fixes #23564; hasCustomPragma skips alises types (#24994)

fixes #23564

perhaps handle generic aliases (tyGenericInst for aliases types) if
needed

Author: ringabout

compiler/vm.nim

@@ -1873,7 +1873,7 @@ proc rawExecute(c: PCtx, start: int, tos: PStackFrame): TFullReg =
           regs[ra].node = opMapTypeInstToAst(c.cache, regs[rb].node.sym.typ, c.debug[pc], c.idgen)
         else:
           stackTrace(c, tos, pc, "node has no type")
-      else:
+      of 3:
         # getTypeImpl opcode:
         ensureKind(rkNode)
         if regs[rb].kind == rkNode and regs[rb].node.typ != nil:
@@ -1882,6 +1882,15 @@ proc rawExecute(c: PCtx, start: int, tos: PStackFrame): TFullReg =
           regs[ra].node = opMapTypeImplToAst(c.cache, regs[rb].node.sym.typ, c.debug[pc], c.idgen)
         else:
           stackTrace(c, tos, pc, "node has no type")
+      else:
+        # getTypeInstSkipAlias opcode:
+        ensureKind(rkNode)
+        if regs[rb].kind == rkNode and regs[rb].node.typ != nil:
+          regs[ra].node = opMapTypeInstToAst(c.cache, regs[rb].node.typ, c.debug[pc], c.idgen, skipAlias = true)
+        elif regs[rb].kind == rkNode and regs[rb].node.kind == nkSym and regs[rb].node.sym.typ != nil:
+          regs[ra].node = opMapTypeInstToAst(c.cache, regs[rb].node.sym.typ, c.debug[pc], c.idgen, skipAlias = true)
+        else:
+          stackTrace(c, tos, pc, "node has no type")
     of opcNGetSize:
       decodeBImm(rkInt)
       let n = regs[rb].node

compiler/vmdeps.nim

@@ -42,7 +42,7 @@ proc atomicTypeX(s: PSym; info: TLineInfo): PNode =
   result.info = info
 
 proc mapTypeToAstX(cache: IdentCache; t: PType; info: TLineInfo; idgen: IdGenerator;
-                   inst=false; allowRecursionX=false): PNode
+                   inst=false; allowRecursionX=false; skipAlias = false): PNode
 
 proc mapTypeToBracketX(cache: IdentCache; name: string; m: TMagic; t: PType; info: TLineInfo;
                        idgen: IdGenerator;
@@ -70,7 +70,7 @@ proc objectNode(cache: IdentCache; n: PNode; idgen: IdGenerator): PNode =
 
 proc mapTypeToAstX(cache: IdentCache; t: PType; info: TLineInfo;
                    idgen: IdGenerator;
-                   inst=false; allowRecursionX=false): PNode =
+                   inst=false; allowRecursionX=false; skipAlias = false): PNode =
   var allowRecursion = allowRecursionX
   template atomicType(name, m): untyped = atomicTypeX(cache, name, m, t, info, idgen)
   template atomicType(s): untyped = atomicTypeX(s, info)
@@ -91,7 +91,8 @@ proc mapTypeToAstX(cache: IdentCache; t: PType; info: TLineInfo;
     id
   template newIdentDefs(s): untyped = newIdentDefs(s, s.typ)
 
-  if inst and not allowRecursion and t.sym != nil:
+  if inst and not allowRecursion and t.sym != nil and
+      not (skipAlias and t.kind == tyAlias):
     # getTypeInst behavior: return symbol
     return atomicType(t.sym)
 
@@ -124,7 +125,7 @@ proc mapTypeToAstX(cache: IdentCache; t: PType; info: TLineInfo;
     if t.base != nil:
       result = newNodeIT(nkBracketExpr, if t.n.isNil: info else: t.n.info, t)
       result.add atomicType("typeDesc", mTypeDesc)
-      result.add mapTypeToAst(t.base, info)
+      result.add mapTypeToAstX(cache, t.base, info, idgen, inst, skipAlias = skipAlias)
     else:
       result = atomicType("typeDesc", mTypeDesc)
   of tyGenericInvocation:
@@ -153,7 +154,7 @@ proc mapTypeToAstX(cache: IdentCache; t: PType; info: TLineInfo;
     else:
       result = mapTypeToAst(t.typeBodyImpl, info)
   of tyAlias:
-    result = mapTypeToAstX(cache, t.skipModifier, info, idgen, inst, allowRecursion)
+    result = mapTypeToAstX(cache, t.skipModifier, info, idgen, inst, allowRecursion, skipAlias = skipAlias)
   of tyOrdinal:
     result = mapTypeToAst(t.skipModifier, info)
   of tyDistinct:
@@ -325,8 +326,9 @@ proc opMapTypeToAst*(cache: IdentCache; t: PType; info: TLineInfo; idgen: IdGene
 
 # the "Inst" version includes generic parameters in the resulting type tree
 # and also tries to look like the corresponding Nim type declaration
-proc opMapTypeInstToAst*(cache: IdentCache; t: PType; info: TLineInfo; idgen: IdGenerator): PNode =
-  result = mapTypeToAstX(cache, t, info, idgen, inst=true, allowRecursionX=false)
+proc opMapTypeInstToAst*(cache: IdentCache; t: PType; info: TLineInfo; idgen: IdGenerator; skipAlias = false): PNode =
+  # skipAlias: skips aliases and typedesc
+  result = mapTypeToAstX(cache, t, info, idgen, inst=true, allowRecursionX=false, skipAlias = skipAlias)
 
 # the "Impl" version includes generic parameters in the resulting type tree
 # and also tries to look like the corresponding Nim type implementation

compiler/vmgen.nim

@@ -1337,7 +1337,8 @@ proc genMagic(c: PCtx; n: PNode; dest: var TDest; flags: TGenFlags = {}, m: TMag
       of "getType": 0
       of "typeKind": 1
       of "getTypeInst": 2
-      else: 3  # "getTypeImpl"
+      of "getTypeImpl": 3  # "getTypeImpl"
+      else: 4 # getTypeInstSkipAlias
     c.gABC(n, opcNGetType, dest, tmp, rc)
     c.freeTemp(tmp)
     #genUnaryABC(c, n, dest, opcNGetType)

lib/core/macros.nim

@@ -1575,11 +1575,14 @@ proc extractTypeImpl(n: NimNode): NimNode =
     result = n[2]
   else: error("Invalid node to retrieve type implementation of: " & $n.kind)
 
+
+proc getTypeInstSkipAlias(n: NimNode): NimNode {.magic: "NGetType", noSideEffect.}
+
 proc customPragmaNode(n: NimNode): NimNode =
   result = nil
   expectKind(n, {nnkSym, nnkDotExpr, nnkBracketExpr, nnkTypeOfExpr, nnkType, nnkCheckedFieldExpr})
-  let
-    typ = n.getTypeInst()
+
+  let typ = n.getTypeInstSkipAlias()
 
   if typ.kind == nnkBracketExpr and typ.len > 1 and typ[1].kind == nnkProcTy:
     return typ[1][1]

tests/pragmas/tcustom_pragma.nim

@@ -538,3 +538,14 @@ block: # https://forum.nim-lang.org/t/12522, backticks
   type Test = object
     field {.`mypragma`.}: int
   doAssert Test().field.hasCustomPragma(mypragma)
+
+
+block:
+  template p {.pragma.}
+
+  func foo[T0](v: T0): bool =
+    type T = T0
+    T.hasCustomPragma(p)
+
+  type X {.p.} = object
+  doAssert foo(X())