cppcheckdata: Fix crash on an empty union (#3326)

addons/cppcheckdata.py

@@ -404,7 +404,9 @@ class Scope:
         self.nestedIn = IdMap[self.nestedInId]
         self.function = IdMap[self.functionId]
         for v in self.varlistId:
-            self.varlist.append(IdMap[v])
+            value = IdMap.get(v)
+            if value:
+                self.varlist.append(value)
 
 
 class Function:

addons/test/misra/misra-test.c

@@ -41,6 +41,16 @@
 #include <tgmath.h> // 21.11
 #include <fenv.h>
 
+// Check that the addon doesn't crash
+typedef struct {
+  union { // 19.2
+    struct {
+      unsigned a : 2;
+      unsigned : 14;
+    };
+    uint16_t value;
+  };
+} STRUCT_BITS;
 
 typedef unsigned char      u8;
 typedef unsigned short     u16;