terraform_required_providers: fix regression with configuration_aliases (#1454)

* add failing test

* add variable with provider name when evaluating required provider

Author: bendrucker

rules/terraformrules/terraform_required_providers.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"log"
 
+	"github.com/hashicorp/hcl/v2"
 	tfaddr "github.com/hashicorp/terraform-registry-address"
 	"github.com/terraform-linters/tflint-plugin-sdk/hclext"
 	sdk "github.com/terraform-linters/tflint-plugin-sdk/tflint"
@@ -126,7 +127,14 @@ func (r *TerraformRequiredProvidersRule) Check(runner *tflint.Runner) error {
 			continue
 		}
 
-		val, diags := provider.Expr.Value(nil)
+		val, diags := provider.Expr.Value(&hcl.EvalContext{
+			Variables: map[string]cty.Value{
+				// configuration_aliases can declare additional provider instances
+				// required provider "foo" could have: configuration_aliases = [foo.a, foo.b]
+				// @see https://www.terraform.io/language/modules/develop/providers#provider-aliases-within-modules
+				name: cty.DynamicVal,
+			},
+		})
 		if diags.HasErrors() {
 			return diags
 		}

rules/terraformrules/terraform_required_providers_test.go

@@ -205,6 +205,26 @@ provider "template" {
 				},
 			},
 		},
+		{
+			Name: "version set with configuration_aliases",
+			Content: `
+terraform {
+  required_providers {
+    template = {
+			source = "hashicorp/template"
+			version = "~> 2"
+
+			configuration_aliases = [template.alias]
+		}
+  }
+}
+
+data "template_file" "foo" {
+	provider = template.alias
+}
+`,
+			Expected: tflint.Issues{},
+		},
 		{
 			Name: "version set with alias",
 			Content: `