Quick Fix in Dynamic Dispatch

Previously if there was a contract def that only had impls defined such that dynamic dispatch was supported over a subset of args, you'd run into an internal compiler error (NPE). That's fixed.

src/java/com/claro/intermediate_representation/statements/StmtListNode.java

@@ -42,8 +42,7 @@ public void assertExpectedExprTypes(ScopedHeap scopedHeap) throws ClaroTypeExcep
         // TODO(steving) Find some way to make this assertion in the CUP parsing phase itself. Once we start
         //  implementing better error messages with line numbers etc, I get a feeling that
         //  throwing this manner of error here will make it hard to get line numbers right.
-        throw new ClaroParserException(
-            "Unreachable statements following a return/break stmt are not allowed." + curr.getChildren().get(0));
+        throw new ClaroParserException("Unreachable statements following a return/break stmt are not allowed.");
       }
 
       Stmt currStmt = ((Stmt) curr.getChildren().get(0));

src/java/com/claro/intermediate_representation/statements/contracts/ContractDefinitionStmt.java

@@ -679,8 +679,11 @@ private StringBuilder generateDynamicDispatchHelperForContractProcedure(String p
                       .requiredContextualOutputTypeAssertionTypeParamNames
                       .contains(this.typeParamNames.get(n))
                   ||
-                  this.contractProceduresSupportingDynamicDispatchOverArgsWhenGenericReturnTypeInferenceRequired
-                      .get(procedureName).values().stream().anyMatch(i -> n == i)) {
+                  Optional.ofNullable(
+                          this.contractProceduresSupportingDynamicDispatchOverArgsWhenGenericReturnTypeInferenceRequired
+                              .get(procedureName))
+                      .map(m -> m.values().stream().anyMatch(i -> n == i))
+                      .orElse(false)) {
                 return String.format("$%s_vtableKey", this.typeParamNames.get(n));
               }
               Type onlyConcreteTypeForCurrTypeParam =