consider calling convention and iterator in getType for procs (#24181)

fixes #19010

`getType` for proc types generated an `nkProcTy` for iterator types
instead of `nkIteratorTy`, and didn't generate a calling convention
pragma unless it was in the proc AST. Iterator types now generate
`nkIteratorTy`, and a calling convention pragma is added if the calling
convention isn't `closure` or was explicitly provided.

compiler/vmdeps.nim

@@ -237,7 +237,7 @@ proc mapTypeToAstX(cache: IdentCache; t: PType; info: TLineInfo;
   of tySequence: result = mapTypeToBracket("seq", mSeq, t, info)
   of tyProc:
     if inst:
-      result = newNodeX(nkProcTy)
+      result = newNodeX(if tfIterator in t.flags: nkIteratorTy else: nkProcTy)
       var fp = newNodeX(nkFormalParams)
       if t.returnType == nil:
         fp.add newNodeI(nkEmpty, info)
@@ -246,8 +246,15 @@ proc mapTypeToAstX(cache: IdentCache; t: PType; info: TLineInfo;
       for i in FirstParamAt..<t.kidsLen:
         fp.add newIdentDefs(t.n[i], t[i])
       result.add fp
-      result.add if t.n[0].len > 0: t.n[0][pragmasEffects].copyTree
-                 else: newNodeI(nkEmpty, info)
+      var prag =
+        if t.n[0].len > 0:
+          t.n[0][pragmasEffects].copyTree
+        else:
+          newNodeI(nkEmpty, info)
+      if t.callConv != ccClosure or tfExplicitCallConv in t.flags:
+        if prag.kind == nkEmpty: prag = newNodeI(nkPragma, info)
+        prag.add newIdentNode(getIdent(cache, $t.callConv), info)
+      result.add prag
     else:
       result = mapTypeToBracket("proc", mNone, t, info)
   of tyOpenArray: result = mapTypeToBracket("openArray", mOpenArray, t, info)

tests/macros/tmacrotypes.nim

@@ -1,9 +1,9 @@
 discard """
-  nimout: '''intProc; ntyProc; proc[int, int, float]; proc (a: int; b: float): int
+  nimout: '''intProc; ntyProc; proc[int, int, float]; proc (a: int; b: float): int {.nimcall.}
 void; ntyVoid; void; void
 int; ntyInt; int; int
-proc (); ntyProc; proc[void]; proc ()
-voidProc; ntyProc; proc[void]; proc ()
+proc () {.nimcall.}; ntyProc; proc[void]; proc () {.nimcall.}
+voidProc; ntyProc; proc[void]; proc () {.nimcall.}
 listing fields for ObjType
 a: string
 b: int

tests/macros/tprocgettype.nim

@@ -0,0 +1,28 @@
+discard """
+  nimout: '''
+var x: proc () {.cdecl.} = foo
+var x: iterator (): int {.closure.} = bar
+'''
+"""
+
+# issue #19010
+
+import macros
+
+macro createVar(x: typed): untyped =
+  result = nnkVarSection.newTree:
+    newIdentDefs(ident"x", getTypeInst(x), copy(x))
+  
+  echo repr result
+
+block:
+  proc foo() {.cdecl.} = discard
+
+  createVar(foo)
+  x()
+
+block:
+  iterator bar(): int {.closure.} = discard
+
+  createVar(bar)
+  for a in x(): discard