Rule 16.7: Use the essential type

Relational operations do not have boolean type in C, so we need to use
the essential type library to identify them.

Author: lcartey

c/misra/src/rules/RULE-16-7/SwitchExpressionBoolCondition.ql

@@ -13,8 +13,11 @@
 
 import cpp
 import codingstandards.c.misra
-import codingstandards.cpp.SwitchStatement
+import codingstandards.c.misra.EssentialTypes
 
-from BooleanSwitchStmt switch
-where not isExcluded(switch, Statements2Package::switchExpressionBoolConditionQuery())
-select switch, "The condition of this $@ statement has boolean type", switch, "switch"
+from SwitchStmt switch, Expr controllingExpr
+where
+  not isExcluded(switch, Statements2Package::switchExpressionBoolConditionQuery()) and
+  controllingExpr = switch.getControllingExpr() and
+  getEssentialTypeCategory(getEssentialType(controllingExpr)) = EssentiallyBooleanType()
+select controllingExpr, "The condition of this $@ statement has boolean type", switch, "switch"

c/misra/test/rules/RULE-16-7/SwitchExpressionBoolCondition.expected

@@ -0,0 +1,2 @@
+| test.c:16:11:16:17 | ... == ... | The condition of this $@ statement has boolean type | test.c:16:3:24:3 | switch (...) ...  | switch |
+| test.c:28:11:28:24 | ... == ... | The condition of this $@ statement has boolean type | test.c:28:3:36:3 | switch (...) ...  | switch |