Fix #903 (false positive: buffer access out of bounds)

http://sourceforge.net/apps/trac/cppcheck/ticket/903

lib/checkbufferoverrun.cpp

@@ -668,6 +668,9 @@ void CheckBufferOverrun::checkGlobalAndLocalVariable()
             continue;
         }
 
+        if (varid == 0)
+            continue;
+
         Token sizeTok;
         sizeTok.str(type);
         int total_size = size * _tokenizer->sizeOfType(&sizeTok);

test/testbufferoverrun.cpp

@@ -296,6 +296,18 @@ private:
                   "}\n");
             ASSERT_EQUALS("[test.cpp:6]: (error) Buffer access out-of-bounds\n", errout.str());
         }
+
+        {
+            check("typedef struct g g2[3];\n"
+                  "void foo(char *a)\n"
+                  "{\n"
+                  "  for (int i = 0; i < 4; i++)\n"
+                  "  {\n"
+                  "    a[i]=0;\n"
+                  "  }\n"
+                  "}\n");
+            ASSERT_EQUALS("", errout.str());
+        }
     }