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Fix/instanceof operator on primitives #2618

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98a7262
feat(vscode): add debug configuration for baml-cli and build task
AntennaeVY Oct 15, 2025
eca2759
feat(typecheck): enhance instanceof type checking with support for pr…
AntennaeVY Oct 15, 2025
e2c8492
Merge branch 'canary' into fix/instanceof-operator-on-primitives
AntennaeVY Oct 17, 2025
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11 changes: 11 additions & 0 deletions .vscode/launch.json
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Original file line number Diff line number Diff line change
Expand Up @@ -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": "${workspaceFolder}/engine",
"env": { "RUST_LOG": "baml_cli=debug" },
"preLaunchTask": "build baml-cli",
"sourceLanguages": ["rust"]
}
],
"compounds": [
Expand Down
8 changes: 8 additions & 0 deletions .vscode/tasks.json
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Original file line number Diff line number Diff line change
Expand Up @@ -77,6 +77,14 @@
"endsPattern": "."
}
}
},
{
"label": "build baml-cli",
"type": "shell",
"command": "cargo",
"args": ["build", "--bin", "baml-cli"],
"options": { "cwd": "${workspaceFolder}/engine" },
"problemMatcher": ["$rustc"]
}
],
"inputs": [
Expand Down
13 changes: 10 additions & 3 deletions engine/baml-compiler/src/thir/typecheck.rs
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Expand Up @@ -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};

Expand Down Expand Up @@ -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() => {}
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correctness: TypeValue::from_str(p).is_ok() accepts any string that parses as a primitive or enum, but does not check if the type is actually defined in the current context, potentially allowing invalid types to pass silently.

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In engine/baml-compiler/src/thir/typecheck.rs, line 1360, the current check `TypeValue::from_str(p).is_ok()` allows any string that parses as a primitive or enum, even if the type is not defined in the current context. Update this line to only allow primitive types or enums that are actually defined in `context.enums` or are valid primitives. Replace the line with: `p if TypeValue::from_str(p).is_ok() && (context.enums.contains_key(p) || matches!(TypeValue::from_str(p), Ok(TypeValue::Primitive(_)))) => {}`.
📝 Committable Code Suggestion

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Suggested change
p if TypeValue::from_str(p).is_ok() => {}
p if TypeValue::from_str(p).is_ok() && (context.enums.contains_key(p) || matches!(TypeValue::from_str(p), Ok(TypeValue::Primitive(_)))) => {}


_ => {
diagnostics.push_error(DatamodelError::new_validation_error(
Expand Down Expand Up @@ -2487,17 +2489,22 @@ 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
}
}
_ => {
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
Expand Down
18 changes: 18 additions & 0 deletions integ-tests/baml_src/test-files/vm/expr_funcs.baml
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Original file line number Diff line number Diff line change
Expand Up @@ -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);

Expand All @@ -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
}