fix(checker): change some diagnostics to warnings

temporarily change type errors in predicates to warnings until operations are fully type checked

midas/checker/midas.py

@@ -31,7 +31,7 @@ class TypedParamSpec:
     kw: list[Function.Argument]
 
 
-class MidasTyper(m.Stmt.Visitor[None], m.Expr.Visitor[None], m.Type.Visitor[Type]):
+class MidasTyper(m.Stmt.Visitor[None], m.Expr.Visitor[Type], m.Type.Visitor[Type]):
     """A resolver which evaluates Midas type definitions and build a registry"""
 
     def __init__(self, types: TypesRegistry, reporter: Reporter) -> None:
@@ -41,6 +41,8 @@ class MidasTyper(m.Stmt.Visitor[None], m.Expr.Visitor[None], m.Type.Visitor[Type
         self.types: TypesRegistry = types
         self._local_variables: dict[str, TypeVar] = {}
 
+        self._predicate_params: dict[str, Type] = {}
+
         self._current_name: Optional[str] = None
 
         define_builtins(self.types)
@@ -59,6 +61,10 @@ class MidasTyper(m.Stmt.Visitor[None], m.Expr.Visitor[None], m.Type.Visitor[Type
             self.reporter.error(error.token.get_location(), error.message)
         self.resolve(stmts)
 
+    def type_of(self, expr: m.Expr) -> Type:
+        type: Type = expr.accept(self)
+        return type
+
     def get_type(self, name: str) -> Type:
         """Get a type from its name
 
@@ -75,6 +81,14 @@ class MidasTyper(m.Stmt.Visitor[None], m.Expr.Visitor[None], m.Type.Visitor[Type
             return self._local_variables[name]
         return self.types.get_type(name)
 
+    def get_variable(self, name: str) -> Type:
+        if name in self._predicate_params:
+            return self._predicate_params[name]
+        predicate: Optional[Predicate] = self.types.lookup_predicate(name)
+        if predicate is None:
+            raise NameError(f"Unknown variable '{name}'")
+        return predicate.type
+
     def resolve(self, stmts: list[m.Stmt]):
         """Process a sequence of statements
 
@@ -84,6 +98,12 @@ class MidasTyper(m.Stmt.Visitor[None], m.Expr.Visitor[None], m.Type.Visitor[Type
         for stmt in stmts:
             stmt.accept(self)
 
+    def assert_bool(self, expr: m.Expr):
+        type: Type = self.type_of(expr)
+        if not self.types.is_subtype(type, self._bool):
+            # TODO: change back to error when operations are type checked
+            self.reporter.warning(expr.location, f"Must be a boolean but is {type}")
+
     def visit_type_stmt(self, stmt: m.TypeStmt) -> None:
         name: str = stmt.name.lexeme
         self._current_name = name
@@ -118,51 +138,125 @@ class MidasTyper(m.Stmt.Visitor[None], m.Expr.Visitor[None], m.Type.Visitor[Type
             )
 
     def visit_predicate_stmt(self, stmt: m.PredicateStmt) -> None:
+        for spec in stmt.params:
+            for param in spec.mixed:
+                assert param.name is not None
+                self._predicate_params[param.name.lexeme] = param.type.accept(self)
+
+        type: Type = self.type_of(stmt.body)
         params: list[TypedParamSpec] = [
             self._visit_param_spec(spec) for spec in stmt.params
         ]
-        type: Type = self._bool
-        for spec in reversed(params):
-            type = Function(
-                pos_args=spec.pos,
-                args=spec.mixed,
-                kw_args=spec.kw,
-                returns=type,
+
+        if not self._is_valid_predicate(type):
+            # TODO: change back to error when operations are type checked
+            self.reporter.warning(
+                stmt.body.location,
+                f"Predicate function body must evaluate to a boolean, got {type}",
             )
+        if len(params) != 0:
+            type = self._bool
+            for spec in reversed(params):
+                type = Function(
+                    pos_args=spec.pos,
+                    args=spec.mixed,
+                    kw_args=spec.kw,
+                    returns=type,
+                )
+        self._predicate_params = {}
         self.types.define_predicate(
             stmt.name.lexeme,
             Predicate(
                 type=type,
                 body=stmt.body,
+                alias=len(params) == 0,
             ),
         )
 
-    def visit_logical_expr(self, expr: m.LogicalExpr) -> None:
-        self.reporter.warning(expr.location, "LogicalExpr not yet supported")
+    def _is_valid_predicate(self, body: Type) -> bool:
+        match body:
+            case Function(returns=returns):
+                return self._is_valid_predicate(returns)
+            case _ if self.types.is_subtype(body, self._bool):
+                return True
+            case _:
+                return False
 
-    def visit_binary_expr(self, expr: m.BinaryExpr) -> None:
+    def visit_logical_expr(self, expr: m.LogicalExpr) -> Type:
+        self.assert_bool(expr.left)
+        self.assert_bool(expr.right)
+        return self._bool
+
+    def visit_binary_expr(self, expr: m.BinaryExpr) -> Type:
+        # TODO
         self.reporter.warning(expr.location, "BinaryExpr not yet supported")
+        return UnknownType()
 
-    def visit_unary_expr(self, expr: m.UnaryExpr) -> None:
+    def visit_unary_expr(self, expr: m.UnaryExpr) -> Type:
+        # TODO
         self.reporter.warning(expr.location, "UnaryExpr not yet supported")
+        return UnknownType()
 
-    def visit_call_expr(self, expr: m.CallExpr) -> None:
-        self.reporter.warning(expr.location, "CallExpr not yet supported")
+    def visit_call_expr(self, expr: m.CallExpr) -> Type:
+        callee: Type = expr.callee.accept(self)
+        if not isinstance(callee, Function):
+            self.reporter.error(expr.location, f"Cannot call {callee}")
+            return UnknownType()
+        args: list[Type] = [arg.accept(self) for arg in expr.arguments]
 
-    def visit_get_expr(self, expr: m.GetExpr) -> None:
-        self.reporter.warning(expr.location, "GetExpr not yet supported")
+        n_args: int = len(args)
+        n_params: int = len(callee.args)
+        if n_args != n_params:
+            self.reporter.error(
+                expr.location,
+                f"Wrong number of argument, expected {n_params}, got {n_args}",
+            )
+            return UnknownType()
 
-    def visit_variable_expr(self, expr: m.VariableExpr) -> None:
-        self.reporter.warning(expr.location, "VariableExpr not yet supported")
+        valid: bool = True
+        for arg, param in zip(args, callee.args):
+            if not self.types.is_subtype(arg, param.type):
+                self.reporter.error(
+                    expr.location,
+                    f"Invalid argument type at pos {param.pos}, expected {param.type}, got {arg}",
+                )
+                valid = False
+        if not valid:
+            return UnknownType()
+        return callee.returns
 
-    def visit_grouping_expr(self, expr: m.GroupingExpr) -> None:
+    def visit_get_expr(self, expr: m.GetExpr) -> Type:
+        object: Type = expr.expr.accept(self)
+        member: Optional[Type] = self.types.lookup_member(object, expr.name.lexeme)
+        if member is None:
+            self.reporter.error(
+                expr.location, f"Unknown member '{expr.name}' of {object}"
+            )
+            return UnknownType()
+        return member
+
+    def visit_variable_expr(self, expr: m.VariableExpr) -> Type:
+        return self.get_variable(expr.name.lexeme)
+
+    def visit_grouping_expr(self, expr: m.GroupingExpr) -> Type:
         return expr.expr.accept(self)
 
-    def visit_literal_expr(self, expr: m.LiteralExpr) -> None:
-        self.reporter.warning(expr.location, "LiteralExpr not yet supported")
+    def visit_literal_expr(self, expr: m.LiteralExpr) -> Type:
+        match expr.value:
+            case bool():  # Must be before int
+                return self.types.get_type("bool")
+            case int():
+                return self.types.get_type("int")
+            case float():
+                return self.types.get_type("float")
+            case str():
+                return self.types.get_type("str")
+            case _:
+                self.reporter.warning(expr.location, f"Unknown literal {expr}")
+                return UnknownType()
 
-    def visit_wildcard_expr(self, expr: m.WildcardExpr) -> None:
-        self.reporter.warning(expr.location, "WildcardExpr not yet supported")
+    def visit_wildcard_expr(self, expr: m.WildcardExpr) -> Type:
+        return self.get_variable("_")
 
     def visit_named_type(self, type: m.NamedType) -> Type:
         name: str = type.name.lexeme

midas/checker/python.py

@@ -652,7 +652,7 @@ class PythonTyper(
         If the function has overloads, the function will try to resolve the
         appropriate signature.
         Argument types are matched to the defined parameters.
-        The function doesn't take the raw expression as a parameter to accomodate
+        The function doesn't take the raw expression as a parameter to accommodate
         for desugared calls such as for operators.
 
         Args:

midas/checker/registry.py

@@ -7,6 +7,7 @@ from midas.checker.types import (
     AppliedType,
     BaseType,
     ComplexType,
+    ConstraintType,
     ExtensionType,
     Function,
     GenericType,
@@ -130,6 +131,9 @@ class TypesRegistry:
                     return False
                 return self.is_subtype(bound, type2)
 
+            case (ConstraintType(type=base1), _):
+                return self.is_subtype(base1, type2)
+
         return False
 
     # TODO: verify the logic in here

midas/checker/types.py

@@ -238,10 +238,63 @@ def unfold_type(type: Type) -> Type:
             return type
 
 
+def to_annotation(type: Type) -> str:
+    def _args_annotation(func: Function) -> str:
+        if len(func.kw_args) != 0:
+            return "..."
+
+        args: str = ", ".join(
+            to_annotation(arg.type) for arg in func.pos_args + func.args
+        )
+        return f"[{args}]"
+
+    match type:
+        case TopType():
+            return "Any"
+
+        case BaseType(name=name):
+            return name
+
+        case AliasType(name=name):
+            return name
+
+        case UnknownType():
+            return "Any"
+
+        case UnitType():
+            return "None"
+
+        case Function(returns=returns):
+            params_annot: str = _args_annotation(type)
+            return f"Callable[{params_annot}, {to_annotation(returns)}]"
+
+        case OverloadedFunction():
+            return "Callable"
+
+        case ComplexType() | ExtensionType():
+            raise NotImplementedError
+
+        case TypeVar(name=name):
+            return name
+
+        case GenericType(name=name, params=params):
+            return f"{name}[{', '.join(map(to_annotation, params))}]"
+
+        case AppliedType(name=name, args=args):
+            return f"{name}[{', '.join(map(to_annotation, args))}]"
+
+        case ConstraintType():
+            return str(type)
+
+        case _:
+            assert_never(type)
+
+
 @dataclass(frozen=True, kw_only=True)
 class Predicate:
     type: Type
     body: m.Expr
+    alias: bool
 
 
 Type = (

midas/generator/constraints.py

@@ -3,7 +3,12 @@ from typing import Optional
 
 import midas.ast.midas as m
 from midas.checker.registry import TypesRegistry
-from midas.checker.types import Function, Predicate, Type
+from midas.checker.types import (
+    Function,
+    Predicate,
+    Type,
+    to_annotation,
+)
 from midas.lexer.token import TokenType
 
 LOGICAL_OPERATORS: dict[TokenType, type[ast.boolop]] = {
@@ -63,26 +68,55 @@ class ConstraintGenerator(m.Expr.Visitor[ast.expr]):
                 )
                 alias: str = self.make_alias(None)
                 definition: ast.stmt = self.make_definition(
-                    alias, Predicate(type=func, body=expr)
+                    alias, Predicate(type=func, body=expr, alias=False)
                 )
                 self._definitions.append(definition)
                 return ast.Name(id=alias)
 
     def make_alias(self, name: Optional[str]) -> str:
-        suffix: str = f"_{name}" if name is not None else ""
-        alias: str = f"__midas_p{self._id}{suffix}__"
-        self._id += 1
+        suffix: str
+        if name is None:
+            suffix = f"p{self._id}"
+            self._id += 1
+        else:
+            suffix = name
+        alias: str = f"__midas_{suffix}__"
         return alias
 
     def make_definition(self, name: str, predicate: Predicate) -> ast.stmt:
-        body: list[ast.stmt] = [ast.Return(value=predicate.body.accept(self))]
-        return self.make_func(name, body, predicate.type)
+        body: ast.expr = predicate.body.accept(self)
+        if predicate.alias:
+            return ast.Assign(
+                targets=[
+                    ast.Name(id=name),
+                ],
+                value=body,
+            )
+        return self.make_func(name, [ast.Return(value=body)], predicate.type)
 
     def make_args(self, func: Function) -> ast.arguments:
         return ast.arguments(
-            posonlyargs=[ast.arg(arg=arg.name) for arg in func.pos_args],
-            args=[ast.arg(arg=arg.name) for arg in func.args],
-            kwonlyargs=[ast.arg(arg=arg.name) for arg in func.kw_args],
+            posonlyargs=[
+                ast.arg(
+                    arg=arg.name,
+                    annotation=ast.Constant(value=to_annotation(arg.type)),
+                )
+                for arg in func.pos_args
+            ],
+            args=[
+                ast.arg(
+                    arg=arg.name,
+                    annotation=ast.Constant(value=to_annotation(arg.type)),
+                )
+                for arg in func.args
+            ],
+            kwonlyargs=[
+                ast.arg(
+                    arg=arg.name,
+                    annotation=ast.Constant(value=to_annotation(arg.type)),
+                )
+                for arg in func.kw_args
+            ],
             defaults=[],
             kw_defaults=[],
         )
@@ -100,6 +134,7 @@ class ConstraintGenerator(m.Expr.Visitor[ast.expr]):
                         self.make_func(inner_name, inner_body, type.returns, level + 1),
                         ast.Return(value=ast.Name(id=inner_name)),
                     ],
+                    returns=ast.Constant(value=to_annotation(type.returns)),
                     decorator_list=[],
                 )
 
@@ -108,11 +143,12 @@ class ConstraintGenerator(m.Expr.Visitor[ast.expr]):
                     name=name,
                     args=self.make_args(type),
                     body=inner_body,
+                    returns=ast.Constant(value=to_annotation(type.returns)),
                     decorator_list=[],
                 )
 
             case _:
-                raise ValueError(f"Expected function, got {type}")
+                raise ValueError(f"Expected function, got {type!r}")
 
     def get_predicate(self, name: str) -> Optional[ast.expr]:
         if name not in self._aliases:

midas/parser/midas.py

@@ -380,7 +380,7 @@ class MidasParser(Parser):
             TokenType.RIGHT_PAREN, "Expected ')' after arguments."
         )
         return CallExpr(
-            location=l_paren.location_to(r_paren),
+            location=Location.span(callee.location, r_paren.get_location()),
             callee=callee,
             arguments=pos_args,
             keywords=kw_args,