* fix nim-lang#9855, fix nim-lang#9855, new: getTypeId, fix genericHead

compiler/ast.nim

@@ -976,8 +976,9 @@ const
     tyPointer,
     tyOpenArray, tyString, tyCString, tyInt..tyInt64, tyFloat..tyFloat128,
     tyUInt..tyUInt64}
-  IntegralTypes* = {tyBool, tyChar, tyEnum, tyInt..tyInt64,
+  NumberLikeTypes* = {tyBool, tyChar, tyEnum, tyInt..tyInt64,
     tyFloat..tyFloat128, tyUInt..tyUInt64}
+  IntegralTypes* = NumberLikeTypes + {tyEnum} # weird name because it contains tyFloat
   ConstantDataTypes*: TTypeKinds = {tyArray, tySet,
                                     tyTuple, tySequence}
   NilableTypes*: TTypeKinds = {tyPointer, tyCString, tyRef, tyPtr,

compiler/semexprs.nim

@@ -396,12 +396,21 @@ proc isOpImpl(c: PContext, n: PNode, flags: TExprFlags): PNode =
     else:
       res = false
   else:
-    maybeLiftType(t2, c, n.info)
+    if t1.skipTypes({tyAlias}).kind != tyGenericBody:
+      maybeLiftType(t2, c, n.info)
+    else:
+      #[
+      for this case:
+      type Foo = object[T]
+      Foo is Foo
+      ]#
+      discard
     var m = newCandidate(c, t2)
     if efExplain in flags:
       m.diagnostics = @[]
       m.diagnosticsEnabled = true
     res = typeRel(m, t2, t1) >= isSubtype # isNone
+    # `res = sameType(t1, t2)` would be wrong, eg for `int is (int|float)`
 
   result = newIntNode(nkIntLit, ord(res))
   result.typ = n.typ

compiler/semmagic.nim

@@ -121,6 +121,11 @@ proc uninstantiate(t: PType): PType =
     of tyCompositeTypeClass: uninstantiate t[1]
     else: t
 
+proc getTypeDescNode(typ: PType, sym: PSym, info: TLineInfo): PNode =
+  var resType = newType(tyTypeDesc, sym)
+  rawAddSon(resType, typ)
+  result = toNode(resType, info)
+
 proc evalTypeTrait(c: PContext; traitCall: PNode, operand: PType, context: PSym): PNode =
   const skippedTypes = {tyTypeDesc, tyAlias, tySink}
   let trait = traitCall[0]
@@ -160,14 +165,22 @@ proc evalTypeTrait(c: PContext; traitCall: PNode, operand: PType, context: PSym)
     result = newIntNode(nkIntLit, operand.len - ord(operand.kind==tyProc))
     result.typ = newType(tyInt, context)
     result.info = traitCall.info
+  of "getTypeid":
+    var arg = operand
+    if arg.kind in NumberLikeTypes:
+      # needed otherwise we could get different ids, see tests
+      arg = getSysType(c.graph, traitCall[1].info, arg.kind)
+    result = newIntNode(nkIntLit, arg.id)
+      # `id` better than cast[int](arg) so that it's reproducible across compiles
+    result.typ = getSysType(c.graph, traitCall[1].info, tyInt)
+    result.info = traitCall.info
   of "genericHead":
-    var res = uninstantiate(operand)
-    if res == operand and res.kind notin tyMagicGenerics:
-      localError(c.config, traitCall.info,
-        "genericHead expects a generic type. The given type was " &
-        typeToString(operand))
-      return newType(tyError, context).toNode(traitCall.info)
-    result = res.base.toNode(traitCall.info)
+    var arg = operand
+    if arg.kind == tyGenericInst:
+      result = getTypeDescNode(arg.base, operand.owner, traitCall.info)
+    else:
+      localError(c.config, traitCall.info, "expected generic instantiation, got: " & $(arg.kind, typeToString(operand)))
+      result = newType(tyError, context).toNode(traitCall.info)
   of "stripGenericParams":
     result = uninstantiate(operand).toNode(traitCall.info)
   of "supportsCopyMem":
@@ -185,9 +198,7 @@ proc evalTypeTrait(c: PContext; traitCall: PNode, operand: PType, context: PSym)
       while arg.kind == tyDistinct:
         arg = arg.base
         arg = arg.skipTypes(skippedTypes + {tyGenericInst})
-      var resType = newType(tyTypeDesc, operand.owner)
-      rawAddSon(resType, arg)
-      result = toNode(resType, traitCall.info)
+      result = getTypeDescNode(arg, operand.owner, traitCall.info)
     else:
       localError(c.config, traitCall.info,
         "distinctBase expects a distinct type as argument. The given type was " & typeToString(operand))

compiler/semtypes.nim

@@ -1383,7 +1383,7 @@ proc semGeneric(c: PContext, n: PNode, s: PSym, prev: PType): PType =
     return newOrPrevType(tyError, prev, c)
 
   var t = s.typ
-  if t.kind == tyCompositeTypeClass and t.base.kind == tyGenericBody:
+  if t.kind in {tyCompositeTypeClass, tyAlias} and t.base.kind == tyGenericBody:
     t = t.base
 
   result = newOrPrevType(tyGenericInvocation, prev, c)
@@ -1403,7 +1403,7 @@ proc semGeneric(c: PContext, n: PNode, s: PSym, prev: PType): PType =
   elif t.kind != tyGenericBody:
     # we likely got code of the form TypeA[TypeB] where TypeA is
     # not generic.
-    localError(c.config, n.info, errNoGenericParamsAllowedForX % s.name.s)
+    localError(c.config, n.info, errNoGenericParamsAllowedForX % $(s.name.s, t.kind))
     return newOrPrevType(tyError, prev, c)
   else:
     var m = newCandidate(c, t)
@@ -1454,7 +1454,7 @@ proc semGeneric(c: PContext, n: PNode, s: PSym, prev: PType): PType =
     recomputeFieldPositions(tx, tx.n, position)
 
 proc maybeAliasType(c: PContext; typeExpr, prev: PType): PType =
-  if typeExpr.kind in {tyObject, tyEnum, tyDistinct, tyForward} and prev != nil:
+  if typeExpr.kind in {tyObject, tyEnum, tyDistinct, tyForward, tyGenericBody} and prev != nil:
     result = newTypeS(tyAlias, c)
     result.rawAddSon typeExpr
     result.sym = prev.sym
@@ -1781,8 +1781,7 @@ proc semTypeNode(c: PContext, n: PNode, prev: PType): PType =
       else:
         assignType(prev, s.typ)
         # bugfix: keep the fresh id for aliases to integral types:
-        if s.typ.kind notin {tyBool, tyChar, tyInt..tyInt64, tyFloat..tyFloat128,
-                             tyUInt..tyUInt64}:
+        if s.typ.kind notin NumberLikeTypes:
           prev.id = s.typ.id
         result = prev
   of nkSym:

lib/pure/typetraits.nim

@@ -16,6 +16,16 @@ export system.`$` # for backward compatibility
 
 include "system/inclrtl"
 
+proc getTypeid*(t: typedesc): int {.magic: "TypeTrait", since: (1, 1).} =
+  ## returns a unique id representing a type; the id is stable across
+  ## recompilations of the same program, but may differ if the program source
+  ## changes.
+  runnableExamples:
+    type Foo[T] = object
+    type Foo2 = Foo
+    doAssert Foo[int].getTypeid == Foo2[type(1)].getTypeid
+    doAssert Foo[int].getTypeid != Foo[float].getTypeid
+
 proc name*(t: typedesc): string {.magic: "TypeTrait".}
   ## Returns the name of the given type.
   ##

tests/metatype/ttypetraits.nim

@@ -47,7 +47,7 @@ block: # typeToString
   doAssert MyInt.name3 == "MyInt{int}"
   doAssert (tuple[a: MyInt, b: float]).name3 == "tuple[a: MyInt{int}, b: float]"
   doAssert (tuple[a: C2b[MyInt, C4[cstring]], b: cint, c: float]).name3 ==
-    "tuple[a: C2b{C}[MyInt{int}, C4[cstring]], b: cint{int32}, c: float]"
+    "tuple[a: C[MyInt{int}, C4[cstring]], b: cint{int32}, c: float]"
 
 block distinctBase:
   block:
@@ -125,4 +125,47 @@ var x = CpuStorage[string]()
 static:
   doAssert(not string.supportsCopyMem)
   doAssert x.T is string          # true
-  doAssert x.raw_buffer is seq
+  doAssert x.raw_buffer is seq
+
+block:
+  const c1 = getTypeid(type(12))
+  const a1 = getTypeid(type(12))
+  const a2 = getTypeid(type(12))
+  let a3 = getTypeid(type(12))
+  doAssert a1 == a2
+    # we need to check that because nim uses different id's
+    # for different instances of tyInt (etc), so we make sure implementation of
+    # `getTypeid` is robust to that
+  doAssert a1 == a3
+  doAssert getTypeid(type(12.0)) != getTypeid(type(12))
+  doAssert getTypeid(type(12.0)) == getTypeid(float)
+
+  type Foo = object
+    x1: int
+
+  type FooT[T] = object
+    x1: int
+  type Foo2 = Foo
+  type FooT2 = FooT
+  doAssert Foo.getTypeid == Foo2.getTypeid
+  doAssert FooT2.getTypeid == FooT.getTypeid
+  doAssert FooT2[float].getTypeid == FooT[type(1.2)].getTypeid
+  doAssert FooT2[float].getTypeid != FooT[type(1)].getTypeid
+  doAssert Foo.x1.type.getTypeid == int.getTypeid
+
+block genericHead:
+  type Foo[T1,T2] = object
+    x1: T1
+    x2: T2
+  type FooInst = Foo[int, float]
+  type Foo2 = genericHead(FooInst)
+  doAssert Foo2 is Foo # issue #13066
+  type Foo2Inst = Foo2[int, float]
+  doAssert FooInst.default == Foo2Inst.default
+  doAssert FooInst.default.x2 == 0.0
+  doAssert Foo2Inst is FooInst
+  doAssert FooInst is Foo2Inst
+  doAssert compiles(genericHead(FooInst))
+  doAssert not compiles(genericHead(Foo))
+  type Bar = object
+  doAssert not compiles(genericHead(Bar))

tests/types/tisopr.nim

@@ -89,3 +89,23 @@ proc test[T](x: T) =
     echo "no"
 
 test(7)
+
+block:
+  # bug #13066
+  type Bar[T1,T2] = object
+  type Foo[T1,T2] = object
+  type Foo2 = Foo
+  doAssert Foo2 is Foo
+  doAssert Foo is Foo2
+  doAssert Foo is Foo
+  doAssert Foo2 is Foo2
+  doAssert Foo2 isnot Bar
+  doAssert Foo[int,float] is Foo2[int,float]
+
+  # other
+  doAssert Foo[int,float] isnot Foo2[float,float]
+  doAssert Foo[int,float] is Foo2
+  doAssert Foo[int,float|int] is Foo2
+  doAssert Foo2[int,float|int] is Foo
+  doAssert Foo2[int,float|int] isnot Bar
+  doAssert int is (int|float)