Add model validation for constructor summary models

Author: owen-mc

java/ql/lib/semmle/code/java/dataflow/ExternalFlow.qll

@@ -367,12 +367,24 @@ module ModelValidation {
     )
   }
 
+  string getIncorrectConstructorSummaryOutput() {
+    exists(string namespace, string type, string name, string output |
+      summaryModel(namespace, type, _, name, _, _, _, output, _, _, _)
+    |
+      type = name and
+      output.matches("ReturnValue%") and
+      result =
+        "Constructor model for " + namespace + "." + type +
+          " should use `Argument[this]` in the output, not `ReturnValue`."
+    )
+  }
+
   /** Holds if some row in a MaD flow model appears to contain typos. */
   query predicate invalidModelRow(string msg) {
     msg =
       [
         getInvalidModelSignature(), getInvalidModelInput(), getInvalidModelOutput(),
-        KindVal::getInvalidModelKind()
+        getIncorrectConstructorSummaryOutput(), KindVal::getInvalidModelKind()
       ]
   }
 }

java/ql/test/library-tests/dataflow/external-models/validatemodels.expected

@@ -0,0 +1,9 @@
+| Constructor model for java.net.URI should use `Argument[this]` in the output, not `ReturnValue`. |
+| Constructor model for java.util.zip.ZipEntry should use `Argument[this]` in the output, not `ReturnValue`. |
+| Constructor model for org.apache.hc.core5.http.io.entity.BasicHttpEntity should use `Argument[this]` in the output, not `ReturnValue`. |
+| Constructor model for org.apache.hc.core5.http.io.entity.BufferedHttpEntity should use `Argument[this]` in the output, not `ReturnValue`. |
+| Constructor model for org.apache.hc.core5.http.io.entity.HttpEntityWrapper should use `Argument[this]` in the output, not `ReturnValue`. |
+| Constructor model for org.apache.hc.core5.http.io.entity.InputStreamEntity should use `Argument[this]` in the output, not `ReturnValue`. |
+| Constructor model for org.apache.http.entity.BufferedHttpEntity should use `Argument[this]` in the output, not `ReturnValue`. |
+| Constructor model for org.apache.http.entity.HttpEntityWrapper should use `Argument[this]` in the output, not `ReturnValue`. |
+| Constructor model for org.apache.http.entity.InputStreamEntity should use `Argument[this]` in the output, not `ReturnValue`. |