Fixes: #6934
With this snippet of code:
```
func main() {
pulumi.Run(func(ctx *pulumi.Context) error {
// Create an AWS resource (S3 Bucket)
vpc, err := ec2.NewVpc(ctx, "main", &ec2.VpcArgs{
CidrBlock: pulumi.String("10.0.0.0/16"),
})
if err != nil {
return err
}
rt, err := ec2.NewRouteTable(ctx, "example", &ec2.RouteTableArgs{
VpcId: vpc.ID(),
})
// Export the name of the bucket
ctx.Export("rt", rt)
return nil
})
}
```
the CLI would panic on the diff as follows:
```
panic: fatal: An assertion has failed
goroutine 249 [running]:
github.com/pulumi/pulumi/sdk/v3/go/common/util/contract.failfast(...)
/private/tmp/pulumi-20210422-70582-1bpvlru/sdk/go/common/util/contract/failfast.go:23
github.com/pulumi/pulumi/sdk/v3/go/common/util/contract.Assert(...)
/private/tmp/pulumi-20210422-70582-1bpvlru/sdk/go/common/util/contract/assert.go:26
github.com/pulumi/pulumi/pkg/v3/engine.printPropertyValue(0xc0005d41b0, 0x57cce00, 0xc001da9050, 0x0, 0x1, 0x5932853, 0x4, 0x0)
/private/tmp/pulumi-20210422-70582-1bpvlru/pkg/engine/diff.go:511 +0x1485
```
This was due to the entire object being added to the output and
the property being a ResourceReference
On the changing of the code to use a switch statement, we can
now include the ResourceReference and ensure that we catch any
missing case statements with a panic as default
This means the same piece of code now outputs to the CLI as
follows:
```
Outputs:
rt: {
URN: "urn:pulumi:dev::testing-new-engine-diff::aws:ec2/routeTable:RouteTable::example"
ID : "rtb-09b37608ec34f3b49"
PackageVersion: ""
}
Resources:
3 unchanged
Duration: 2s
```