Fix #12169 (False positive: wrong misra-config variable with accessing object in memory) (#5645)

Author: danmar

.github/workflows/CI-unixish.yml

@@ -424,6 +424,8 @@ jobs:
           ./cppcheck --error-exitcode=1 --inline-suppr --addon=threadsafety addons/test/threadsafety
           ./cppcheck --error-exitcode=1 --inline-suppr --addon=threadsafety --std=c++03 addons/test/threadsafety
           ./cppcheck --error-exitcode=1 --inline-suppr --addon=misra addons/test/misra/crash*.c
+          ./cppcheck --error-exitcode=1 --inline-suppr --addon=misra --enable=information addons/test/misra/config*.c
+
           ./cppcheck --addon=misra --enable=style --inline-suppr --enable=information --error-exitcode=1 addons/test/misra/misra-ctu-*-test.c
           pushd addons/test
           # We'll force C89 standard to enable an additional verification for

addons/misra.py

@@ -3315,6 +3315,10 @@ def misra_config(self, data):
                     continue
                 if isKeyword(tok.str) or isStdLibId(tok.str):
                     continue
+                if tok.astParent is None:
+                    continue
+                if tok.astParent.str == "." and tok.astParent.valueType:
+                    continue
                 self.report_config_error(tok, "Variable '%s' is unknown" % tok.str)
 
     def misra_17_6(self, rawTokens):

addons/test/misra/config1.c

@@ -0,0 +1,10 @@
+
+struct S {
+    uint32_t some[100];
+};
+
+void foo( void )
+{
+    if (((S *)0x8000)->some[0] != 0U) { }
+}
+