switch s := s.(type) {
	default:
		panic("unreachable")

	case *ast.BadStmt, *ast.DeclStmt, *ast.EmptyStmt, *ast.SendStmt,
		*ast.IncDecStmt, *ast.AssignStmt, *ast.GoStmt, *ast.DeferStmt,
		*ast.RangeStmt:
		// no chance

	case *ast.LabeledStmt:
		return check.isTerminating(s.Stmt, s.Label.Name)

	case *ast.ExprStmt:

		}

		resp := rootIdent(asg.Lhs[0])
		if resp == nil {
			return true // could not find the http.Response in the assignment.
		}

		def, ok := stmts[1].(*ast.DeferStmt)
		if !ok {
			return true // the following statement is not a defer.
		}
		root := rootIdent(def.Call.Fun)
		if root == nil {
			return true // could not find the receiver of the defer call.
		}

		Walk(v, n.Chan)
		Walk(v, n.Value)

	case *IncDecStmt:
		Walk(v, n.X)

	case *AssignStmt:
		walkList(v, n.Lhs)
		walkList(v, n.Rhs)

	case *GoStmt:
		Walk(v, n.Call)

	case *DeferStmt:
		Walk(v, n.Call)

	case *ReturnStmt:
		walkList(v, n.Results)

	case *BranchStmt:
		if n.Label != nil {
			Walk(v, n.Label)
		}

	case *BlockStmt:
		walkList(v, n.List)