feat(bug): Simple fix

Signed-off-by: Jaskeerat Singh Saluja <[email protected]>

packages/concerto-core/lib/introspect/modelfile.js

@@ -275,19 +275,19 @@ class ModelFile extends Decorated {
         // Validate all of the types in this model file.
         // Check if names of the declarations are unique.
         const uniqueNames = new Set();
-        this.declarations.forEach(
-            d => {
-                const fqn = d.getFullyQualifiedName();
-                if (!uniqueNames.has(fqn)) {
-                    uniqueNames.add(fqn);
-                } else {
-                    throw new IllegalModelException(
-                        `Duplicate class name ${fqn}`
-                    );
-                }
+        this.declarations.forEach(d => {
+            const fqn = d.getFullyQualifiedName();
+            const shortName = ModelUtil.getShortName(fqn);
+            if (uniqueNames.has(fqn)) {
+                throw new IllegalModelException(`Duplicate class name: ${fqn}`);
             }
-        );
-
+            if (this.importShortNames.has(shortName)) {
+                throw new IllegalModelException(
+                    `TypeName Conflict: The type '${shortName}' is being redefined, but it already exists as an imported type from '${this.importShortNames.get(shortName)}'. Please rename your local type or avoid importing conflicting types.`
+                );
+            }
+            uniqueNames.add(fqn);
+        });
         // Run validations on class declarations
         for(let n=0; n < this.declarations.length; n++) {
             let classDeclaration = this.declarations[n];