Perform runtime type checks

Author: JukkaL

mypyc/codegen/emit.py

@@ -705,13 +705,25 @@ def emit_cast(
             self.emit_lines(f"    {dest} = {src};", "else {")
             self.emit_cast_error_handler(error, src, dest, typ, raise_exception)
             self.emit_line("}")
-        elif is_object_rprimitive(typ) or is_native_rprimitive(typ):
+        elif is_object_rprimitive(typ):
             if declare_dest:
                 self.emit_line(f"PyObject *{dest};")
             self.emit_arg_check(src, dest, typ, "", optional)
             self.emit_line(f"{dest} = {src};")
             if optional:
                 self.emit_line("}")
+        elif is_native_rprimitive(typ):
+            # Native primitive types have type check functions of form "CPy<Name>_Check(...)".
+            if declare_dest:
+                self.emit_line(f"PyObject *{dest};")
+            short_name = typ.name.rsplit(".", 1)[-1]
+            check = f"(CPy{short_name}_Check({src}))"
+            if likely:
+                check = f"(likely{check})"
+            self.emit_arg_check(src, dest, typ, check, optional)
+            self.emit_lines(f"    {dest} = {src};", "else {")
+            self.emit_cast_error_handler(error, src, dest, typ, raise_exception)
+            self.emit_line("}")
         elif isinstance(typ, RUnion):
             self.emit_union_cast(
                 src, dest, typ, declare_dest, error, optional, src_type, raise_exception

mypyc/test-data/run-classes.test

@@ -2713,7 +2713,7 @@ Player.MIN = <Player.MIN: 1>
 [case testBufferRoundTrip_librt_internal]
 from __future__ import annotations
 
-from typing import Final
+from typing import Final, Any
 from mypy_extensions import u8
 from librt.internal import (
     ReadBuffer, WriteBuffer, write_bool, read_bool, write_str, read_str, write_float, read_float,
@@ -2746,6 +2746,23 @@ def test_buffer_grow() -> None:
     with assertRaises(ValueError):
         read_int(r)
 
+def test_buffer_primitive_types() -> None:
+    a1: Any = WriteBuffer()
+    w: WriteBuffer = a1
+    write_str(w, "foo")
+    data = w.getvalue()
+    assert read_str(ReadBuffer(data)) == "foo"
+    a2: Any = ReadBuffer(b"foo")
+    with assertRaises(TypeError):
+        w2: WriteBuffer = a2
+
+    a3: Any = ReadBuffer(data)
+    r: ReadBuffer = a3
+    assert read_str(r) == "foo"
+    a4: Any = WriteBuffer()
+    with assertRaises(TypeError):
+        r2: ReadBuffer = a4
+
 def test_buffer_roundtrip() -> None:
     b: WriteBuffer | ReadBuffer
     b = WriteBuffer()