From 98a726215f322bb1d7cee91f761ea3b286b05bce Mon Sep 17 00:00:00 2001
From: AntennaeVY <joses@mahisoft.com>
Date: Tue, 14 Oct 2025 22:31:51 -0400
Subject: [PATCH 1/2] feat(vscode): add debug configuration for baml-cli and
 build task

---
 .vscode/launch.json | 11 +++++++++++
 .vscode/tasks.json  |  8 ++++++++
 2 files changed, 19 insertions(+)

diff --git a/.vscode/launch.json b/.vscode/launch.json
index 99b7b73cf8..f33c3f49fd 100644
--- a/.vscode/launch.json
+++ b/.vscode/launch.json
@@ -66,6 +66,17 @@
       "outFiles": [
         "${workspaceFolder}/typescript/apps/vscode-ext/dist/__test__/**/*.js"
       ]
+    },
+    {
+      "name": "Debug baml-cli --check (direct)",
+      "type": "lldb",
+      "request": "launch",
+      "program": "${workspaceFolder}/engine/target/debug/baml-cli",
+      "args": ["check", "--from", "../integ-tests/"],
+      "cwd": "${workspaceFolder}/engine",
+      "env": { "RUST_LOG": "baml_cli=debug" },
+      "preLaunchTask": "build baml-cli",
+      "sourceLanguages": ["rust"]
     }
   ],
   "compounds": [
diff --git a/.vscode/tasks.json b/.vscode/tasks.json
index 05773b3f74..06bd75669e 100644
--- a/.vscode/tasks.json
+++ b/.vscode/tasks.json
@@ -77,6 +77,14 @@
           "endsPattern": "."
         }
       }
+    },
+    {
+      "label": "build baml-cli",
+      "type": "shell",
+      "command": "cargo",
+      "args": ["build", "--bin", "baml-cli"],
+      "options": { "cwd": "${workspaceFolder}/engine" },
+      "problemMatcher": ["$rustc"]
     }
   ],
   "inputs": [

From eca275943bc9fe7cf3367fc477081e4bdee3064f Mon Sep 17 00:00:00 2001
From: AntennaeVY <joses@mahisoft.com>
Date: Tue, 14 Oct 2025 22:32:48 -0400
Subject: [PATCH 2/2] feat(typecheck): enhance instanceof type checking with
 support for primitive types and enums

---
 engine/baml-compiler/src/thir/typecheck.rs     | 13 ++++++++++---
 .../baml_src/test-files/vm/expr_funcs.baml     | 18 ++++++++++++++++++
 2 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/engine/baml-compiler/src/thir/typecheck.rs b/engine/baml-compiler/src/thir/typecheck.rs
index fb3a747237..3a819ac8fb 100644
--- a/engine/baml-compiler/src/thir/typecheck.rs
+++ b/engine/baml-compiler/src/thir/typecheck.rs
@@ -17,12 +17,13 @@
 ///
 /// However, the current implementation is simple and ad-hoc, likely wrong
 /// in several places. Bidirectional typing is the target.
-use std::{borrow::Cow, sync::Arc};
+use std::{borrow::Cow, str::FromStr, sync::Arc};
 
 use baml_types::{
     ir_type::{ArrowGeneric, TypeIR},
     BamlMap, BamlMediaType, BamlValueWithMeta, TypeValue,
 };
+use baml_vm::types::Type;
 use internal_baml_ast::ast::WithSpan;
 use internal_baml_diagnostics::{DatamodelError, Diagnostics, Span};
 
@@ -1371,6 +1372,7 @@ pub fn typecheck_expression(
                     "image" | "audio" | "video" | "pdf" | "baml" => {}
 
                     cls if context.classes.contains_key(cls) => {}
+                    p if TypeValue::from_str(p).is_ok() => {}
 
                     _ => {
                         diagnostics.push_error(DatamodelError::new_validation_error(
@@ -2487,9 +2489,14 @@ pub fn typecheck_expression(
                     thir::Expr::Var(name, _) => {
                         if context.classes.get(name).is_some() {
                             Some(TypeIR::bool())
+                        } else if context.enums.get(name).is_some() {
+                            Some(TypeIR::bool())
+                        } else if TypeValue::from_str(name).is_ok() {
+                            Some(TypeIR::bool())
                         } else {
+                            // TODO: Check type aliases (may be recursive)
                             diagnostics.push_error(DatamodelError::new_validation_error(
-                                &format!("Class {name} not found"),
+                                &format!("Type {name} not found"),
                                 span.clone(),
                             ));
                             None
@@ -2497,7 +2504,7 @@ pub fn typecheck_expression(
                     }
                     _ => {
                         diagnostics.push_error(DatamodelError::new_validation_error(
-                            "Invalid binary operation (instanceof): right operand must be a class",
+                            "Invalid binary operation (instanceof): right operand must be a type",
                             span.clone(),
                         ));
                         None
diff --git a/integ-tests/baml_src/test-files/vm/expr_funcs.baml b/integ-tests/baml_src/test-files/vm/expr_funcs.baml
index edc592e422..946f77eec5 100644
--- a/integ-tests/baml_src/test-files/vm/expr_funcs.baml
+++ b/integ-tests/baml_src/test-files/vm/expr_funcs.baml
@@ -154,6 +154,12 @@ class DummyJsonTodo {
     userId int
 }
 
+enum DummyEnum {
+   POSITIVE
+   NEGATIVE
+   NEUTRAL
+}
+
 function ExecFetchAs(url: string) -> DummyJsonTodo {
     let todo = baml.fetch_as<DummyJsonTodo>(url);
 
@@ -165,3 +171,15 @@ test Fib5() {
   args { n 5 }
   @@assert( {{ this == 5 }} )
 }
+
+function InstanceofWithPrimitives(n: int) -> bool {
+    n instanceof int
+}
+
+function InstanceofWithClasses(dummy: DummyJsonTodo) -> bool {
+    dummy instanceof DummyJsonTodo
+}
+
+function InstanceofWithEnums(e: DummyEnum) -> bool {
+    e instanceof DummyEnum
+}