Module outputs as input parameter is not referenced correctly

[scrocquesel-ml150]

Bicep version
0.26.170

Describe the bug
I would like to use the output of a module as the input parameter of another module. The syntax is allowed but when at deployment time, the referenced properties is missing the value attribute.

To Reproduce

// moduleA.bicep
output webAppName string = 'test'
output nonusedOutput string = 'toto'

// moduleB.bicep
param input moduleAOutputType

type moduleAOutputType = {
    webAppName: string
}

// use input.webAppName

// main.bicep
module a 'moduleA.bicep' = {
}

// valid but do not deploy
module b 'moduleB.bicep' = {
    params: {
        input: a.outputs
    }
}

// deploy
module b 'moduleB.bicep' = {
    params: {
        input: {
             webAppName: a.outputs.webAppName
        }
    }
}

Additional context

Deployment template validation failed: 'The provided value for the template parameter 'input.webAppName' is not valid. Expected a value of type 'String, Uri', but received a value of type 'Object'. Please see https://aka.ms/arm-create-parameter-file for usage details.'. (Code: InvalidTemplate)

This is what is generated when creating the object manually (working case)

 "input": {
      "value": {
          "webAppName": "[reference('a').outputs.webAppName.value]"
      }
  }

When passing outputs directly (non working case)

"input": {
      "value": "[reference('a').outputs]"
  },

and then the value is reference with "[parameters('input').webAppName]", so I guess it missed the .value part.

Could it be possible to either add the .value when the parameter is coming from the outputs object, or automatically create the value mapping ? The former would better as we may not use all properties of the output.

This would help to get rid of a lot mapping boilerplate code

[jeskew]

This seems like a gap in how Bicep translates output references into ARM JSON expressions. In the second case, the ARM expression should look something like:

"input": {
  "value": "[toObject(items(reference('a').outputs), lambda('kvp', lambdaVariables('kvp').key), lambda('kvp', lambdaVariables('kvp').value.value))]"
}

We block using such an expression directly in Bicep since each property on a reference to module outputs uses the type of the output rather than an object with a value property: