render runtime crates from templates dynamically (#962)

Closes #863

- The entirety of "runtime" codegen is now following a strict MVC model,
and the source code is rendered from the same model object. We should be
able to further improve/refactor this model object in #638
- Complex model construction can be strongly-typed in Rust, while
rendering is left to templates, as they are much easier to read and
modify, and also have powerful macros/imports/callbacks, etc...
- I also (partially) improved the DX when working with templates in
terminal, by rendering their errors as an `ariadne` report, with
best-guess source location in the template. A temporary workaround
waiting for Keats/tera#885
- Now both stubs and output crates are rendered from the same source
templates, removing a few internal hacks and the need for
`![allow(dead_code)]` and `![allow(unused)]` everywhere (will follow up
on this cleanup separately).
- We no longer have to maintain explicit paths and copy files around in
the code generator. All templates generate their output file relative to
their location, which means we can split and refactor code into as many
templates/sub-modules as needed, following standard rust idioms.

Cargo.toml

@@ -13,10 +13,13 @@ members = [
     "crates/codegen/language/internal_macros",
     "crates/codegen/language/macros",
     "crates/codegen/language/tests",
-    "crates/codegen/parser/generator",
-    "crates/codegen/parser/runtime",
+    "crates/codegen/runtime/cargo",
+    "crates/codegen/runtime/generator",
+    "crates/codegen/runtime/node_addon",
+    "crates/codegen/runtime/npm",
     "crates/codegen/spec",
     "crates/codegen/testing",
+
     "crates/infra/cli",
     "crates/infra/utils",
 
@@ -47,10 +50,13 @@ codegen_language_definition = { path = "crates/codegen/language/definition" }
 codegen_language_internal_macros = { path = "crates/codegen/language/internal_macros" }
 codegen_language_macros = { path = "crates/codegen/language/macros" }
 codegen_language_tests = { path = "crates/codegen/language/tests" }
-codegen_parser_generator = { path = "crates/codegen/parser/generator" }
-codegen_parser_runtime = { path = "crates/codegen/parser/runtime" }
+codegen_runtime_cargo = { path = "crates/codegen/runtime/cargo" }
+codegen_runtime_generator = { path = "crates/codegen/runtime/generator" }
+codegen_runtime_node_addon = { path = "crates/codegen/runtime/node_addon" }
+codegen_runtime_npm = { path = "crates/codegen/runtime/npm" }
 codegen_spec = { path = "crates/codegen/spec" }
 codegen_testing = { path = "crates/codegen/testing" }
+
 infra_cli = { path = "crates/infra/cli" }
 infra_utils = { path = "crates/infra/utils" }
 

crates/codegen/language/tests/src/fail/mod.rs

@@ -21,7 +21,6 @@ fn run_trybuild() {
     let tests = FileWalker::from_directory(crate_dir)
         .find(["src/fail/**/test.rs"])
         .unwrap()
-        .into_iter()
         .collect::<Vec<_>>();
 
     assert!(!tests.is_empty(), "No tests found.");