diff --git a/addons/misra.py b/addons/misra.py
index 5fd5876b8..e2b9a4e98 100755
--- a/addons/misra.py
+++ b/addons/misra.py
@@ -420,9 +420,23 @@ def misra_4_1(rawTokens):
 
 
 def misra_5_1(data):
-    for token in data.tokenlist:
-        if token.isName and len(token.str) > 31:
-            reportError(token, 5, 1)
+    scopeVars = {}
+    for var in data.variables:
+        if var.isArgument:
+            continue
+        if var.nameToken.scope not in scopeVars:
+            scopeVars[var.nameToken.scope] = []
+        scopeVars[var.nameToken.scope].append(var)
+    for scope in scopeVars:
+        for i, variable1 in enumerate(scopeVars[scope]):
+            for variable2 in scopeVars[scope][i + 1:]:
+                if (variable1.isExtern and variable2.isExtern and
+                    variable1.nameToken.str[:31] == variable2.nameToken.str[:31] and
+                        variable1.Id != variable2.Id):
+                    if int(variable1.nameToken.linenr) > int(variable2.nameToken.linenr):
+                        reportError(variable1.nameToken, 5, 1)
+                    else:
+                        reportError(variable2.nameToken, 5, 1)
 
 def misra_5_2(data):
     scopeVars = {}
@@ -444,6 +458,8 @@ def misra_5_2(data):
             for variable2 in scopeVars[scope]["varlist"][i + 1:]:
                 if variable1.isArgument and variable2.isArgument:
                     continue
+                if variable1.isExtern and variable2.isExtern:
+                    continue
                 if (variable1.nameToken.str[:31] == variable2.nameToken.str[:31] and
                         variable1.Id != variable2.Id):
                     if int(variable1.nameToken.linenr) > int(variable2.nameToken.linenr):
@@ -466,6 +482,8 @@ def misra_5_2(data):
                     else:
                         reportError(scopename2.bodyStart, 5, 2)
 
+
+
 def misra_5_3(data):
     enum = []
     scopeVars = {}
diff --git a/addons/test/misra-test.c b/addons/test/misra-test.c
index 134ff188f..b5952ab6e 100644
--- a/addons/test/misra-test.c
+++ b/addons/test/misra-test.c
@@ -14,14 +14,17 @@ typedef unsigned long long u64;
 
 //// 3.1
 
-extern int n01_var_hides_var____________________________________________63x;
-static int n01_var_hides_var____________________________________________63y;//5.2
-static int n02_function_hides_var_______________________________________63x;
-void n02_function_hides_var_______________________________________63y(void) {}//5.2
+extern int misra_5_1_extern_var_hides_var_x;
+extern int misra_5_1_extern_var_hides_var_y; //5.1
+
+extern int misra_5_2_var_hides_var______31x;
+static int misra_5_2_var_hides_var______31y;//5.2
+static int misra_5_2_function_hides_var_31x;
+void misra_5_2_function_hides_var_31y(void) {}//5.2
 void foo(void) 
 {
   int i;
-  switch(f1()) 
+  switch(misra_5_2_func1()) //16.4 16.6
   {
     case 1: 
     {
@@ -29,35 +32,28 @@ void foo(void)
       {
         for(i = 0; i < 10; i++) 
         {
-          if(f3()) 
+          if(misra_5_2_func3()) //14.4
           {
-            int
-            n03_var_hides_var____________________________________________63x;
-            int
-            n03_var_hides_var____________________________________________63y;//5.2
+            int misra_5_2_var_hides_var_1____31x;
+            int misra_5_2_var_hides_var_1____31y;//5.2
           }
         }
-      } while(f2());
+      } while(misra_5_2_func2()); //14.4
     } 
   }
 }
 
-union n06_field_hides_field________________________________________63x {
-int n04_field_hides_field________________________________________63x;
-int n04_field_hides_field________________________________________63y;//5.2
+union misra_5_2_field_hides_field__63x { //19.2
+int misra_5_2_field_hides_field__31x;
+int misra_5_2_field_hides_field__31y;//5.2
 };
-struct n06_field_hides_field________________________________________63y { //5.2
-int n05_field_hides_field________________________________________63x;
-int n05_field_hides_field________________________________________63y;//5.2
+struct misra_5_2_field_hides_field__63y { //5.2
+int misra_5_2_field_hides_field1_31x;
+int misra_5_2_field_hides_field1_31y;//5.2
 };
 const char *s41_1 = "\x41g"; // 4.1
 const char *s41_2 = "\x41\x42";
 
-void misra_5_1() {
-  int a123456789012345678901234567890; // no-warning
-  int a1234567890123456789012345678901; // 5.1 5.2
-}
-
 extern int misra_5_3_var_hides_var______31x;
 void misra_5_3_var_hides_function_31x (void) {}
 enum misra_5_3_Enum {
@@ -68,18 +64,18 @@ void misra_5_3_func1(void)
   int misra_5_3_var_hides_var______31y; //5.3
   int misra_5_3_var_hides_function_31y; //5.3
   int misra_5_3_var_hidesenumconst_31y; //5.3
-  switch(misra_5_3_func2()) 
+  switch(misra_5_3_func2()) //16.4 16.6
   {
     case 1:
     {
       do 
       {
         int misra_5_3_var_hides_var_1____31x;
-        if(misra_5_3_func3())
+        if(misra_5_3_func3()) //14.4
         {
           int misra_5_3_var_hides_var_1____31y = 1; //5.3
         }
-      } while(misra_5_3_func2());
+      } while(misra_5_3_func2()); //14.4
     }
   }
 }
@@ -105,17 +101,17 @@ int x;
 };
 void misra_5_5_func1() 
 {
-  switch(misra_5_5_func2()) 
+  switch(misra_5_5_func2()) //16.4 16.6
   {
     case 1:
     {
       do 
       {
-        if(misra_5_5_func3())
+        if(misra_5_5_func3()) //14.4
         {
           int misra_5_5_hides_macro________31y; //5.5
         }
-      } while(misra_5_5_func2());
+      } while(misra_5_5_func2()); //14.4
     }
   }
 }