This change detects duplicate object names (monikers) and issues a nice
error message with source context include. For example:
index.ts(260,22): error MU2006: Duplicate objects with the same name:
prod::ec2instance:index::aws:ec2/securityGroup:SecurityGroup::group
The prior code asserted and failed abruptly, whereas this actually points
us to the offending line of code:
let group1 = new aws.ec2.SecurityGroup("group", { ... });
let group2 = new aws.ec2.SecurityGroup("group", { ... });
^^^^^^^^^^^^^^^^^^^^^^^^^
877fa131eb