Lower Effect Unit command entries through the existing closure

README.md

@@ -28,8 +28,9 @@ cargo run -- dump mir examples/basic.purs
 `build <file.purs>...` resolves and links every listed module with the standard
 library from `stdlib/lib` and writes the artifact. `wat <file.purs>...` renders
 the text form. `dump <core|cc|mir> <file.purs>` prints an intermediate IR for
-debugging. `main` must be a zero-argument `Int` declaration; its value becomes
-the process exit code.
+debugging. A selected `main :: Int` returns its value as the process exit code.
+A selected `main :: Effect Unit` runs that action once and returns 0; a trap
+still propagates.
 
 For a guided, interactive walkthrough of P0 through P11, use the React
 application in [`psrs-explorer/`](psrs-explorer/). It labels compact teaching
@@ -45,11 +46,11 @@ what remains in each layer.
 | Gate | Measured | Scope |
 | --- | --- | --- |
 | L0/L1 lexing, layout, parsing | 904/908 | non-FFI `layout`, `passing`, `failing`, `warning` files; the four differences are recorded DEC-16 intentional differences |
-| L2 resolution | 54/70 failing, 52/413 passing | official `errorCode`s; 106 `passing` files stop in surface lowering |
-| L3 kinds | 27/48 failing | official kind `errorCode`s |
-| L4 types | 12/40 failing | official `errorCode`s; most mismatches blocked on a missing library module |
-| L5 classes | 41/81 failing | official `errorCode`s; most mismatches blocked on a missing library module |
-| L6/M7 runtime | 0/413 passing | 244 blocked on a missing module, 106 in surface lowering |
+| L2 resolution | 72/72 failing, 270/413 passing | official `errorCode`s; 53 `passing` files stop on a missing module and 86 at P3 |
+| L3 kinds | 35/48 failing | official kind `errorCode`s |
+| L4 types | 35/50 failing | official `errorCode`s |
+| L5 classes | 53/80 failing | official `errorCode`s |
+| L6/M7 runtime | 124/413 passing | all 124 exit 0; 63 have no selected `main`; 53 stop on a missing module |
 | M8 warnings, optimization | not measured | no scoreboard exists |
 
 Run the scoreboards yourself:

crates/psrs-backend/src/abi/link/mod.rs

@@ -1,21 +1,23 @@
 //! Target-aware linking helpers for source WIT bindings.
 //!
-//! A foreign import's resolved source type is interned into the Core type table
-//! so the backend can refer to it by identity. A structurally equal Core type
-//! already in the table is reused, so a foreign signature shares the canonical
-//! representation of the same type used elsewhere in the module. This replaces
-//! recovering the type by structural search at the CC boundary.
+//! WIT declarations consume the checked external schemes carried by Core.
+//! Structural HIR interning remains available only to isolated ABI fixtures;
+//! production linking never reconstructs the checked source type from HIR.
 
+#[cfg(test)]
 use psrs_core::{Module as CoreModule, Type as CoreType, TypeConstructor, TypeId as CoreTypeId};
+#[cfg(test)]
 use psrs_hir::{BuiltinType, Type as HirType, TypeKind as HirTypeKind};
 
 /// Interns the resolved source type of a foreign import and returns its
 /// [`CoreTypeId`]. The type is appended to the module type table when no
 /// structurally equal type is present.
+#[cfg(test)]
 pub(crate) fn intern_source_type(module: &mut CoreModule, ty: &HirType) -> Option<CoreTypeId> {
     intern_into(&mut module.types, ty)
 }
 
+#[cfg(test)]
 fn intern_into(types: &mut Vec<CoreType>, ty: &HirType) -> Option<CoreTypeId> {
     let core = match &ty.kind {
         HirTypeKind::Constructor(BuiltinType::Int) => {
@@ -91,13 +93,15 @@ fn intern_into(types: &mut Vec<CoreType>, ty: &HirType) -> Option<CoreTypeId> {
     Some(intern_core_type(types, core))
 }
 
+#[cfg(test)]
 fn is_array_constructor(types: &[CoreType], id: CoreTypeId) -> bool {
     matches!(
         types.get(id.0 as usize),
         Some(CoreType::Constructor(TypeConstructor::Array))
     )
 }
 
+#[cfg(test)]
 fn is_array_element(types: &[CoreType], id: CoreTypeId) -> bool {
     match types.get(id.0 as usize) {
         // `Unit` is a primitive but has no canonical list element.
@@ -122,6 +126,7 @@ fn is_array_element(types: &[CoreType], id: CoreTypeId) -> bool {
     }
 }
 
+#[cfg(test)]
 fn is_record(types: &[CoreType], id: CoreTypeId) -> bool {
     let Some(CoreType::Application(function, _)) = types.get(id.0 as usize) else {
         return false;
@@ -132,13 +137,15 @@ fn is_record(types: &[CoreType], id: CoreTypeId) -> bool {
     )
 }
 
+#[cfg(test)]
 fn is_user_type(types: &[CoreType], id: CoreTypeId) -> bool {
     matches!(
         types.get(id.0 as usize),
         Some(CoreType::Constructor(TypeConstructor::User(_)))
     )
 }
 
+#[cfg(test)]
 fn intern_core_type(types: &mut Vec<CoreType>, core: CoreType) -> CoreTypeId {
     if let Some(index) = types.iter().position(|existing| *existing == core) {
         return CoreTypeId(index as u32);

crates/psrs-backend/src/abi/link/tests.rs

@@ -13,6 +13,7 @@ fn module() -> CoreModule {
         id: ModuleId(0),
         name: "Main".into(),
         externals: Vec::new(),
+        external_types: Vec::new(),
         types: vec![
             CoreType::Constructor(psrs_core::TypeConstructor::Int),
             CoreType::Constructor(psrs_core::TypeConstructor::Number),

crates/psrs-backend/src/abi/mod.rs

@@ -23,6 +23,7 @@ use canonical::{
     resolve as resolve_canonical,
 };
 pub use handles::{HandleMode, HandleResource};
+#[cfg(test)]
 pub(crate) use link::intern_source_type;
 use validation::{unsupported_shape, wasi_interface_enabled};
 

crates/psrs-backend/src/abi/tests/lists.rs

@@ -18,6 +18,7 @@ fn empty_core() -> CoreModule {
         id: ModuleId(0),
         name: "Main".into(),
         externals: Vec::new(),
+        external_types: Vec::new(),
         types: Vec::new(),
         newtype_ids: Vec::new(),
         opaque_ids: Vec::new(),

crates/psrs-backend/src/abi/tests/mod.rs

@@ -19,6 +19,7 @@ fn empty_core_module() -> psrs_core::Module {
         id: psrs_hir::ModuleId(0),
         name: "Main".into(),
         externals: Vec::new(),
+        external_types: Vec::new(),
         types: Vec::new(),
         newtype_ids: Vec::new(),
         opaque_ids: Vec::new(),

crates/psrs-backend/src/bindings/mod.rs

@@ -3,7 +3,7 @@
 use crate::BackendError;
 use crate::cc;
 use psrs_core::{Module as CoreModule, TypeId as CoreTypeId};
-use psrs_hir::{ExternalKind, SymbolId, Type as HirType};
+use psrs_hir::{ExternalKind, ModuleId, SymbolId};
 use std::collections::{HashMap, HashSet};
 
 /// The complete input consumed by P9. Platform binding metadata is kept beside
@@ -23,11 +23,12 @@ pub struct ExternalBindings {
 impl ExternalBindings {
     /// Extracts platform binding metadata while crossing the Core boundary.
     /// CC receives only this side table and therefore never needs to inspect
-    /// WIT names or HIR external kinds. Each declaration's resolved source type
-    /// is interned into the Core type table and recorded as a `type_id`, so CC
-    /// derives its layout from that identity instead of re-deriving it.
-    pub(crate) fn from_core(module: &mut CoreModule) -> Self {
-        let declared: Vec<(SymbolId, String, String, Option<HirType>)> = module
+    /// WIT names or HIR external kinds. Each declaration's checked,
+    /// synonym-expanded source scheme is read from Core's external signature
+    /// table and recorded as a `type_id`, so CC derives its layout from that
+    /// identity instead of re-deriving it from raw HIR.
+    pub(crate) fn from_core(module: &CoreModule) -> Self {
+        let imports = module
             .externals
             .iter()
             .filter_map(|external| {
@@ -38,31 +39,24 @@ impl ExternalBindings {
                 else {
                     return None;
                 };
-                Some((
-                    external.symbol,
-                    interface.clone(),
-                    function.clone(),
-                    external.signature.clone(),
-                ))
+                let checked = module
+                    .external_types
+                    .iter()
+                    .find(|checked| checked.symbol == external.symbol);
+                Some(ExternalBinding {
+                    symbol: external.symbol,
+                    source_module: checked.map_or(module.id, |checked| checked.source_module),
+                    interface: interface.clone(),
+                    function: function.clone(),
+                    type_id: checked.map(|checked| checked.ty),
+                    span: external
+                        .signature
+                        .as_ref()
+                        .map(|signature| signature.span)
+                        .unwrap_or(module.span),
+                })
             })
             .collect();
-        let module_span = module.span;
-        let mut imports = Vec::with_capacity(declared.len());
-        for (symbol, interface, function, signature) in declared {
-            let span = signature
-                .as_ref()
-                .map_or(module_span, |signature| signature.span);
-            let type_id = signature
-                .as_ref()
-                .and_then(|signature| crate::abi::intern_source_type(module, signature));
-            imports.push(ExternalBinding {
-                symbol,
-                interface,
-                function,
-                type_id,
-                span,
-            });
-        }
         Self { imports }
     }
 
@@ -84,7 +78,7 @@ impl ExternalBindings {
                 .map_err(|message| {
                     vec![
                         BackendError::new("P8 WIT linking", binding.span, message)
-                            .with_module(binding.symbol.module),
+                            .with_module(binding.source_module),
                     ]
                 })?;
             if let Some(reason) = &import.unsupported {
@@ -94,7 +88,7 @@ impl ExternalBindings {
                         binding.span,
                         format!("WIT import `{qualified}` is unsupported: {reason}"),
                     )
-                    .with_module(binding.symbol.module),
+                    .with_module(binding.source_module),
                 ]);
             }
             let Some(type_id) = binding.type_id else {
@@ -104,14 +98,14 @@ impl ExternalBindings {
                         binding.span,
                         format!("WIT import `{qualified}` has no resolved source type"),
                     )
-                    .with_module(binding.symbol.module),
+                    .with_module(binding.source_module),
                 ]);
             };
             crate::abi::link::validate_import_signature(&import, module, type_id).map_err(
                 |message| {
                     vec![
                         BackendError::new("P8 WIT linking", binding.span, message)
-                            .with_module(binding.symbol.module),
+                            .with_module(binding.source_module),
                     ]
                 },
             )?;
@@ -225,6 +219,7 @@ impl ExternalBindings {
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct ExternalBinding {
     pub symbol: SymbolId,
+    pub source_module: ModuleId,
     pub interface: String,
     pub function: String,
     /// The declaration's resolved source type, interned in the module type

crates/psrs-backend/src/bindings/tests.rs

@@ -26,6 +26,7 @@ fn wit_external(symbol: SymbolId) -> ExternalSymbol {
 fn binding(symbol: SymbolId) -> ExternalBinding {
     ExternalBinding {
         symbol,
+        source_module: ModuleId(0),
         interface: "wasi:cli/stdout@0.2.12".into(),
         function: "log".into(),
         type_id: None,
@@ -39,6 +40,7 @@ fn module(externals: Vec<ExternalSymbol>) -> CoreModule {
         id: ModuleId(1),
         name: "Main".into(),
         externals,
+        external_types: Vec::new(),
         types: Vec::new(),
         newtype_ids: Vec::new(),
         opaque_ids: Vec::new(),

crates/psrs-backend/src/cc/case/coverage/tests/mod.rs

@@ -20,6 +20,7 @@ fn module(types: Vec<Type>, constructors: Vec<psrs_core::ConstructorInfo>) -> Mo
         id: ModuleId(0),
         name: "CoverageTest".to_owned(),
         externals: Vec::new(),
+        external_types: Vec::new(),
         types,
         newtype_ids: Vec::new(),
         opaque_ids: Vec::new(),

crates/psrs-backend/src/cc/case/decision/compile/oracle_record_tests.rs

@@ -26,6 +26,7 @@ fn module() -> Module {
         id: ModuleId(0),
         name: "RecordOracleTest".into(),
         externals: Vec::new(),
+        external_types: Vec::new(),
         types: vec![
             Type::Constructor(TypeConstructor::User(u)),
             Type::Constructor(psrs_core::TypeConstructor::Int),

crates/psrs-backend/src/cc/case/decision/compile/oracle_tests.rs

@@ -33,6 +33,7 @@ fn module() -> Module {
         id: ModuleId(0),
         name: "OracleTest".into(),
         externals: Vec::new(),
+        external_types: Vec::new(),
         types: vec![
             Type::Constructor(TypeConstructor::User(t)),
             Type::Constructor(TypeConstructor::User(u)),

crates/psrs-backend/src/cc/case/decision/compile/tests/mod.rs

@@ -14,6 +14,7 @@ fn bool_module() -> (Module, SymbolId, SymbolId) {
         id: ModuleId(0),
         name: "DecisionTest".into(),
         externals: Vec::new(),
+        external_types: Vec::new(),
         types: vec![Type::Constructor(TypeConstructor::User(type_id))],
         newtype_ids: Vec::new(),
         opaque_ids: Vec::new(),

crates/psrs-backend/src/cc/case/decision/realize/tests/mod.rs

@@ -29,6 +29,7 @@ fn compiled_root_switch_resolves_the_realizer_root_slot() {
         id: module_id,
         name: "DecisionRealizeTest".into(),
         externals: Vec::new(),
+        external_types: Vec::new(),
         types: vec![Type::Constructor(TypeConstructor::User(type_id))],
         newtype_ids: Vec::new(),
         opaque_ids: Vec::new(),

crates/psrs-backend/src/cc/case/decision/realize/tests/nested_tests.rs

@@ -27,6 +27,7 @@ fn nested_sum_patterns_project_once_per_selected_constructor_and_trap_missing_ta
         id: module_id,
         name: "NestedDecisionTest".into(),
         externals: Vec::new(),
+        external_types: Vec::new(),
         types: vec![
             Type::Constructor(TypeConstructor::User(outer_type)),
             Type::Constructor(TypeConstructor::User(bool_type)),

crates/psrs-backend/src/cc/case/decision/realize/tests/newtype_tests.rs

@@ -23,6 +23,7 @@ fn newtype_constructor_erases_before_nested_enum_dispatch() {
         id: module_id,
         name: "NewtypeDecisionTest".into(),
         externals: Vec::new(),
+        external_types: Vec::new(),
         types: vec![
             Type::Constructor(TypeConstructor::User(wrapper_type)),
             Type::Constructor(TypeConstructor::User(bool_type)),

crates/psrs-backend/src/cc/case/decision/realize/tests/parameterized_tests/mod.rs

@@ -22,6 +22,7 @@ fn parameterized_array_field_projection_uses_its_stored_canonical_array() {
         id: module_id,
         name: "ParameterizedArrayDecisionTest".into(),
         externals: Vec::new(),
+        external_types: Vec::new(),
         types: vec![
             Type::Constructor(TypeConstructor::User(wrap_type)),
             Type::Variable(TypeVariableId(0)),
@@ -172,6 +173,7 @@ fn nested_parameterized_projection_keeps_each_canonical_field() {
         id: module_id,
         name: "NestedParameterizedDecisionTest".into(),
         externals: Vec::new(),
+        external_types: Vec::new(),
         types: vec![
             Type::Constructor(TypeConstructor::User(inner_type)),
             Type::Constructor(TypeConstructor::User(outer_type)),
@@ -320,6 +322,7 @@ fn generic_record_pattern_projects_its_canonical_array_field() {
         id: module_id,
         name: "GenericRecordDecisionTest".into(),
         externals: Vec::new(),
+        external_types: Vec::new(),
         types: vec![
             Type::Variable(TypeVariableId(0)),
             Type::Constructor(TypeConstructor::Array),

crates/psrs-backend/src/cc/case/decision/realize/tests/product_tests.rs

@@ -23,6 +23,7 @@ fn single_constructor_product_dispatch_projects_and_binds_first_row_once() {
         id: module_id,
         name: "ProductDecisionTest".into(),
         externals: Vec::new(),
+        external_types: Vec::new(),
         types: vec![
             Type::Constructor(TypeConstructor::User(type_id)),
             Type::Constructor(psrs_core::TypeConstructor::Int),

crates/psrs-backend/src/cc/case/decision/realize/tests/record_tests.rs

@@ -25,6 +25,7 @@ fn nested_record_patterns_share_one_product_projection_and_keep_source_spans() {
         id: module_id,
         name: "RecordDecisionTest".into(),
         externals: Vec::new(),
+        external_types: Vec::new(),
         types: vec![
             Type::Constructor(TypeConstructor::User(bool_type)),
             Type::Constructor(psrs_core::TypeConstructor::Int),

crates/psrs-backend/src/cc/layout/tests/mod.rs

@@ -23,6 +23,7 @@ fn empty_module(types: Vec<Type>) -> Module {
         id: ModuleId(0),
         name: "LayoutKeysTest".into(),
         externals: Vec::new(),
+        external_types: Vec::new(),
         types,
         newtype_ids: Vec::new(),
         opaque_ids: Vec::new(),
@@ -170,6 +171,7 @@ fn equal_normalized_function_signatures_share_one_signature_id() {
         id: ModuleId(0),
         name: "SignatureInterningTest".into(),
         externals: Vec::new(),
+        external_types: Vec::new(),
         types,
         newtype_ids: Vec::new(),
         opaque_ids: Vec::new(),
@@ -287,6 +289,7 @@ fn integer_capture_module(capture: Type) -> Module {
         id: ModuleId(0),
         name: "IntegerCaptureTest".into(),
         externals: Vec::new(),
+        external_types: Vec::new(),
         types: vec![capture, Type::Constructor(psrs_core::TypeConstructor::Int)],
         newtype_ids: Vec::new(),
         opaque_ids: Vec::new(),
@@ -371,6 +374,7 @@ fn an_opaque_handle_and_an_array_of_handles_have_scalar_layouts() {
         id: module_id,
         name: "OpaqueHandleLayoutTest".into(),
         externals: Vec::new(),
+        external_types: Vec::new(),
         types: vec![
             Type::Constructor(TypeConstructor::User(opaque)),
             Type::Constructor(TypeConstructor::Array),