Support implementing trait functions in impl blocks

Author: cburgdorf

crates/analyzer/src/context.rs

@@ -1,5 +1,7 @@
-use crate::namespace::items::{Class, ContractId, DiagnosticSink, EventId, FunctionId, Item};
-use crate::namespace::types::{SelfDecl, Struct, Type};
+use crate::namespace::items::{
+    Class, ContractId, DiagnosticSink, EventId, FunctionId, FunctionSigId, Item, TraitId,
+};
+use crate::namespace::types::{Generic, SelfDecl, Struct, Type};
 use crate::AnalyzerDb;
 use crate::{
     builtins::{ContractTypeMethod, GlobalFunction, Intrinsic, ValueMethod},
@@ -361,7 +363,12 @@ impl Location {
     pub fn assign_location(typ: &Type) -> Self {
         match typ {
             Type::Base(_) | Type::Contract(_) => Location::Value,
-            Type::Array(_) | Type::Tuple(_) | Type::String(_) | Type::Struct(_) => Location::Memory,
+            // For now assume that generics can only ever refer to structs
+            Type::Array(_)
+            | Type::Tuple(_)
+            | Type::String(_)
+            | Type::Struct(_)
+            | Type::Generic(_) => Location::Memory,
             other => panic!("Type {other} can not be assigned, returned or passed"),
         }
     }
@@ -458,11 +465,21 @@ pub enum CallType {
         class: Class,
         function: FunctionId,
     },
+    // some_struct_or_contract.foo()
     ValueMethod {
-        is_self: bool,
         class: Class,
         method: FunctionId,
     },
+    // some_trait.foo()
+    // The reason this can not use `ValueMethod` is mainly because the trait might not have a function implementation
+    // and even if it had it might not be the one that ends up getting executed. An `impl` block will decide that.
+    TraitValueMethod {
+        trait_id: TraitId,
+        method: FunctionSigId,
+        // Traits can not directly be used as types but can act as bounds for generics. This is the generic type
+        // that the method is called on.
+        generic_type: Generic,
+    },
     External {
         contract: ContractId,
         function: FunctionId,
@@ -479,6 +496,7 @@ impl CallType {
             | BuiltinValueMethod { .. }
             | TypeConstructor(_)
             | Intrinsic(_)
+            | TraitValueMethod { .. }
             | BuiltinAssociatedFunction { .. } => None,
             AssociatedFunction { function: id, .. }
             | ValueMethod { method: id, .. }
@@ -497,6 +515,7 @@ impl CallType {
             | CallType::ValueMethod { method: id, .. }
             | CallType::External { function: id, .. }
             | CallType::Pure(id) => id.name(db),
+            CallType::TraitValueMethod { method: id, .. } => id.name(db),
             CallType::TypeConstructor(typ) => typ.name(),
         }
     }

crates/analyzer/src/db.rs

@@ -1,10 +1,10 @@
 use crate::context::{Analysis, Constant, FunctionBody};
 use crate::errors::{ConstEvalError, TypeError};
 use crate::namespace::items::{
-    self, ContractFieldId, ContractId, DepGraphWrapper, EventId, FunctionId, Impl, IngotId, Item,
-    ModuleConstantId, ModuleId, StructFieldId, StructId, TraitId, TypeAliasId,
+    self, ContractFieldId, ContractId, DepGraphWrapper, EventId, FunctionId, FunctionSigId, ImplId,
+    IngotId, Item, ModuleConstantId, ModuleId, StructFieldId, StructId, TraitId, TypeAliasId,
 };
-use crate::namespace::types;
+use crate::namespace::types::{self, Type};
 use fe_common::db::{SourceDb, SourceDbStorage, Upcast, UpcastMut};
 use fe_common::{SourceFileId, Span};
 use fe_parser::ast;
@@ -26,6 +26,8 @@ pub trait AnalyzerDb: SourceDb + Upcast<dyn SourceDb> + UpcastMut<dyn SourceDb>
     #[salsa::interned]
     fn intern_trait(&self, data: Rc<items::Trait>) -> TraitId;
     #[salsa::interned]
+    fn intern_impl(&self, data: Rc<items::Impl>) -> ImplId;
+    #[salsa::interned]
     fn intern_struct_field(&self, data: Rc<items::StructField>) -> StructFieldId;
     #[salsa::interned]
     fn intern_type_alias(&self, data: Rc<items::TypeAlias>) -> TypeAliasId;
@@ -34,6 +36,8 @@ pub trait AnalyzerDb: SourceDb + Upcast<dyn SourceDb> + UpcastMut<dyn SourceDb>
     #[salsa::interned]
     fn intern_contract_field(&self, data: Rc<items::ContractField>) -> ContractFieldId;
     #[salsa::interned]
+    fn intern_function_sig(&self, data: Rc<items::FunctionSig>) -> FunctionSigId;
+    #[salsa::interned]
     fn intern_function(&self, data: Rc<items::Function>) -> FunctionId;
     #[salsa::interned]
     fn intern_event(&self, data: Rc<items::Event>) -> EventId;
@@ -63,9 +67,11 @@ pub trait AnalyzerDb: SourceDb + Upcast<dyn SourceDb> + UpcastMut<dyn SourceDb>
     #[salsa::invoke(queries::module::module_all_items)]
     fn module_all_items(&self, module: ModuleId) -> Rc<[Item]>;
     #[salsa::invoke(queries::module::module_all_impls)]
-    fn module_all_impls(&self, module: ModuleId) -> Rc<[Impl]>;
+    fn module_all_impls(&self, module: ModuleId) -> Rc<[ImplId]>;
     #[salsa::invoke(queries::module::module_item_map)]
     fn module_item_map(&self, module: ModuleId) -> Analysis<Rc<IndexMap<SmolStr, Item>>>;
+    #[salsa::invoke(queries::module::module_impl_map)]
+    fn module_impl_map(&self, module: ModuleId) -> Analysis<Rc<IndexMap<(TraitId, Type), ImplId>>>;
     #[salsa::invoke(queries::module::module_contracts)]
     fn module_contracts(&self, module: ModuleId) -> Rc<[ContractId]>;
     #[salsa::invoke(queries::module::module_structs)]
@@ -134,7 +140,7 @@ pub trait AnalyzerDb: SourceDb + Upcast<dyn SourceDb> + UpcastMut<dyn SourceDb>
 
     // Function
     #[salsa::invoke(queries::functions::function_signature)]
-    fn function_signature(&self, id: FunctionId) -> Analysis<Rc<types::FunctionSignature>>;
+    fn function_signature(&self, id: FunctionSigId) -> Analysis<Rc<types::FunctionSignature>>;
     #[salsa::invoke(queries::functions::function_body)]
     fn function_body(&self, id: FunctionId) -> Analysis<Rc<FunctionBody>>;
     #[salsa::cycle(queries::functions::function_dependency_graph_cycle)]
@@ -161,6 +167,16 @@ pub trait AnalyzerDb: SourceDb + Upcast<dyn SourceDb> + UpcastMut<dyn SourceDb>
     // Trait
     #[salsa::invoke(queries::traits::trait_type)]
     fn trait_type(&self, id: TraitId) -> Rc<types::Trait>;
+    #[salsa::invoke(queries::traits::trait_all_functions)]
+    fn trait_all_functions(&self, id: TraitId) -> Rc<[FunctionSigId]>;
+    #[salsa::invoke(queries::traits::trait_function_map)]
+    fn trait_function_map(&self, id: TraitId) -> Analysis<Rc<IndexMap<SmolStr, FunctionSigId>>>;
+
+    // Impl
+    #[salsa::invoke(queries::impls::impl_all_functions)]
+    fn impl_all_functions(&self, id: ImplId) -> Rc<[FunctionId]>;
+    #[salsa::invoke(queries::impls::impl_function_map)]
+    fn impl_function_map(&self, id: ImplId) -> Analysis<Rc<IndexMap<SmolStr, FunctionId>>>;
 
     // Event
     #[salsa::invoke(queries::events::event_type)]

crates/analyzer/src/db/queries.rs

@@ -1,6 +1,7 @@
 pub mod contracts;
 pub mod events;
 pub mod functions;
+pub mod impls;
 pub mod ingots;
 pub mod module;
 pub mod structs;

crates/analyzer/src/db/queries/contracts.rs

@@ -22,13 +22,9 @@ pub fn contract_all_functions(db: &dyn AnalyzerDb, contract: ContractId) -> Rc<[
     body.iter()
         .filter_map(|stmt| match stmt {
             ast::ContractStmt::Event(_) => None,
-            ast::ContractStmt::Function(node) => {
-                Some(db.intern_function(Rc::new(items::Function {
-                    ast: node.clone(),
-                    module,
-                    parent: Some(items::Class::Contract(contract)),
-                })))
-            }
+            ast::ContractStmt::Function(node) => Some(db.intern_function(Rc::new(
+                items::Function::new(db, node, Some(items::Class::Contract(contract)), module),
+            ))),
         })
         .collect()
 }
@@ -53,7 +49,7 @@ pub fn contract_function_map(
                 def_name,
                 &NamedThing::Item(Item::Event(event)),
                 Some(event.name_span(db)),
-                def.kind.name.span,
+                def.kind.sig.kind.name.span,
             );
             continue;
         }
@@ -64,7 +60,7 @@ pub fn contract_function_map(
                 def_name,
                 &named_item,
                 named_item.name_span(db),
-                def.kind.name.span,
+                def.kind.sig.kind.name.span,
             );
             continue;
         }
@@ -334,6 +330,14 @@ pub fn contract_field_type(
 
     let node = &field.data(db).ast;
 
+    if let Ok(Type::Trait(ref val)) = typ {
+        scope.error(
+            "traits can not be used as contract fields",
+            node.span,
+            &format!("trait `{}` can not appear here", val.name),
+        );
+    }
+
     if node.kind.is_pub {
         scope.not_yet_implemented("contract `pub` fields", node.span);
     }

crates/analyzer/src/db/queries/functions.rs

@@ -2,27 +2,27 @@ use crate::context::{AnalyzerContext, CallType, FunctionBody};
 use crate::db::{Analysis, AnalyzerDb};
 use crate::errors::TypeError;
 use crate::namespace::items::{
-    Class, DepGraph, DepGraphWrapper, DepLocality, FunctionId, Item, TypeDef,
+    Class, DepGraph, DepGraphWrapper, DepLocality, FunctionId, FunctionSigId, Item, TypeDef,
 };
 use crate::namespace::scopes::{BlockScope, BlockScopeType, FunctionScope, ItemScope};
 use crate::namespace::types::{self, Contract, CtxDecl, Generic, SelfDecl, Struct, Type};
 use crate::traversal::functions::traverse_statements;
 use crate::traversal::types::type_desc;
 use fe_common::diagnostics::Label;
-use fe_parser::ast;
+use fe_parser::ast::{self, GenericParameter};
 use fe_parser::node::Node;
 use if_chain::if_chain;
+use smol_str::SmolStr;
 use std::collections::HashMap;
 use std::rc::Rc;
 
 /// Gather context information for a function definition and check for type
 /// errors. Does not inspect the function body.
 pub fn function_signature(
     db: &dyn AnalyzerDb,
-    function: FunctionId,
+    function: FunctionSigId,
 ) -> Analysis<Rc<types::FunctionSignature>> {
-    let node = &function.data(db).ast;
-    let def = &node.kind;
+    let def = &function.data(db).ast;
 
     let mut scope = ItemScope::new(db, function.module(db));
     let fn_parent = function.class(db);
@@ -32,9 +32,27 @@ pub fn function_signature(
     let mut names = HashMap::new();
     let mut labels = HashMap::new();
 
-    if let (Some(Class::Contract(_)), true) = (fn_parent, function.is_generic(db)) {
+    function.data(db).ast.kind.generic_params.kind.iter().fold(
+        HashMap::<SmolStr, Node<_>>::new(),
+        |mut accum, param| {
+            if let Some(previous) = accum.get(&param.name()) {
+                scope.duplicate_name_error(
+                    "duplicate generic parameter",
+                    &param.name(),
+                    previous.span,
+                    param.name_node().span,
+                );
+            } else {
+                accum.insert(param.name(), param.name_node());
+            };
+
+            accum
+        },
+    );
+
+    if !matches!(fn_parent, Some(Class::Struct(_))) && function.is_generic(db) {
         scope.fancy_error(
-            "generic function parameters aren't yet supported in contract functions",
+            "generic function parameters aren't yet supported outside of struct functions",
             vec![Label::primary(
                 function.data(db).ast.kind.generic_params.span,
                 "This can not appear here",
@@ -43,7 +61,26 @@ pub fn function_signature(
         );
     }
 
+    if function.is_generic(db) {
+        for param in function.data(db).ast.kind.generic_params.kind.iter() {
+            if let GenericParameter::Unbounded(val) = param {
+                scope.fancy_error(
+                    "unbounded generic parameters aren't yet supported",
+                    vec![Label::primary(
+                        val.span,
+                        format!("`{}` needs to be bound by some trait", val.kind),
+                    )],
+                    vec![format!(
+                        "Hint: Change `{}` to `{}: SomeTrait`",
+                        val.kind, val.kind
+                    )],
+                );
+            }
+        }
+    }
+
     let params = def
+        .kind
         .args
         .iter()
         .enumerate()
@@ -73,7 +110,7 @@ pub fn function_signature(
                     _ => Err(TypeError::new(scope.error(
                         "function parameter types must have fixed size",
                         reg.typ.span,
-                        "`Map` type can't be used as a function parameter",
+                        &format!("`{}` type can't be used as a function parameter", typ.name()),
                     ))),
                 });
 
@@ -114,9 +151,9 @@ pub fn function_signature(
                         if label.kind != "_";
                         if let Some(dup_idx) = labels.get(&label.kind);
                         then {
-                            let dup_arg: &Node<ast::FunctionArg> = &def.args[*dup_idx];
+                            let dup_arg: &Node<ast::FunctionArg> = &def.kind.args[*dup_idx];
                             scope.fancy_error(
-                                &format!("duplicate parameter labels in function `{}`", def.name.kind),
+                                &format!("duplicate parameter labels in function `{}`", def.kind.name.kind),
                                 vec![
                                     Label::primary(dup_arg.span, "the label `{}` was first used here"),
                                     Label::primary(label.span, "label `{}` used again here"),
@@ -138,9 +175,9 @@ pub fn function_signature(
                     );
                     None
                 } else if let Some(dup_idx) = names.get(&reg.name.kind) {
-                    let dup_arg: &Node<ast::FunctionArg> = &def.args[*dup_idx];
+                    let dup_arg: &Node<ast::FunctionArg> = &def.kind.args[*dup_idx];
                     scope.duplicate_name_error(
-                        &format!("duplicate parameter names in function `{}`", def.name.kind),
+                        &format!("duplicate parameter names in function `{}`", function.name(db)),
                         &reg.name.kind,
                         dup_arg.span,
                         arg.span,
@@ -159,10 +196,11 @@ pub fn function_signature(
         .collect();
 
     let return_type = def
+        .kind
         .return_type
         .as_ref()
         .map(|type_node| {
-            let fn_name = &def.name.kind;
+            let fn_name = &function.name(db);
             if fn_name == "__init__" || fn_name == "__call__" {
                 // `__init__` and `__call__` must not return any type other than `()`.
                 if type_node.kind != ast::TypeDesc::Unit {
@@ -207,7 +245,7 @@ pub fn function_signature(
 
 pub fn resolve_function_param_type(
     db: &dyn AnalyzerDb,
-    function: FunctionId,
+    function: FunctionSigId,
     context: &mut dyn AnalyzerContext,
     desc: &Node<ast::TypeDesc>,
 ) -> Result<Type, TypeError> {
@@ -254,11 +292,11 @@ pub fn function_body(db: &dyn AnalyzerDb, function: FunctionId) -> Analysis<Rc<F
                 "function body is missing a return or revert statement",
                 vec![
                     Label::primary(
-                        def.name.span,
+                        function.name_span(db),
                         "all paths of this function must `return` or `revert`",
                     ),
                     Label::secondary(
-                        def.return_type.as_ref().unwrap().span,
+                        def.sig.kind.return_type.as_ref().unwrap().span,
                         format!("expected function to return `{}`", return_type),
                     ),
                 ],
@@ -362,6 +400,13 @@ pub fn function_dependency_graph(db: &dyn AnalyzerDb, function: FunctionId) -> D
                 directs.push((root, class.as_item(), DepLocality::Local));
                 directs.push((root, Item::Function(*method), DepLocality::Local));
             }
+            CallType::TraitValueMethod { trait_id, .. } => {
+                directs.push((
+                    root,
+                    Item::Type(TypeDef::Trait(*trait_id)),
+                    DepLocality::Local,
+                ));
+            }
             CallType::External { contract, function } => {
                 directs.push((root, Item::Function(*function), DepLocality::External));
                 // Probably redundant: