destructors: defensive programming against wrong generated destructor for string/seq

compiler/commands.nim

@@ -480,7 +480,7 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
     of "native", "gdb":
       incl(conf.globalOptions, optCDebug)
       conf.options = conf.options + {optLineDir} - {optEndb}
-      defineSymbol(conf.symbols, "nimTypeNames") # type names are used in gdb pretty printing
+      #defineSymbol(conf.symbols, "nimTypeNames") # type names are used in gdb pretty printing
       undefSymbol(conf.symbols, "endb")
     else:
       localError(conf, info, "expected endb|gdb but found " & arg)

compiler/semasgn.nim

@@ -309,6 +309,10 @@ proc liftBody(c: PContext; typ: PType; kind: TTypeAttachedOp;
   liftBodyAux(a, typ, body, newSymNode(dest).newDeref, newSymNode(src))
   # recursion is handled explicitly, do not register the type based operation
   # before 'liftBodyAux':
+  if c.config.selectedGC == gcDestructors and
+      typ.kind in {tySequence, tyString} and body.len == 0:
+    discard "do not cache it yet"
+  else:
     case kind
     of attachedAsgn: typ.assignment = result
     of attachedSink: typ.sink = result