[linters] Add an example of checking for an empty map in the argument of a method call

Reviewed By: ikenwoo

Differential Revision: D5678779

fbshipit-source-id: 90ecb0d

infer/tests/codetoanalyze/objcpp/linters-for-test-only/TestParamterLabelsChecks.mm

@@ -25,7 +25,7 @@ struct SomeStruct {
 
 SomeButton* buttonComponent(void);
 SomeButton* buttonComponent(void) {
-  // flagging passing empty struct
+  // flagging passing empty struct and map
   return [SomeButton newWithStruct:{} map:{} object:nil number:0];
 };
 

infer/tests/codetoanalyze/objcpp/linters-for-test-only/issues.exp

@@ -7,5 +7,6 @@ codetoanalyze/objcpp/linters-for-test-only/ReferenceTest.mm, ReferenceTest_newWi
 codetoanalyze/objcpp/linters-for-test-only/TestParamterLabelsChecks.mm, anotherButtonComponent, 34, TEST_PARAMETER_LABEL, []
 codetoanalyze/objcpp/linters-for-test-only/TestParamterLabelsChecks.mm, anotherButtonComponent, 34, TEST_PARAMETER_LABEL_REGEXP, []
 codetoanalyze/objcpp/linters-for-test-only/TestParamterLabelsChecks.mm, buttonComponent, 29, TEST_PARAMETER_LABEL, []
+codetoanalyze/objcpp/linters-for-test-only/TestParamterLabelsChecks.mm, buttonComponent, 29, TEST_PARAMETER_LABEL_EMPTY_MAP, []
 codetoanalyze/objcpp/linters-for-test-only/TestParamterLabelsChecks.mm, buttonComponent, 29, TEST_PARAMETER_LABEL_EMPTY_STRUCT, []
 codetoanalyze/objcpp/linters-for-test-only/TestParamterLabelsChecks.mm, buttonComponent, 29, TEST_PARAMETER_LABEL_REGEXP, []

infer/tests/codetoanalyze/objcpp/linters-for-test-only/linters_example.al

@@ -55,3 +55,27 @@ DEFINE-CHECKER TEST_PARAMETER_LABEL_EMPTY_STRUCT = {
       HOLDS-IN-NODE ObjCMessageExpr;
   SET message = "Do not pass empty struct to the parameter `newWithStruct` of method `new...`";
 };
+
+DEFINE-CHECKER TEST_PARAMETER_LABEL_EMPTY_MAP = {
+   //This means the node has no children.
+  LET constructor_with_no_parameters =
+    WHEN (FALSE HOLDS-EVERYWHERE-NEXT) HOLDS-IN-NODE CXXConstructExpr;
+
+  LET temp_expr =
+    WHEN (constructor_with_no_parameters HOLDS-EVERYWHERE-NEXT) HOLDS-IN-NODE CXXBindTemporaryExpr;
+
+   LET is_empty_map =
+    WHEN (temp_expr HOLDS-EVERYWHERE-NEXT) HOLDS-IN-NODE MaterializeTemporaryExpr;
+
+  LET method_has_parameter_type =
+        WHEN
+          HOLDS-NEXT WITH-TRANSITION ParameterName "map"
+            (is_empty_map)
+          HOLDS-IN-NODE ObjCMessageExpr;
+  SET report_when =
+      WHEN
+         method_has_parameter_type
+         AND call_method(REGEXP("^new.*:$"))
+      HOLDS-IN-NODE ObjCMessageExpr;
+  SET message = "Do not pass empty map to the parameter `map` of method `new...`";
+};