hasCustomPragma/getCustomPragmaVal: small fix (#7650)

* fix hasCustomPragma/getCustomPragmaVal for types without pragma

* fix pragma on pointer test

* removed trailing spaces

lib/core/macros.nim

@@ -1288,7 +1288,11 @@ proc customPragmaNode(n: NimNode): NimNode =
     typ = n.getTypeInst()
 
   if typ.typeKind == ntyTypeDesc:
-    return typ[1].getImpl()[0][1]
+    let impl = typ[1].getImpl()
+    if impl[0].kind == nnkPragmaExpr:
+      return impl[0][1]
+    else:
+      return impl[0] # handle types which don't have macro at all
 
   if n.kind == nnkSym: # either an variable or a proc
     let impl = n.getImpl()

tests/pragmas/tcustom_pragma.nim

@@ -51,6 +51,9 @@ block: # A bit more advanced case
 
   static: assert(hasCustomPragma(myproc, alternativeKey))
 
+  const hasFieldCustomPragma = s.field.hasCustomPragma(defaultValue)
+  static: assert(hasFieldCustomPragma == false)
+
   # pragma on an object
   static:
     assert Subfield.hasCustomPragma(defaultValue)
@@ -71,6 +74,8 @@ block: # ref types
     MyFile {.defaultValue: "closed".} = ref object
       path {.defaultValue: "invalid".}: string
 
+    TypeWithoutPragma = object
+
   var s = NodeRef()
 
   const
@@ -91,7 +96,7 @@ block: # ref types
 
   var ptrS = NodePtr(nil)
   const
-    ptrRightSerKey = getCustomPragmaVal(s.right, serializationKey)
+    ptrRightSerKey = getCustomPragmaVal(ptrS.right, serializationKey)
   static:
     assert ptrRightSerKey == "r"
 
@@ -103,6 +108,9 @@ block: # ref types
     assert fileDefVal == "closed"
     assert filePathDefVal == "invalid"
 
+  static:
+    assert TypeWithoutPragma.hasCustomPragma(defaultValue) == false
+
 block:
   type
     VariantKind = enum