fix sets of scoped imported enums (#13666)

compiler/ccgtypes.nim

@@ -880,7 +880,8 @@ proc getTypeDescAux(m: BModule, origTyp: PType, check: var IntSet): Rope =
           m.s[cfsTypes].add(recdesc)
         elif tfIncompleteStruct notin t.flags: addAbiCheck(m, t, result)
   of tySet:
-    result = $t.kind & '_' & getTypeName(m, t.lastSon, hashType t.lastSon)
+    # Don't use the imported name as it may be scoped: 'Foo::SomeKind'
+    result = $t.kind & '_' & t.lastSon.typeName & $t.lastSon.hashType
     m.typeCache[sig] = result
     if not isImportedType(t):
       let s = int(getSize(m.config, t))

tests/cpp/enum.hpp

@@ -0,0 +1,3 @@
+namespace namespaced {
+enum Enum { A, B, C };
+}

tests/cpp/tenum_set.nim

@@ -0,0 +1,9 @@
+discard """
+targets: "cpp"
+output: "{A, B, C}"
+"""
+
+type Enum {.importcpp: "namespaced::Enum", header: "enum.hpp".} = enum A, B, C
+
+var vals = {low(Enum) .. high(Enum)}
+echo vals