Upgrade HCL to fix optional attr default crash

Also add regression test coverage of the crash. This would occur when
objects with optional attributes had default values of different type
from the attribute type, and the objects were members of a collection.

For example:

list(object({
  a = optional(set(string), [])
}))

If this type constraint is applied to a variable value where one object
has a set(string) value for a, and the other object applies the empty
tuple default, Terraform would crash.

Author: alisdair

go.mod

@@ -42,7 +42,7 @@ require (
 	github.com/hashicorp/go-uuid v1.0.3
 	github.com/hashicorp/go-version v1.6.0
 	github.com/hashicorp/hcl v0.0.0-20170504190234-a4b07c25de5f
-	github.com/hashicorp/hcl/v2 v2.14.0
+	github.com/hashicorp/hcl/v2 v2.14.1
 	github.com/hashicorp/terraform-config-inspect v0.0.0-20210209133302-4fd17a0faac2
 	github.com/hashicorp/terraform-registry-address v0.0.0-20220623143253-7d51757b572c
 	github.com/hashicorp/terraform-svchost v0.0.0-20200729002733-f050f53b9734

go.sum

@@ -387,8 +387,8 @@ github.com/hashicorp/golang-lru v0.5.1/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ
 github.com/hashicorp/hcl v0.0.0-20170504190234-a4b07c25de5f h1:UdxlrJz4JOnY8W+DbLISwf2B8WXEolNRA8BGCwI9jws=
 github.com/hashicorp/hcl v0.0.0-20170504190234-a4b07c25de5f/go.mod h1:oZtUIOe8dh44I2q6ScRibXws4Ajl+d+nod3AaR9vL5w=
 github.com/hashicorp/hcl/v2 v2.0.0/go.mod h1:oVVDG71tEinNGYCxinCYadcmKU9bglqW9pV3txagJ90=
-github.com/hashicorp/hcl/v2 v2.14.0 h1:jX6+Q38Ly9zaAJlAjnFVyeNSNCKKW8D0wvyg7vij5Wc=
-github.com/hashicorp/hcl/v2 v2.14.0/go.mod h1:e4z5nxYlWNPdDSNYX+ph14EvWYMFm3eP0zIUqPc2jr0=
+github.com/hashicorp/hcl/v2 v2.14.1 h1:x0BpjfZ+CYdbiz+8yZTQ+gdLO7IXvOut7Da+XJayx34=
+github.com/hashicorp/hcl/v2 v2.14.1/go.mod h1:e4z5nxYlWNPdDSNYX+ph14EvWYMFm3eP0zIUqPc2jr0=
 github.com/hashicorp/jsonapi v0.0.0-20210826224640-ee7dae0fb22d h1:9ARUJJ1VVynB176G1HCwleORqCaXm/Vx0uUi0dL26I0=
 github.com/hashicorp/jsonapi v0.0.0-20210826224640-ee7dae0fb22d/go.mod h1:Yog5+CPEM3c99L1CL2CFCYoSzgWm5vTU58idbRUaLik=
 github.com/hashicorp/logutils v1.0.0/go.mod h1:QIAnNjmIWmVIIkWDTG1z5v++HQmx9WQRO+LraFDTW64=

internal/terraform/context_apply_test.go

@@ -12165,6 +12165,70 @@ output "out" {
 	}
 }
 
+func TestContext2Apply_moduleVariableOptionalAttributesDefaultChild(t *testing.T) {
+	m := testModuleInline(t, map[string]string{
+		"main.tf": `
+variable "in" {
+  type    = list(object({
+    a = optional(set(string))
+  }))
+  default = [
+	{ a = [ "foo" ] },
+	{ },
+  ]
+}
+
+module "child" {
+  source = "./child"
+  in     = var.in
+}
+
+output "out" {
+  value = module.child.out
+}
+`,
+		"child/main.tf": `
+variable "in" {
+  type    = list(object({
+    a = optional(set(string), [])
+  }))
+  default = []
+}
+
+output "out" {
+  value = var.in
+}
+`,
+	})
+
+	ctx := testContext2(t, &ContextOpts{})
+
+	// We don't specify a value for the variable here, relying on its defined
+	// default.
+	plan, diags := ctx.Plan(m, states.NewState(), SimplePlanOpts(plans.NormalMode, testInputValuesUnset(m.Module.Variables)))
+	if diags.HasErrors() {
+		t.Fatal(diags.ErrWithWarnings())
+	}
+
+	state, diags := ctx.Apply(plan, m)
+	if diags.HasErrors() {
+		t.Fatal(diags.ErrWithWarnings())
+	}
+
+	got := state.RootModule().OutputValues["out"].Value
+	want := cty.ListVal([]cty.Value{
+		cty.ObjectVal(map[string]cty.Value{
+			"a": cty.SetVal([]cty.Value{cty.StringVal("foo")}),
+		}),
+		cty.ObjectVal(map[string]cty.Value{
+			"a": cty.SetValEmpty(cty.String),
+		}),
+	})
+	if !want.RawEquals(got) {
+		t.Fatalf("wrong result\ngot:  %#v\nwant: %#v", got, want)
+	}
+}
+
 func TestContext2Apply_provisionerSensitive(t *testing.T) {
 	m := testModule(t, "apply-provisioner-sensitive")
 	p := testProvider("aws")