Merge remote-tracking branch 'origin/hm-inference' into hm-inference_anto

nac3core/src/typecheck/type_inferencer/mod.rs

@@ -1,6 +1,6 @@
 use std::cell::RefCell;
 use std::collections::HashMap;
-use std::convert::TryInto;
+use std::convert::{TryInto, From};
 use std::iter::once;
 use std::rc::Rc;
 
@@ -17,6 +17,21 @@ use rustpython_parser::ast::{
 #[cfg(test)]
 mod test;
 
+#[derive(PartialEq, Eq, Hash, Copy, Clone, Debug)]
+pub struct CodeLocation {
+    row: usize,
+    col: usize,
+}
+
+impl From<Location> for CodeLocation {
+    fn from(loc: Location) -> CodeLocation {
+        CodeLocation {
+            row: loc.row(),
+            col: loc.column()
+        }
+    }
+}
+
 pub struct PrimitiveStore {
     pub int32: Type,
     pub int64: Type,
@@ -37,6 +52,7 @@ pub struct Inferencer<'a> {
     pub primitives: &'a PrimitiveStore,
     pub virtual_checks: &'a mut Vec<(Type, Type)>,
     pub variable_mapping: HashMap<String, Type>,
+    pub calls: &'a mut HashMap<CodeLocation, Rc<Call>>,
 }
 
 struct NaiveFolder();
@@ -215,6 +231,7 @@ impl<'a> Inferencer<'a> {
             unifier: self.unifier,
             primitives: self.primitives,
             virtual_checks: self.virtual_checks,
+            calls: self.calls,
             variable_mapping,
         };
         let fun = FunSignature {
@@ -257,6 +274,7 @@ impl<'a> Inferencer<'a> {
             virtual_checks: self.virtual_checks,
             variable_mapping,
             primitives: self.primitives,
+            calls: self.calls,
         };
         let elt = new_context.fold_expr(elt)?;
         let generator = generators.pop().unwrap();
@@ -379,6 +397,7 @@ impl<'a> Inferencer<'a> {
             fun: RefCell::new(None),
             ret,
         });
+        self.calls.insert(location.into(), call.clone());
         let call = self.unifier.add_ty(TypeEnum::TCall(vec![call].into()));
         self.unifier.unify(func.custom.unwrap(), call)?;
 

nac3core/src/typecheck/type_inferencer/test.rs

@@ -42,6 +42,7 @@ struct TestEnvironment {
     pub id_to_name: HashMap<usize, String>,
     pub identifier_mapping: HashMap<String, Type>,
     pub virtual_checks: Vec<(Type, Type)>,
+    pub calls: HashMap<CodeLocation, Rc<Call>>,
 }
 
 impl TestEnvironment {
@@ -218,12 +219,13 @@ impl TestEnvironment {
             function_data: FunctionData {
                 resolver,
                 bound_variables: Vec::new(),
-                return_type: None
+                return_type: None,
             },
             primitives,
             id_to_name,
             identifier_mapping,
             virtual_checks: Vec::new(),
+            calls: HashMap::new(),
         }
     }
 
@@ -234,6 +236,7 @@ impl TestEnvironment {
             variable_mapping: Default::default(),
             primitives: &mut self.primitives,
             virtual_checks: &mut self.virtual_checks,
+            calls: &mut self.calls,
         }
     }
 }

nac3core/src/typecheck/typedef/mod.rs

@@ -47,6 +47,9 @@ pub enum TypeVarMeta {
 
 #[derive(Clone)]
 pub enum TypeEnum {
+    TRigidVar {
+        id: u32,
+    },
     TVar {
         id: u32,
         meta: TypeVarMeta,
@@ -74,6 +77,7 @@ pub enum TypeEnum {
 impl TypeEnum {
     pub fn get_type_name(&self) -> &'static str {
         match self {
+            TypeEnum::TRigidVar { .. } => "TRigidVar",
             TypeEnum::TVar { .. } => "TVar",
             TypeEnum::TTuple { .. } => "TTuple",
             TypeEnum::TList { .. } => "TList",
@@ -127,6 +131,12 @@ impl Unifier {
         self.unification_table.probe_value(a).clone()
     }
 
+    pub fn get_fresh_rigid_var(&mut self) -> (Type, u32) {
+        let id = self.var_id + 1;
+        self.var_id += 1;
+        (self.add_ty(TypeEnum::TRigidVar { id }), id)
+    }
+
     pub fn get_fresh_var(&mut self) -> (Type, u32) {
         self.get_fresh_var_with_range(&[])
     }
@@ -139,9 +149,17 @@ impl Unifier {
         (self.add_ty(TypeEnum::TVar { id, range, meta: TypeVarMeta::Generic }), id)
     }
 
+    /// Unification would not unify rigid variables with other types, but we want to do this for
+    /// function instantiations, so we make it explicit.
+    pub fn replace_rigid_var(&mut self, rigid: Type, b: Type) {
+        assert!(matches!(&*self.get_ty(rigid), TypeEnum::TRigidVar { .. }));
+        self.set_a_to_b(rigid, b);
+    }
+
     pub fn is_concrete(&mut self, a: Type, allowed_typevars: &[Type]) -> bool {
         use TypeEnum::*;
         match &*self.get_ty(a) {
+            TRigidVar { .. } => true,
             TVar { .. } => allowed_typevars.iter().any(|b| self.unification_table.unioned(a, *b)),
             TCall { .. } => false,
             TList { ty } => self.is_concrete(*ty, allowed_typevars),
@@ -290,11 +308,8 @@ impl Unifier {
             (TVar { meta: Record(map), id, range, .. }, TObj { fields, .. }) => {
                 self.occur_check(a, b)?;
                 for (k, v) in map.borrow().iter() {
-                    if let Some(ty) = fields.get(k) {
+                    let ty = fields.get(k).ok_or_else(|| format!("No such attribute {}", k))?;
                     self.unify(*ty, *v)?;
-                    } else {
-                        return Err(format!("No such attribute {}", k));
-                    }
                 }
                 let x = self.check_var_compatibility(*id, b, &range.borrow())?.unwrap_or(b);
                 self.unify(x, b)?;
@@ -305,14 +320,11 @@ impl Unifier {
                 let ty = self.get_ty(*ty);
                 if let TObj { fields, .. } = ty.as_ref() {
                     for (k, v) in map.borrow().iter() {
-                        if let Some(ty) = fields.get(k) {
+                        let ty = fields.get(k).ok_or_else(|| format!("No such attribute {}", k))?;
                         if !matches!(self.get_ty(*ty).as_ref(), TFunc { .. }) {
                             return Err(format!("Cannot access field {} for virtual type", k));
                         }
                         self.unify(*v, *ty)?;
-                        } else {
-                            return Err(format!("No such attribute {}", k));
-                        }
                     }
                 } else {
                     // require annotation...
@@ -382,11 +394,11 @@ impl Unifier {
                         if let Some(i) = required.iter().position(|v| v == k) {
                             required.remove(i);
                         }
-                        if let Some(i) = all_names.iter().position(|v| &v.0 == k) {
+                        let i = all_names
+                            .iter()
+                            .position(|v| &v.0 == k)
+                            .ok_or_else(|| format!("Unknown keyword argument {}", k))?;
                         self.unify(all_names.remove(i).1, *t)?;
-                        } else {
-                            return Err(format!("Unknown keyword argument {}", k));
-                        }
                     }
                     if !required.is_empty() {
                         return Err("Expected more arguments".to_string());
@@ -435,6 +447,7 @@ impl Unifier {
         use TypeVarMeta::*;
         let ty = self.unification_table.probe_value(ty).clone();
         match ty.as_ref() {
+            TypeEnum::TRigidVar { id } => var_to_name(*id),
             TypeEnum::TVar { id, meta: Generic, .. } => var_to_name(*id),
             TypeEnum::TVar { meta: Sequence(map), .. } => {
                 let fields = map
@@ -544,6 +557,7 @@ impl Unifier {
         // variables, i.e. things like TRecord, TCall should not occur, and we
         // should be safe to not implement the substitution for those variants.
         match &*ty {
+            TypeEnum::TRigidVar { .. } => None,
             TypeEnum::TVar { id, meta: Generic, .. } => mapping.get(&id).cloned(),
             TypeEnum::TTuple { ty } => {
                 let mut new_ty = Cow::from(ty);
@@ -634,7 +648,7 @@ impl Unifier {
         let ty = self.unification_table.probe_value(b).clone();
 
         match ty.as_ref() {
-            TypeEnum::TVar { meta: Generic, .. } => {}
+            TypeEnum::TRigidVar { .. } | TypeEnum::TVar { meta: Generic, .. } => {}
             TypeEnum::TVar { meta: Sequence(map), .. } => {
                 for t in map.borrow().values() {
                     self.occur_check(a, *t)?;

nac3core/src/typecheck/typedef/test.rs

@@ -451,3 +451,25 @@ fn test_typevar_range() {
         Err("Cannot unify type variable 21 with TObj due to incompatible value range".into())
     );
 }
+
+#[test]
+fn test_rigid_var() {
+    let mut env = TestEnvironment::new();
+    let a = env.unifier.get_fresh_rigid_var().0;
+    let b = env.unifier.get_fresh_rigid_var().0;
+    let x = env.unifier.get_fresh_var().0;
+    let list_a = env.unifier.add_ty(TypeEnum::TList { ty: a });
+    let list_x = env.unifier.add_ty(TypeEnum::TList { ty: x });
+    let int = env.parse("int", &HashMap::new());
+    let list_int = env.parse("List[int]", &HashMap::new());
+
+    assert_eq!(env.unifier.unify(a, b), Err("Cannot unify TRigidVar with TRigidVar".to_string()));
+    env.unifier.unify(list_a, list_x).unwrap();
+    assert_eq!(
+        env.unifier.unify(list_x, list_int),
+        Err("Cannot unify TObj with TRigidVar".to_string())
+    );
+
+    env.unifier.replace_rigid_var(a, int);
+    env.unifier.unify(list_x, list_int).unwrap();
+}