title: Error: Invalid provider configuration alias
body: <p>After upgrade to version Terraform v0.12.0 and updating config using "terraform 0.12upgrade" </p>
  
  <p>I get error below for terraform init</p>
  
  <p>the alias are set to variables in main.tf and are passed in from azure or substituted. </p>
  
  <blockquote>
    <p>There are some problems with the configuration, described below.</p>
    
    <p>The Terraform configuration must be valid before initialization so
    that Terraform can determine which modules and providers need to be
    installed.</p>
    
    <p>Error: Invalid provider configuration alias</p>
    
    <p>An alias must be a valid name. A name must start with a letter and may
    contain only letters, digits, underscores, and dashes.</p>
  </blockquote>
  
  <pre><code> `provider "azurerm {
    subscription_id = var.arm_subscription_id
    tenant_id       = var.tenant_id
    alias           = "$${var.myservers_name}"
  }`"
  </code></pre>