Fix external inputs breaking base parameter spreads

[polatengin]

Description

Fixes #19954.

When a parent parameter file contains an externalInput, using the spread operator with another inherited parameter could fail with BCP338.

In this PR;

I've added tests that reproduce the issue with ...base.B

I've fixed the issue in ExpressionBuilder by evaluating only the selected base parameter

I've also added coverage for object and array spreads, property access, bracket access, and nested parameter files

Checklist

• I have read and adhere to the contribution guide.

Microsoft Reviewers: Open in CodeFlow

[github-actions]

Test this change out locally with the following install scripts (Action run 29787155084)

VSCode

• Mac/Linux

  bash <(curl -Ls https://aka.ms/bicep/nightly-vsix.sh) --run-id 29787155084

• Windows

  iex "& { $(irm https://aka.ms/bicep/nightly-vsix.ps1) } -RunId 29787155084"

Azure CLI

• Mac/Linux

  bash <(curl -Ls https://aka.ms/bicep/nightly-cli.sh) --run-id 29787155084

• Windows

  iex "& { $(irm https://aka.ms/bicep/nightly-cli.ps1) } -RunId 29787155084"

[levimatheri]

Can we add a test case for this? I just tested it with your fix, but seems it's failing:

shared.bicepparam:

using none
param external = externalInput('foo', 'bar')
param B = {
  parent: 'parent'
}

main.bicepparam:

using 'main.bicep'

extends 'shared.bicepparam'
param B = {
  ...base.external
  something: 'something'
}

[polatengin]

Can we add a test case for this? I just tested it with your fix, but seems it's failing:

@levimatheri I've added the regression test and fixed dependency tracking for selected base parameters containing externalInput.

I moved ProcessInlinableSymbol from a local function inside VisitVariableAccessSyntax to a private method so the same dependency propagation logic can also be reused by VisitPropertyAccessSyntax.

This allows base.external to mark the dependent assignment for inlining and emit the expected externalInputs(...) expression.