Merge remote-tracking branch 'origin/main' into feat/py2

.github/workflows/pull-request.yaml

@@ -26,6 +26,7 @@ jobs:
         with:
           command: build
           sccache: 'true'
+          rust-toolchain: '1.75'
           working-directory: validator
 
       - name: Install Hugr validator

guppy/checker/core.py

@@ -9,6 +9,7 @@
     FunctionType,
     GuppyType,
     NoneType,
+    Subst,
     SumType,
     TupleType,
 )
@@ -33,7 +34,7 @@ class CallableVariable(ABC, Variable):
     @abstractmethod
     def check_call(
         self, args: list[ast.expr], ty: GuppyType, node: AstNode, ctx: "Context"
-    ) -> ast.expr:
+    ) -> tuple[ast.expr, Subst]:
         """Checks the return type of a function call against a given type."""
 
     @abstractmethod
@@ -43,6 +44,14 @@ def synthesize_call(
         """Synthesizes the return type of a function call."""
 
 
+@dataclass
+class TypeVarDecl:
+    """A declared type variable."""
+
+    name: str
+    linear: bool
+
+
 PyScope = dict[str, Any]
 
 
@@ -55,6 +64,7 @@ class Globals(NamedTuple):
 
     values: dict[str, Variable]
     types: dict[str, type[GuppyType]]
+    type_vars: dict[str, TypeVarDecl]
     python_scope: PyScope
 
     @staticmethod
@@ -67,7 +77,7 @@ def default() -> "Globals":
             NoneType.name: NoneType,
             BoolType.name: BoolType,
         }
-        return Globals({}, tys, {})
+        return Globals({}, tys, {}, {})
 
     def get_instance_func(self, ty: GuppyType, name: str) -> CallableVariable | None:
         """Looks up an instance function with a given name for a type.
@@ -85,12 +95,14 @@ def __or__(self, other: "Globals") -> "Globals":
         return Globals(
             self.values | other.values,
             self.types | other.types,
+            self.type_vars | other.type_vars,
             self.python_scope | other.python_scope,
         )
 
     def __ior__(self, other: "Globals") -> "Globals":  # noqa: PYI034
         self.values.update(other.values)
         self.types.update(other.types)
+        self.type_vars.update(other.type_vars)
         return self