[lldb] Assert index is valid in DWARFDeclContext

[JDevlieghere]

Summary

Address my own comment from D153867.

[fdeazeve]

Thanks for doing this!

[fdeazeve]

lldb/source/Plugins/SymbolFile/DWARF/DWARFDeclContext.h

58

Note the difference in how you used () between the two asserts

[JDevlieghere]

lldb/source/Plugins/SymbolFile/DWARF/DWARFDeclContext.h

58

Yup, typo below. I put up the patch before my build finished :-)

lldb/source/Plugins/SymbolFile/DWARF/DWARFDeclContext.h

 //===-- DWARFDeclContext.h --------------------------------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLDB_SOURCE_PLUGINS_SYMBOLFILE_DWARF_DWARFDECLCONTEXT_H
 #define LLDB_SOURCE_PLUGINS_SYMBOLFILE_DWARF_DWARFDECLCONTEXT_H
 
-#include <string>
-#include <vector>
 #include "lldb/Utility/ConstString.h"
 #include "DWARFDefines.h"
 
+#include <cassert>
+#include <string>
+#include <vector>
+
 // DWARFDeclContext
 //
 // A class that represents a declaration context all the way down to a
 // DIE. This is useful when trying to find a DIE in one DWARF to a DIE
 // in another DWARF file.
 
 class DWARFDeclContext {
 public:
public:
   }
 
   bool operator==(const DWARFDeclContext &rhs) const;
   bool operator!=(const DWARFDeclContext &rhs) const { return !(*this == rhs); }
 
   uint32_t GetSize() const { return m_entries.size(); }
 
   Entry &operator[](uint32_t idx) {
-    // "idx" must be valid
+    assert(idx < m_entries.size() && "invalid index");
     return m_entries[idx];
   }
 
   const Entry &operator[](uint32_t idx) const {
-    // "idx" must be valid
+    assert(idx < m_entries.size() && "invalid index");
     return m_entries[idx];
   }
 
   const char *GetQualifiedName() const;
 
   // Same as GetQualifiedName, but the life time of the returned string will
   // be that of the LLDB session.
   lldb_private::ConstString GetQualifiedNameAsConstString() const {