close #10734 add testcase (#16692)

* close #10734 add testcase

* fix

* fix

Author: ringabout

tests/errmsgs/t10734.nim

@@ -0,0 +1,19 @@
+discard """
+  cmd: "nim check $file"
+  errormsg: ""
+  nimout: '''
+t10734.nim(18, 1) Error: invalid indentation
+t10734.nim(18, 6) Error: invalid indentation
+t10734.nim(19, 7) Error: expression expected, but found '[EOF]'
+t10734.nim(17, 5) Error: 'proc' is not a concrete type; for a callback without parameters use 'proc()'
+t10734.nim(18, 6) Error: undeclared identifier: 'p'
+t10734.nim(18, 6) Error: 'p' cannot be assigned to
+t10734.nim(16, 3) Hint: 'T' is declared but not used [XDeclaredButNotUsed]
+'''
+"""
+
+type
+  T = object
+    a:
+proc p =
+  case