Typecheck custom binops

examples/custom_binop.reid

@@ -1,7 +1,7 @@
 // Arithmetic, function calls and imports!
 
-impl binop (lhs: u32) + (rhs: u32) -> u32 {
-
+impl binop (lhs: u16) + (rhs: u32) -> u32 {
+  return (lhs as u32) + rhs;
 }
 
 fn main() -> u32 {

reid/src/ast/mod.rs

@@ -217,6 +217,7 @@ pub struct BinopDefinition {
     pub rhs: (String, Type),
     pub return_ty: Type,
     pub block: Block,
+    pub signature_range: TokenRange,
 }
 
 #[derive(Debug)]

reid/src/ast/parse.rs

@@ -554,7 +554,11 @@ impl Parse for Block {
             statements.push(statement);
         }
         stream.expect(Token::BraceClose)?;
-        Ok(Block(statements, return_stmt, stream.get_range().unwrap()))
+        Ok(Block(
+            statements,
+            return_stmt,
+            stream.get_range_prev().unwrap(),
+        ))
     }
 }
 
@@ -814,6 +818,8 @@ impl Parse for BinopDefinition {
         let rhs_type = stream.parse()?;
         stream.expect(Token::ParenClose)?;
 
+        let signature_range = stream.get_range().unwrap();
+
         stream.expect(Token::Arrow)?;
 
         Ok(BinopDefinition {
@@ -822,6 +828,7 @@ impl Parse for BinopDefinition {
             rhs: (rhs_name, rhs_type),
             return_ty: stream.parse()?,
             block: stream.parse()?,
+            signature_range,
         })
     }
 }

reid/src/ast/process.rs

@@ -104,6 +104,7 @@ impl ast::Module {
                     rhs,
                     return_ty,
                     block,
+                    signature_range,
                 }) => {
                     binops.push(mir::BinopDefinition {
                         lhs: (lhs.0.clone(), lhs.1 .0.into_mir(module_id)),
@@ -111,6 +112,7 @@ impl ast::Module {
                         rhs: (rhs.0.clone(), rhs.1 .0.into_mir(module_id)),
                         return_ty: return_ty.0.into_mir(module_id),
                         block: block.into_mir(module_id),
+                        meta: signature_range.as_meta(module_id),
                     });
                 }
             }

reid/src/mir/fmt.rs

@@ -40,6 +40,9 @@ impl Display for Module {
         for import in &self.imports {
             writeln!(inner_f, "{}", import)?;
         }
+        for binop in &self.binop_defs {
+            writeln!(inner_f, "{}", binop)?;
+        }
         for typedef in &self.typedefs {
             writeln!(inner_f, "{}", typedef)?;
         }
@@ -56,6 +59,17 @@ impl Display for Import {
     }
 }
 
+impl Display for BinopDefinition {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "impl binop ({}: {:#}) {} ({}: {:#}) -> {:#} ",
+            self.lhs.0, self.lhs.1, self.op, self.rhs.0, self.rhs.1, self.return_ty
+        )?;
+        Display::fmt(&self.block, f)
+    }
+}
+
 impl Display for TypeDefinition {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         write!(f, "type {} = ", self.name)?;

reid/src/mir/mod.rs

@@ -372,6 +372,17 @@ pub struct BinopDefinition {
     pub rhs: (String, TypeKind),
     pub return_ty: TypeKind,
     pub block: Block,
+    pub meta: Metadata,
+}
+
+impl BinopDefinition {
+    pub fn block_meta(&self) -> Metadata {
+        self.block.meta
+    }
+
+    pub fn signature(&self) -> Metadata {
+        self.meta
+    }
 }
 
 #[derive(Debug)]

reid/src/mir/typecheck.rs

@@ -132,6 +132,11 @@ impl<'t> Pass for TypeCheck<'t> {
             check_typedefs_for_recursion(&defmap, typedef, HashSet::new(), &mut state);
         }
 
+        for binop in &mut module.binop_defs {
+            let res = binop.typecheck(&self.refs, &mut state.inner());
+            state.ok(res, binop.block_meta());
+        }
+
         for function in &mut module.functions {
             let res = function.typecheck(&self.refs, &mut state.inner());
             state.ok(res, function.block_meta());
@@ -170,6 +175,48 @@ fn check_typedefs_for_recursion<'a, 'b>(
     }
 }
 
+impl BinopDefinition {
+    fn typecheck(
+        &mut self,
+        typerefs: &TypeRefs,
+        state: &mut TypecheckPassState,
+    ) -> Result<TypeKind, ErrorKind> {
+        for param in vec![&self.lhs, &self.rhs] {
+            let param_t = state.or_else(
+                param.1.assert_known(typerefs, state),
+                TypeKind::Vague(Vague::Unknown),
+                self.signature(),
+            );
+            let res = state
+                .scope
+                .variables
+                .set(
+                    param.0.clone(),
+                    ScopeVariable {
+                        ty: param_t.clone(),
+                        mutable: param_t.is_mutable(),
+                    },
+                )
+                .or(Err(ErrorKind::VariableAlreadyDefined(param.0.clone())));
+            state.ok(res, self.signature());
+        }
+
+        let return_type = self.return_ty.clone().assert_known(typerefs, state)?;
+
+        state.scope.return_type_hint = Some(self.return_ty.clone());
+        let inferred = self
+            .block
+            .typecheck(&mut state.inner(), &typerefs, Some(&return_type));
+
+        match inferred {
+            Ok(t) => return_type
+                .collapse_into(&t.1)
+                .or(Err(ErrorKind::ReturnTypeMismatch(return_type, t.1))),
+            Err(e) => Ok(state.or_else(Err(e), return_type, self.block_meta())),
+        }
+    }
+}
+
 impl FunctionDefinition {
     fn typecheck(
         &mut self,

reid/src/mir/typeinference.rs

@@ -12,8 +12,8 @@ use super::{
     pass::{Pass, PassResult, PassState},
     typecheck::{ErrorKind, ErrorTypedefKind},
     typerefs::{ScopeTypeRefs, TypeRef, TypeRefs},
-    Block, CustomTypeKey, ExprKind, Expression, FunctionDefinition, FunctionDefinitionKind,
-    IfExpression, Module, ReturnKind, StmtKind,
+    BinopDefinition, Block, CustomTypeKey, ExprKind, Expression, FunctionDefinition,
+    FunctionDefinitionKind, IfExpression, Module, ReturnKind, StmtKind,
     TypeKind::*,
     VagueType::*,
     WhileStatement,
@@ -55,6 +55,11 @@ impl<'t> Pass for TypeInference<'t> {
             }
         }
 
+        for binop in &mut module.binop_defs {
+            let res = binop.infer_types(&self.refs, &mut state.inner());
+            state.ok(res, binop.block_meta());
+        }
+
         for function in &mut module.functions {
             let res = function.infer_types(&self.refs, &mut state.inner());
             state.ok(res, function.block_meta());
@@ -63,6 +68,56 @@ impl<'t> Pass for TypeInference<'t> {
     }
 }
 
+impl BinopDefinition {
+    fn infer_types(
+        &mut self,
+        type_refs: &TypeRefs,
+        state: &mut TypeInferencePassState,
+    ) -> Result<(), ErrorKind> {
+        let scope_hints = ScopeTypeRefs::from(type_refs);
+
+        let lhs_ty = state.or_else(
+            self.lhs.1.assert_unvague(),
+            Vague(Unknown),
+            self.signature(),
+        );
+        state.ok(
+            scope_hints
+                .new_var(self.lhs.0.clone(), false, &lhs_ty)
+                .or(Err(ErrorKind::VariableAlreadyDefined(self.lhs.0.clone()))),
+            self.signature(),
+        );
+
+        let rhs_ty = state.or_else(
+            self.rhs.1.assert_unvague(),
+            Vague(Unknown),
+            self.signature(),
+        );
+
+        state.ok(
+            scope_hints
+                .new_var(self.rhs.0.clone(), false, &rhs_ty)
+                .or(Err(ErrorKind::VariableAlreadyDefined(self.rhs.0.clone()))),
+            self.signature(),
+        );
+
+        state.scope.return_type_hint = Some(self.return_ty.clone());
+        let ret_res = self.block.infer_types(state, &scope_hints);
+        let (_, mut ret_ty) = state.or_else(
+            ret_res,
+            (
+                ReturnKind::Soft,
+                scope_hints.from_type(&Vague(Unknown)).unwrap(),
+            ),
+            self.block_meta(),
+        );
+
+        ret_ty.narrow(&scope_hints.from_type(&self.return_ty).unwrap());
+
+        Ok(())
+    }
+}
+
 impl FunctionDefinition {
     fn infer_types(
         &mut self,