diff --git a/addrs/parse_ref.go b/addrs/parse_ref.go
index bad463ba8..62f244e1a 100644
--- a/addrs/parse_ref.go
+++ b/addrs/parse_ref.go
@@ -239,6 +239,18 @@ func parseRef(traversal hcl.Traversal) (*Reference, tfdiags.Diagnostics) {
 			Remaining:   remain,
 		}, diags
 
+	case "template", "lazy", "arg":
+		// These names are all pre-emptively reserved in the hope of landing
+		// some version of "template values" or "lazy expressions" feature
+		// before the next opt-in language edition, but don't yet do anything.
+		diags = diags.Append(&hcl.Diagnostic{
+			Severity: hcl.DiagError,
+			Summary:  "Reserved symbol name",
+			Detail:   fmt.Sprintf("The symbol name %q is reserved for use in a future Terraform version. If you are using a provider that already uses this as a resource type name, add the prefix \"resource.\" to force interpretation as a resource type name.", root),
+			Subject:  rootRange.Ptr(),
+		})
+		return nil, diags
+
 	default:
 		return parseResourceRef(ManagedResourceMode, rootRange, traversal)
 	}
diff --git a/addrs/parse_ref_test.go b/addrs/parse_ref_test.go
index 660725e53..f7f1949ae 100644
--- a/addrs/parse_ref_test.go
+++ b/addrs/parse_ref_test.go
@@ -605,6 +605,25 @@ func TestParseRef(t *testing.T) {
 			``,
 		},
 
+		// We have some names reserved which might be used by a
+		// still-under-discussion proposal for template values or lazy
+		// expressions.
+		{
+			`template.foo`,
+			nil,
+			`The symbol name "template" is reserved for use in a future Terraform version. If you are using a provider that already uses this as a resource type name, add the prefix "resource." to force interpretation as a resource type name.`,
+		},
+		{
+			`lazy.foo`,
+			nil,
+			`The symbol name "lazy" is reserved for use in a future Terraform version. If you are using a provider that already uses this as a resource type name, add the prefix "resource." to force interpretation as a resource type name.`,
+		},
+		{
+			`arg.foo`,
+			nil,
+			`The symbol name "arg" is reserved for use in a future Terraform version. If you are using a provider that already uses this as a resource type name, add the prefix "resource." to force interpretation as a resource type name.`,
+		},
+
 		// anything else, interpreted as a managed resource reference
 		{
 			`boop_instance.foo`,