info: TLineInfo, s: PSym)
 
+template hasFauxMatch*(c: TCandidate): bool = c.fauxMatch != tyNone
+
 proc initCandidateAux(ctx: PContext,
                       c: var TCandidate, callee: PType) {.inline.} =
   c.c = ctx
@@ -465,9 +469,23 @@ proc matchUserTypeClass*(c: PContext, m: var TCandidate,
       var
         typeParamName = ff.base.sons[i-1].sym.name
         typ = ff.sons[i]
-        param = newSym(skType, typeParamName, body.sym, body.sym.info)
+        param: PSym
 
+      template paramSym(kind): expr =
+        newSym(kind, typeParamName, body.sym, body.sym.info)
+
+      case typ.kind
+      of tyStatic:
+        param = paramSym skConst
+        param.typ = typ.base
+        param.ast = typ.n
+      of tyUnknown:
+        param = paramSym skVar
+        param.typ = typ
+      else:
+        param = paramSym skType
         param.typ = makeTypeDesc(c, typ)
+      
       addDecl(c, param)
 
   for param in body.n[0]:
@@ -1067,7 +1085,7 @@ proc implicitConv(kind: TNodeKind, f: PType, arg: PNode, m: TCandidate,
                   c: PContext): PNode = 
   result = newNodeI(kind, arg.info)
   if containsGenericType(f):
-    if not m.proxyMatch:
+    if not m.hasFauxMatch:
       result.typ = getInstantiatedType(c, arg, m, f)
     else:
       result.typ = errorType(c)
@@ -1246,9 +1264,9 @@ proc paramTypesMatchAux(m: var TCandidate, f, argType: PType,
       result = implicitConv(nkHiddenStdConv, f, copyTree(arg), m, c)
   of isNone:
     # do not do this in ``typeRel`` as it then can't infere T in ``ref T``:
-    if a.kind == tyProxy:
+    if a.kind in {tyProxy, tyUnknown}:
       inc(m.genericMatches)
-      m.proxyMatch = true
+      m.fauxMatch = a.kind
       return copyTree(arg)
     result = userConvMatch(c, m, f, a, arg) 
     # check for a base type match, which supports varargs[T] without []

tests/metatype/tusertypeclasses.nim

@@ -1,5 +1,13 @@
 discard """
-  output: "Sortable\nSortable\nContainer"
+  output: '''Sortable
+Sortable
+Container
+true
+true
+false
+false
+false
+'''
 """
 
 import typetraits
@@ -41,3 +49,20 @@ proc y(x: TObj): int = 10
 proc testFoo(x: TFoo) = discard
 testFoo(TObj(x: 10))
 
+type
+  Matrix[Rows, Cols: static[int]; T] = generic M
+    M.M == Rows
+    M.N == Cols
+    M.T is T
+
+  MyMatrix[M, N: static[int]; T] = object
+    data: array[M*N, T]
+
+var x: MyMatrix[3, 3, int]
+
+echo x is Matrix
+echo x is Matrix[3, 3, int]
+echo x is Matrix[3, 3, float]
+echo x is Matrix[4, 3, int]
+echo x is Matrix[3, 4, int]
+