misra: Emit more accurate warnings for unused arguments in rule 2.7 (#3314)

Make the MISRA addon emit extra warnings for unused arguments placed in
lines other than the function definition. This makes it easier for the
user to find violations.

addons/misra.py

@@ -1136,9 +1136,19 @@ class MisraChecker:
                         if token.variable is not None and token.variable in func_param_list:
                             func_param_list.remove(token.variable)
                         token = token.next
-                    if len(func_param_list) > 0:
+                    # Emit a warning for each unused variable, but no more that one warning per line
-                        # At least one parameter has not been referenced in function body
+                    reported_linenrs = set()
-                        self.reportError(func.tokenDef, 2, 7)
+                    for func_param in func_param_list:
+                        if func_param.nameToken:
+                            linenr = func_param.nameToken
+                            if linenr not in reported_linenrs:
+                                self.reportError(func_param.nameToken, 2, 7)
+                                reported_linenrs.add(linenr)
+                        else:
+                            linenr = func.tokenDef.linenr
+                            if linenr not in reported_linenrs:
+                                self.reportError(func.tokenDef, 2, 7)
+                                reported_linenrs.add(linenr)
 
     def misra_3_1(self, rawTokens):
         for token in rawTokens:

addons/test/misra/misra-test.c

@@ -65,8 +65,21 @@ void misra_2_7_used_params (int *param1, int param2, int param3)
     *param1 = param2;
 }
 
-void misra_2_7_vararg(int a, ...) { (void)a; }
+void misra_2_7_a(int a,
-void misra_2_7_unnamed_arg(int) { } // 2.7 8.2
+                 int b, // 2.7
+                 int c,
+                 int d) // 2.7
+{
+    (void)a;
+    (void)c;
+}
+void misra_2_7_b(int a, int b, int c, // 2.7
+                 int d)               // 2.7
+{
+    (void)a;
+}
+void misra_2_7_c(int a, ...) { (void)a; }
+void misra_2_7_d(int) { } // 2.7 8.2
 
 void misra_3_2(int enable)
 {