feat(hydro_lang): support in-memory inputs for embedded Hydro programs

.config/nextest.toml

@@ -40,3 +40,7 @@ test-group = 'hydro-trybuild-group'
 [[profile.default.overrides]]
 filter = 'package(hydro_test_template)'
 test-group = 'hydro-trybuild-group'
+
+[[profile.default.overrides]]
+filter = 'package(hydro_test_embedded) & kind(example)'
+test-group = 'hydro-trybuild-group'

.vscode/settings.json

@@ -11,7 +11,6 @@
     "rust-analyzer.rustfmt.extraArgs": [
         "+nightly"
     ],
-    "rust-analyzer.cargo.features": "all",
     "editor.semanticTokenColorCustomizations": {
         "enabled": true,
         "rules": {

Cargo.toml

@@ -13,6 +13,7 @@ members = [
     "hydro_lang",
     "hydro_std",
     "hydro_test",
+    "hydro_test_embedded",
     "hydro_test_template",
     "include_mdtests",
     "lattices_macro",

hydro_lang/src/compile/builder.rs

@@ -231,7 +231,7 @@ impl<'a> FlowBuilder<'a> {
         self.with_default_optimize().with_remaining_clusters(spec)
     }
 
-    pub fn compile<D: Deploy<'a>>(self) -> CompiledFlow<'a> {
+    pub fn compile<D: Deploy<'a, InstantiateEnv = ()>>(self) -> CompiledFlow<'a> {
         self.with_default_optimize::<D>().compile()
     }
 

hydro_lang/src/compile/built.rs

@@ -316,7 +316,7 @@ impl<'a> BuiltFlow<'a> {
         self.into_deploy().with_remaining_clusters(spec)
     }
 
-    pub fn compile<D: Deploy<'a>>(self) -> CompiledFlow<'a> {
+    pub fn compile<D: Deploy<'a, InstantiateEnv = ()>>(self) -> CompiledFlow<'a> {
         self.into_deploy::<D>().compile()
     }
 

hydro_lang/src/compile/deploy.rs

@@ -262,14 +262,17 @@ impl<'a, D: Deploy<'a>> DeployFlow<'a, D> {
     /// Compiles the flow into DFIR ([`dfir_lang::graph::DfirGraph`]) including networking.
     ///
     /// (This does not compile the DFIR itself, instead use [`Self::deploy`] to compile & deploy the DFIR).
-    pub fn compile(mut self) -> CompiledFlow<'a> {
-        self.compile_internal()
+    pub fn compile(mut self) -> CompiledFlow<'a>
+    where
+        D: Deploy<'a, InstantiateEnv = ()>,
+    {
+        self.compile_internal(&mut ())
     }
 
     /// Same as [`Self::compile`] but does not invalidate `self`, for internal use.
     ///
     /// Empties `self.sidecars` and modifies `self.ir`, leaving `self` in a partial state.
-    fn compile_internal(&mut self) -> CompiledFlow<'a> {
+    pub(super) fn compile_internal(&mut self, env: &mut D::InstantiateEnv) -> CompiledFlow<'a> {
         let mut seen_tees: HashMap<_, _> = HashMap::new();
         let mut extra_stmts = SparseSecondaryMap::new();
         for leaf in self.ir.iter_mut() {
@@ -279,6 +282,7 @@ impl<'a, D: Deploy<'a>> DeployFlow<'a, D> {
                 &self.processes,
                 &self.clusters,
                 &self.externals,
+                env,
             );
         }
 
@@ -348,7 +352,7 @@ impl<'a, D: Deploy<'a>> DeployFlow<'a, D> {
             mut extra_stmts,
             mut sidecars,
             _phantom,
-        } = self.compile_internal();
+        } = self.compile_internal(env);
 
         let mut compiled = dfir;
         self.cluster_id_stmts(&mut extra_stmts);

hydro_lang/src/compile/deploy_provider.rs

@@ -118,6 +118,18 @@ pub trait Deploy<'a> {
     fn cluster_membership_stream(
         location_id: &LocationId,
     ) -> impl QuotedWithContext<'a, Box<dyn Stream<Item = (TaglessMemberId, MembershipEvent)> + Unpin>, ()>;
+
+    /// Registers an embedded input for the given ident and element type.
+    ///
+    /// Only meaningful for the embedded deployment backend. The default
+    /// implementation panics.
+    fn register_embedded_input(
+        _env: &mut Self::InstantiateEnv,
+        _ident: &syn::Ident,
+        _element_type: &syn::Type,
+    ) {
+        panic!("register_embedded_input is only supported by EmbeddedDeploy");
+    }
 }
 
 pub trait ProcessSpec<'a, D>