git.delta.rocks / jrsonnet / refs/commits / faca88a40d97

--- a/Cargo.lock
+++ b/Cargo.lock
@@ -310,6 +310,18 @@
 checksum = "9bda8e21c04aca2ae33ffc2fd8c23134f3cac46db123ba97bd9d3f3b8a4a85e1"
 
 [[package]]
+name = "educe"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d7bc049e1bd8cdeb31b68bbd586a9464ecf9f3944af3958a7a9d0f8b9799417"
+dependencies = [
+ "enum-ordinalize",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
 name = "either"
 version = "1.15.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -340,6 +352,26 @@
 ]
 
 [[package]]
+name = "enum-ordinalize"
+version = "4.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4a1091a7bb1f8f2c4b28f1fe2cef4980ca2d410a3d727d67ecc3178c9b0800f0"
+dependencies = [
+ "enum-ordinalize-derive",
+]
+
+[[package]]
+name = "enum-ordinalize-derive"
+version = "4.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8ca9601fb2d62598ee17836250842873a413586e5d7ed88b356e38ddbb0ec631"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
 name = "equivalent"
 version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -576,6 +608,7 @@
 dependencies = [
  "annotate-snippets",
  "anyhow",
+ "educe",
  "hi-doc",
  "jrsonnet-gcmodule",
  "jrsonnet-interner",

--- a/crates/jrsonnet-evaluator/Cargo.toml
+++ b/crates/jrsonnet-evaluator/Cargo.toml
@@ -57,6 +57,7 @@
 num-bigint = { workspace = true, features = ["serde"], optional = true }
 
 stacker = "0.1.23"
+educe = { version = "0.6.0", default-features = false, features = ["Clone", "Debug", "Eq", "Hash", "PartialEq"] }
 
 [build-dependencies]
 rustversion = "1.0.22"

--- a/crates/jrsonnet-evaluator/src/ctx.rs
+++ b/crates/jrsonnet-evaluator/src/ctx.rs
@@ -1,32 +1,27 @@
 use std::fmt::Debug;
 
+use educe::Educe;
 use jrsonnet_gcmodule::{Cc, Trace};
 use jrsonnet_interner::IStr;
 use rustc_hash::FxHashMap;
 
 use crate::{
 	error::ErrorKind::*, gc::WithCapacityExt as _, map::LayeredHashMap, ObjValue, Pending, Result,
-	Thunk, Val,
+	SupThis, Thunk, Val,
 };
+/// Context keeps information about current lexical code location
+///
+/// This information includes local variables, top-level object (`$`), current object (`this`), and super object (`super`)
+#[derive(Debug, Trace, Clone, Educe)]
+#[educe(PartialEq)]
+pub struct Context(#[educe(PartialEq(method = Cc::ptr_eq))] Cc<ContextInternal>);
 
-#[derive(Trace)]
-struct ContextInternals {
+#[derive(Debug, Trace)]
+struct ContextInternal {
 	dollar: Option<ObjValue>,
-	sup: Option<ObjValue>,
-	this: Option<ObjValue>,
+	sup_this: Option<SupThis>,
 	bindings: LayeredHashMap,
-}
-impl Debug for ContextInternals {
-	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-		f.debug_struct("Context").finish()
-	}
 }
-
-/// Context keeps information about current lexical code location
-///
-/// This information includes local variables, top-level object (`$`), current object (`this`), and super object (`super`)
-#[derive(Debug, Clone, Trace)]
-pub struct Context(Cc<ContextInternals>);
 impl Context {
 	pub fn new_future() -> Pending<Self> {
 		Pending::new()
@@ -36,12 +31,35 @@
 		self.0.dollar.as_ref()
 	}
 
+	pub fn try_dollar(&self) -> Result<ObjValue> {
+		self.0
+			.dollar
+			.clone()
+			.ok_or_else(|| CantUseSelfSupOutsideOfObject.into())
+	}
+
 	pub fn this(&self) -> Option<&ObjValue> {
-		self.0.this.as_ref()
+		self.0.sup_this.as_ref().map(SupThis::this)
+	}
+
+	pub fn try_this(&self) -> Result<ObjValue> {
+		self.0
+			.sup_this
+			.as_ref()
+			.ok_or_else(|| CantUseSelfSupOutsideOfObject.into())
+			.map(SupThis::this)
+			.cloned()
+	}
+
+	pub fn sup_this(&self) -> Option<&SupThis> {
+		self.0.sup_this.as_ref()
 	}
 
-	pub fn super_obj(&self) -> Option<&ObjValue> {
-		self.0.sup.as_ref()
+	pub fn try_sup_this(&self) -> Result<SupThis> {
+		self.0
+			.sup_this
+			.clone()
+			.ok_or_else(|| CantUseSelfSupOutsideOfObject.into())
 	}
 
 	pub fn binding(&self, name: IStr) -> Result<Thunk<Val>> {
@@ -83,41 +101,52 @@
 	pub fn with_var(self, name: impl Into<IStr>, value: Val) -> Self {
 		let mut new_bindings = FxHashMap::with_capacity(1);
 		new_bindings.insert(name.into(), Thunk::evaluated(value));
-		self.extend(new_bindings, None, None, None)
+		self.extend_bindings(new_bindings)
 	}
 
 	#[must_use]
-	pub fn extend(
+	pub fn extend_bindings_sup_this(
 		self,
 		new_bindings: FxHashMap<IStr, Thunk<Val>>,
-		new_dollar: Option<ObjValue>,
-		new_sup: Option<ObjValue>,
-		new_this: Option<ObjValue>,
+		sup_this: SupThis,
 	) -> Self {
-		let ctx = &self.0;
-		let dollar = new_dollar.or_else(|| ctx.dollar.clone());
-		let this = new_this.or_else(|| ctx.this.clone());
-		let sup = new_sup.or_else(|| ctx.sup.clone());
+		let ctx = &self;
+		let dollar = ctx
+			.0
+			.dollar
+			.clone()
+			.or_else(|| Some(sup_this.this().clone()));
 		let bindings = if new_bindings.is_empty() {
-			ctx.bindings.clone()
+			ctx.0.bindings.clone()
 		} else {
-			ctx.bindings.clone().extend(new_bindings)
+			ctx.0.bindings.clone().extend(new_bindings)
 		};
-		Self(Cc::new(ContextInternals {
+		Self(Cc::new(ContextInternal {
 			dollar,
-			sup,
-			this,
+			sup_this: Some(sup_this),
 			bindings,
 		}))
 	}
-}
-
-impl PartialEq for Context {
-	fn eq(&self, other: &Self) -> bool {
-		Cc::ptr_eq(&self.0, &other.0)
+	#[must_use]
+	pub fn extend_bindings(self, new_bindings: FxHashMap<IStr, Thunk<Val>>) -> Self {
+		if new_bindings.is_empty() {
+			return self;
+		}
+		let ctx = &self;
+		let bindings = if new_bindings.is_empty() {
+			ctx.0.bindings.clone()
+		} else {
+			ctx.0.bindings.clone().extend(new_bindings)
+		};
+		Self(Cc::new(ContextInternal {
+			dollar: ctx.0.dollar.clone(),
+			sup_this: ctx.0.sup_this.clone(),
+			bindings,
+		}))
 	}
 }
 
+#[derive(Default)]
 pub struct ContextBuilder {
 	bindings: FxHashMap<IStr, Thunk<Val>>,
 	extend: Option<Context>,
@@ -127,20 +156,25 @@
 	pub fn new() -> Self {
 		Self::with_capacity(0)
 	}
+
 	pub fn with_capacity(capacity: usize) -> Self {
 		Self {
 			bindings: FxHashMap::with_capacity(capacity),
 			extend: None,
 		}
 	}
+
 	pub fn extend(parent: Context) -> Self {
 		Self {
 			bindings: FxHashMap::new(),
 			extend: Some(parent),
 		}
 	}
+
 	/// # Panics
-	/// If `name` is already bound
+	///
+	/// If `name` is already bound. Makes no sense to bind same local multiple times,
+	/// unless it is separate context layers.
 	pub fn bind(&mut self, name: impl Into<IStr>, value: Thunk<Val>) -> &mut Self {
 		let old = self.bindings.insert(name.into(), value);
 		assert!(old.is_none(), "variable bound twice in single context call");
@@ -148,14 +182,12 @@
 	}
 	pub fn build(self) -> Context {
 		if let Some(parent) = self.extend {
-			// TODO: replace self.extend with Result<Context, State>, and remove `state` field
-			parent.extend(self.bindings, None, None, None)
+			parent.extend_bindings(self.bindings)
 		} else {
-			Context(Cc::new(ContextInternals {
+			Context(Cc::new(ContextInternal {
 				bindings: LayeredHashMap::new(self.bindings),
 				dollar: None,
-				sup: None,
-				this: None,
+				sup_this: None,
 			}))
 		}
 	}

--- a/crates/jrsonnet-evaluator/src/dynamic.rs
+++ b/crates/jrsonnet-evaluator/src/dynamic.rs
@@ -1,11 +1,13 @@
-use std::cell::OnceCell;
+use std::ptr::addr_of;
+use std::{cell::OnceCell, hash::Hasher};
 
+use educe::Educe;
 use jrsonnet_gcmodule::{Cc, Trace};
 
 use crate::{bail, error::ErrorKind::InfiniteRecursionDetected, val::ThunkValue, Result};
 
-// TODO: Replace with OnceCell once in std
-#[derive(Clone, Trace)]
+#[derive(Trace, Educe)]
+#[educe(Clone)]
 pub struct Pending<V: Trace + 'static>(pub Cc<OnceCell<V>>);
 impl<T: Trace + 'static> Pending<T> {
 	pub fn new() -> Self {
@@ -25,7 +27,7 @@
 			.expect("wrapper is filled already");
 	}
 }
-impl<T: Clone + Trace + 'static> Pending<T> {
+impl<T: Trace + 'static + Clone> Pending<T> {
 	/// # Panics
 	/// If wrapper is not yet filled
 	pub fn unwrap(&self) -> T {
@@ -52,3 +54,7 @@
 		Self::new()
 	}
 }
+
+pub fn identity_hash<T, H: Hasher>(v: &Cc<T>, hasher: &mut H) {
+	hasher.write_usize(addr_of!(**v) as usize);
+}

--- a/crates/jrsonnet-evaluator/src/error.rs
+++ b/crates/jrsonnet-evaluator/src/error.rs
@@ -119,10 +119,8 @@
 	#[error("binary operation {1} {0} {2} is not implemented")]
 	BinaryOperatorDoesNotOperateOnValues(BinaryOpType, ValType, ValType),
 
-	#[error("no top level object in this context")]
-	NoTopLevelObjectFound,
-	#[error("self is only usable inside objects")]
-	CantUseSelfOutsideOfObject,
+	#[error("self/super/$ are only usable inside objects")]
+	CantUseSelfSupOutsideOfObject,
 	#[error("no super found")]
 	NoSuperFound,
 

--- a/crates/jrsonnet-evaluator/src/evaluate/mod.rs
+++ b/crates/jrsonnet-evaluator/src/evaluate/mod.rs
@@ -11,18 +11,7 @@
 
 use self::destructure::destruct;
 use crate::{
-	arr::ArrValue,
-	bail,
-	destructure::evaluate_dest,
-	error::{suggest_object_fields, ErrorKind::*},
-	evaluate::operator::{evaluate_add_op, evaluate_binary_op_special, evaluate_unary_op},
-	function::{CallLocation, FuncDesc, FuncVal},
-	gc::WithCapacityExt as _,
-	in_frame,
-	typed::Typed,
-	val::{CachedUnbound, IndexableVal, NumValue, StrValue, Thunk},
-	Context, Error, ObjValue, ObjValueBuilder, ObjectAssertion, Pending, Result, ResultExt,
-	Unbound, Val,
+	Context, Error, ObjValue, ObjValueBuilder, ObjectAssertion, Pending, Result, ResultExt, SupThis, Unbound, Val, arr::ArrValue, bail, destructure::evaluate_dest, error::{ErrorKind::*, suggest_object_fields}, evaluate::operator::{evaluate_add_op, evaluate_binary_op_special, evaluate_unary_op}, function::{CallLocation, FuncDesc, FuncVal}, gc::WithCapacityExt as _, in_frame, typed::Typed, val::{CachedUnbound, IndexableVal, NumValue, StrValue, Thunk}, with_state
 };
 pub mod destructure;
 pub mod operator;
@@ -126,10 +115,7 @@
 					let fctx = Pending::new();
 					let mut new_bindings = FxHashMap::with_capacity(var.capacity_hint());
 					destruct(var, item, fctx.clone(), &mut new_bindings)?;
-					let ctx = ctx
-						.clone()
-						.extend(new_bindings, None, None, None)
-						.into_future(fctx);
+					let ctx = ctx.clone().extend_bindings(new_bindings).into_future(fctx);
 
 					evaluate_comp(ctx, &specs[1..], callback)?;
 				}
@@ -169,18 +155,18 @@
 impl<V, T> CloneableUnbound<T> for V where V: Unbound<Bound = T> + Clone {}
 
 fn evaluate_object_locals(
-	fctx: Pending<Context>,
+	fctx: Context,
 	locals: Rc<Vec<BindSpec>>,
 ) -> impl CloneableUnbound<Context> {
 	#[derive(Trace, Clone)]
 	struct UnboundLocals {
-		fctx: Pending<Context>,
+		fctx: Context,
 		locals: Rc<Vec<BindSpec>>,
 	}
 	impl Unbound for UnboundLocals {
 		type Bound = Context;
 
-		fn bind(&self, sup: Option<ObjValue>, this: Option<ObjValue>) -> Result<Context> {
+		fn bind(&self, sup_this: SupThis) -> Result<Context> {
 			let fctx = Context::new_future();
 			let mut new_bindings =
 				FxHashMap::with_capacity(self.locals.iter().map(BindSpec::capacity_hint).sum());
@@ -188,11 +174,10 @@
 				evaluate_dest(b, fctx.clone(), &mut new_bindings)?;
 			}
 
-			let ctx = self.fctx.unwrap();
-			let new_dollar = ctx.dollar().cloned().or_else(|| this.clone());
+			let ctx = self.fctx.clone();
 
 			let ctx = ctx
-				.extend(new_bindings, new_dollar, sup, this)
+				.extend_bindings_sup_this(new_bindings, sup_this)
 				.into_future(fctx);
 
 			Ok(ctx)
@@ -229,8 +214,8 @@
 			}
 			impl<B: Unbound<Bound = Context>> Unbound for UnboundValue<B> {
 				type Bound = Val;
-				fn bind(&self, sup: Option<ObjValue>, this: Option<ObjValue>) -> Result<Val> {
-					evaluate_named(self.uctx.bind(sup, this)?, &self.value, self.name.clone())
+				fn bind(&self, sup_this: SupThis) -> Result<Val> {
+					evaluate_named(self.uctx.bind(sup_this)?, &self.value, self.name.clone())
 				}
 			}
 
@@ -260,9 +245,9 @@
 			}
 			impl<B: Unbound<Bound = Context>> Unbound for UnboundMethod<B> {
 				type Bound = Val;
-				fn bind(&self, sup: Option<ObjValue>, this: Option<ObjValue>) -> Result<Val> {
+				fn bind(&self, sup_this: SupThis) -> Result<Val> {
 					Ok(evaluate_method(
-						self.uctx.bind(sup, this)?,
+						self.uctx.bind(sup_this)?,
 						self.name.clone(),
 						self.params.clone(),
 						self.value.clone(),
@@ -298,10 +283,8 @@
 			.collect::<Vec<_>>(),
 	);
 
-	let fctx = Context::new_future();
-
 	// We have single context for all fields, so we can cache binds
-	let uctx = CachedUnbound::new(evaluate_object_locals(fctx.clone(), locals));
+	let uctx = CachedUnbound::new(evaluate_object_locals(ctx.clone(), locals));
 
 	for member in members {
 		match member {
@@ -315,8 +298,8 @@
 					assert: AssertStmt,
 				}
 				impl<B: Unbound<Bound = Context>> ObjectAssertion for ObjectAssert<B> {
-					fn run(&self, sup: Option<ObjValue>, this: Option<ObjValue>) -> Result<()> {
-						let ctx = self.uctx.bind(sup, this)?;
+					fn run(&self, sup_this: SupThis) -> Result<()> {
+						let ctx = self.uctx.bind(sup_this)?;
 						evaluate_assert(ctx, &self.assert)
 					}
 				}
@@ -330,9 +313,7 @@
 			}
 		}
 	}
-	let this = builder.build();
-	fctx.fill(ctx.extend(FxHashMap::new(), None, None, Some(this.clone())));
-	Ok(this)
+	Ok(builder.build())
 }
 
 pub fn evaluate_object(ctx: Context, object: &ObjBody) -> Result<ObjValue> {
@@ -347,22 +328,13 @@
 					.cloned()
 					.collect::<Vec<_>>(),
 			);
-			let mut ctxs = vec![];
 			evaluate_comp(ctx, &obj.compspecs, &mut |ctx| {
-				let fctx = Context::new_future();
-				ctxs.push((ctx.clone(), fctx.clone()));
-				let uctx = evaluate_object_locals(fctx, locals.clone());
+				let uctx = evaluate_object_locals(ctx.clone(), locals.clone());
 
 				evaluate_field_member(&mut builder, ctx, uctx, &obj.field)
 			})?;
 
-			let this = builder.build();
-			for (ctx, fctx) in ctxs {
-				let _ctx = ctx
-					.extend(FxHashMap::new(), None, None, Some(this.clone()))
-					.into_future(fctx);
-			}
-			this
+			builder.build()
 		}
 	})
 }
@@ -428,19 +400,9 @@
 	}
 	let loc = expr.span();
 	Ok(match expr.expr() {
-		Literal(LiteralType::This) => {
-			Val::Obj(ctx.this().ok_or(CantUseSelfOutsideOfObject)?.clone())
-		}
-		Literal(LiteralType::Super) => Val::Obj(
-			ctx.super_obj().ok_or(NoSuperFound)?.with_this(
-				ctx.this()
-					.expect("if super exists - then this should too")
-					.clone(),
-			),
-		),
-		Literal(LiteralType::Dollar) => {
-			Val::Obj(ctx.dollar().ok_or(NoTopLevelObjectFound)?.clone())
-		}
+		Literal(LiteralType::This) => Val::Obj(ctx.try_this()?),
+		Literal(LiteralType::Super) => Val::Obj(ctx.try_sup_this()?.standalone_super()?),
+		Literal(LiteralType::Dollar) => Val::Obj(ctx.try_dollar()?),
 		Literal(LiteralType::True) => Val::Bool(true),
 		Literal(LiteralType::False) => Val::Bool(false),
 		Literal(LiteralType::Null) => Val::Null,
@@ -452,15 +414,18 @@
 		//
 		// Note that other jsonnet implementations will fail on `if value in (super)` expression,
 		// because the standalone super literal is not supported, that is because in other
-		// implementations `in super` treated differently from in `smth_else`.
+		// implementations `in super` treated differently from `in smth_else`.
 		BinaryOp(field, BinaryOpType::In, e)
 			if matches!(e.expr(), Expr::Literal(LiteralType::Super)) =>
 		{
-			let Some(super_obj) = ctx.super_obj() else {
+			let sup_this = ctx.try_sup_this()?;
+			// In jsonnet, "field" in e is eager, LHS expression is always executed regardless of super existence.
+			// In jrsonnet, however, this wasn't true, this was kept here for compatibility.
+			if !sup_this.has_super() {
 				return Ok(Val::Bool(false));
-			};
-			let field = evaluate(ctx.clone(), field)?;
-			Val::Bool(super_obj.has_field_ex(field.to_string()?, true))
+			}
+			let field = evaluate(ctx, field)?;
+			Val::Bool(sup_this.field_in_super(field.to_string()?))
 		}
 		BinaryOp(v1, o, v2) => evaluate_binary_op_special(ctx, v1, *o, v2)?,
 		UnaryOp(o, v) => evaluate_unary_op(*o, &evaluate(ctx, v)?)?,
@@ -473,13 +438,16 @@
 			let mut parts = parts.iter();
 			let mut indexable = if matches!(indexable.expr(), Expr::Literal(LiteralType::Super)) {
 				let part = parts.next().expect("at least part should exist");
-				let Some(super_obj) = ctx.super_obj() else {
+				// sup_this existence check might also be skipped here for null-coalesce...
+				// But I believe this might cause errors.
+				let sup_this = ctx.try_sup_this()?;
+				if !sup_this.has_super() {
 					#[cfg(feature = "exp-null-coaelse")]
 					if part.null_coaelse {
 						return Ok(Val::Null);
 					}
 					bail!(NoSuperFound)
-				};
+				}
 				let name = evaluate(ctx.clone(), &part.value)?;
 
 				let Val::Str(name) = name else {
@@ -490,19 +458,19 @@
 					))
 				};
 
-				let this = ctx
-					.this()
-					.expect("no this found, while super present, should not happen");
 				let name = name.into_flat();
-				match super_obj
-					.get_for(name.clone(), this.clone())
+				match sup_this
+					.get_super(name.clone())
 					.with_description_src(&part.value, || format!("field <{name}> access"))?
 				{
 					Some(v) => v,
 					#[cfg(feature = "exp-null-coaelse")]
 					None if part.null_coaelse => return Ok(Val::Null),
 					None => {
-						let suggestions = suggest_object_fields(super_obj, name.clone());
+						let suggestions = suggest_object_fields(
+							&sup_this.standalone_super().expect("super exists"),
+							name.clone(),
+						);
 
 						bail!(NoSuchField(name, suggestions))
 					}
@@ -589,7 +557,7 @@
 			for b in bindings {
 				evaluate_dest(b, fctx.clone(), &mut new_bindings)?;
 			}
-			let ctx = ctx.extend(new_bindings, None, None, None).into_future(fctx);
+			let ctx = ctx.extend_bindings(new_bindings).into_future(fctx);
 			evaluate(ctx, &returned.clone())?
 		}
 		Arr(items) => {
@@ -652,7 +620,7 @@
 		Slice(value, desc) => {
 			fn parse_idx<T: Typed>(
 				loc: CallLocation<'_>,
-				ctx: &Context,
+				ctx: Context,
 				expr: Option<&LocExpr>,
 				desc: &'static str,
 			) -> Result<Option<T>> {
@@ -660,7 +628,7 @@
 					Ok(in_frame(
 						loc,
 						|| format!("slice {desc}"),
-						|| <Option<T>>::from_untyped(evaluate(ctx.clone(), value)?),
+						|| <Option<T>>::from_untyped(evaluate(ctx, value)?),
 					)?)
 				} else {
 					Ok(None)
@@ -670,9 +638,9 @@
 			let indexable = evaluate(ctx.clone(), value)?;
 			let loc = CallLocation::new(&loc);
 
-			let start = parse_idx(loc, &ctx, desc.start.as_ref(), "start")?;
-			let end = parse_idx(loc, &ctx, desc.end.as_ref(), "end")?;
-			let step = parse_idx(loc, &ctx, desc.step.as_ref(), "step")?;
+			let start = parse_idx(loc, ctx.clone(), desc.start.as_ref(), "start")?;
+			let end = parse_idx(loc, ctx.clone(), desc.end.as_ref(), "end")?;
+			let step = parse_idx(loc, ctx, desc.step.as_ref(), "step")?;
 
 			IndexableVal::into_untyped(indexable.into_indexable()?.slice(start, end, step)?)?
 		}
@@ -681,18 +649,21 @@
 				bail!("computed imports are not supported")
 			};
 			let tmp = loc.clone().0;
-			let s = ctx.state();
-			let resolved_path = s.resolve_from(tmp.source_path(), path)?;
-			match i {
-				Import(_) => in_frame(
-					CallLocation::new(&loc),
-					|| format!("import {:?}", path.clone()),
-					|| s.import_resolved(resolved_path),
-				)?,
-				ImportStr(_) => Val::string(s.import_resolved_str(resolved_path)?),
-				ImportBin(_) => Val::Arr(ArrValue::bytes(s.import_resolved_bin(resolved_path)?)),
-				_ => unreachable!(),
-			}
+			with_state(|s| {
+				let resolved_path = s.resolve_from(tmp.source_path(), path)?;
+				Ok(match i {
+					Import(_) => in_frame(
+						CallLocation::new(&loc),
+						|| format!("import {:?}", path.clone()),
+						|| s.import_resolved(resolved_path),
+					)?,
+					ImportStr(_) => Val::string(s.import_resolved_str(resolved_path)?),
+					ImportBin(_) => {
+						Val::Arr(ArrValue::bytes(s.import_resolved_bin(resolved_path)?))
+					}
+					_ => unreachable!(),
+				}) as Result<Val>
+			})?
 		}
 	})
 }

--- a/crates/jrsonnet-evaluator/src/function/mod.rs
+++ b/crates/jrsonnet-evaluator/src/function/mod.rs
@@ -40,7 +40,7 @@
 }
 
 /// Represents Jsonnet function defined in code.
-#[derive(Debug, PartialEq, Trace)]
+#[derive(Debug, Trace, PartialEq)]
 pub struct FuncDesc {
 	/// # Example
 	///

--- a/crates/jrsonnet-evaluator/src/function/parse.rs
+++ b/crates/jrsonnet-evaluator/src/function/parse.rs
@@ -129,11 +129,11 @@
 		}
 
 		Ok(body_ctx
-			.extend(passed_args, None, None, None)
-			.extend(defaults, None, None, None)
+			.extend_bindings(passed_args)
+			.extend_bindings(defaults)
 			.into_future(fctx))
 	} else {
-		let body_ctx = body_ctx.extend(passed_args, None, None, None);
+		let body_ctx = body_ctx.extend_bindings(passed_args);
 		Ok(body_ctx)
 	}
 }
@@ -257,7 +257,5 @@
 		}
 	}
 
-	Ok(body_ctx
-		.extend(bindings, None, None, None)
-		.into_future(fctx))
+	Ok(body_ctx.extend_bindings(bindings).into_future(fctx))
 }

--- a/crates/jrsonnet-evaluator/src/lib.rs
+++ b/crates/jrsonnet-evaluator/src/lib.rs
@@ -28,8 +28,10 @@
 	any::Any,
 	cell::{RefCell, RefMut},
 	collections::hash_map::Entry,
+	clone::Clone,
 	fmt::{self, Debug},
 	rc::Rc,
+	marker::PhantomData,
 };
 
 pub use ctx::*;
@@ -65,7 +67,7 @@
 	/// Type of value after object context is bound
 	type Bound;
 	/// Create value bound to specified object context
-	fn bind(&self, sup: Option<ObjValue>, this: Option<ObjValue>) -> Result<Self::Bound>;
+	fn bind(&self, sup_this: SupThis) -> Result<Self::Bound>;
 }
 
 /// Object fields may, or may not depend on `this`/`super`, this enum allows cheaper reuse of object-independent fields for native code
@@ -85,9 +87,9 @@
 }
 impl MaybeUnbound {
 	/// Attach object context to value, if required
-	pub fn evaluate(&self, sup: Option<ObjValue>, this: Option<ObjValue>) -> Result<Val> {
+	pub fn evaluate(&self, sup_this: SupThis) -> Result<Val> {
 		match self {
-			Self::Unbound(v) => v.0.bind(sup, this),
+			Self::Unbound(v) => v.0.bind(sup_this),
 			Self::Bound(v) => Ok(v.evaluate()?),
 		}
 	}
@@ -105,8 +107,8 @@
 	/// Initialize default file context.
 	/// Has default implementation, which calls `populate`.
 	/// Prefer to always implement `populate` instead.
-	fn initialize(&self, state: State, for_file: Source) -> Context {
-		let mut builder = ContextBuilder::with_capacity(state, self.reserve_vars());
+	fn initialize(&self, for_file: Source) -> Context {
+		let mut builder = ContextBuilder::with_capacity(self.reserve_vars());
 		self.populate(for_file, &mut builder);
 		builder.build()
 	}
@@ -130,11 +132,11 @@
 where
 	T: ContextInitializer,
 {
-	fn initialize(&self, state: State, for_file: Source) -> Context {
+	fn initialize(&self, for_file: Source) -> Context {
 		if let Some(ctx) = self {
-			ctx.initialize(state, for_file)
+			ctx.initialize(for_file)
 		} else {
-			().initialize(state, for_file)
+			().initialize(for_file)
 		}
 	}
 
@@ -237,7 +239,40 @@
 #[derive(Clone, Trace)]
 pub struct State(Cc<EvaluationStateInternals>);
 
+thread_local! {
+	pub static DEFAULT_STATE: State = State::builder().build();
+	pub static STATE: RefCell<Option<State>> = const {RefCell::new(None)};
+}
+pub struct StateEnterGuard(PhantomData<()>);
+impl Drop for StateEnterGuard {
+	fn drop(&mut self) {
+		STATE.with_borrow_mut(|v| *v = None);
+	}
+}
+
+pub fn with_state<V>(v: impl FnOnce(State) -> V) -> V {
+	if let Some(state) = STATE.with_borrow(Clone::clone) {
+		v(state)
+	} else {
+		let s = DEFAULT_STATE.with(Clone::clone);
+		v(s)
+	}
+}
+
 impl State {
+	pub fn enter(&self) -> StateEnterGuard {
+		self.try_enter().expect("entered state already exists")
+	}
+	pub fn try_enter(&self) -> Option<StateEnterGuard> {
+		STATE.with_borrow_mut(|v| {
+			if v.is_none() {
+				*v = Some(self.clone());
+				Some(StateEnterGuard(PhantomData))
+			} else {
+				None
+			}
+		})
+	}
 	/// Should only be called with path retrieved from [`resolve_path`], may panic otherwise
 	pub fn import_resolved_str(&self, path: SourcePath) -> Result<IStr> {
 		let mut file_cache = self.file_cache();
@@ -359,7 +394,7 @@
 
 	/// Creates context with all passed global variables
 	pub fn create_default_context(&self, source: Source) -> Context {
-		self.context_initializer().initialize(self.clone(), source)
+		self.context_initializer().initialize(source)
 	}
 
 	/// Creates context with all passed global variables, calling custom modifier
@@ -370,7 +405,6 @@
 	) -> Context {
 		let default_initializer = self.context_initializer();
 		let mut builder = ContextBuilder::with_capacity(
-			self.clone(),
 			default_initializer.reserve_vars() + context_initializer.reserve_vars(),
 		);
 		default_initializer.populate(source.clone(), &mut builder);

--- a/crates/jrsonnet-evaluator/src/map.rs
+++ b/crates/jrsonnet-evaluator/src/map.rs
@@ -4,14 +4,14 @@
 
 use crate::{gc::WithCapacityExt as _, Thunk, Val};
 
-#[derive(Trace)]
+#[derive(Trace, Debug)]
 #[trace(tracking(force))]
 pub struct LayeredHashMapInternals {
 	parent: Option<LayeredHashMap>,
 	current: FxHashMap<IStr, Thunk<Val>>,
 }
 
-#[derive(Trace)]
+#[derive(Trace, Debug)]
 pub struct LayeredHashMap(Cc<LayeredHashMapInternals>);
 
 impl LayeredHashMap {

--- a/crates/jrsonnet-evaluator/src/obj.rs
+++ b/crates/jrsonnet-evaluator/src/obj.rs
@@ -1,12 +1,9 @@
 use std::{
-	any::Any,
-	cell::RefCell,
-	fmt::Debug,
-	hash::{Hash, Hasher},
-	ptr::addr_of,
+	any::Any, cell::{Cell, RefCell}, collections::hash_map::Entry, fmt::{self, Debug}, hash::{Hash, Hasher}
 };
 
 use jrsonnet_gcmodule::{cc_dyn, Cc, Trace, Weak};
+use educe::Educe;
 use jrsonnet_interner::IStr;
 use jrsonnet_parser::{Span, Visibility};
 use rustc_hash::{FxHashMap, FxHashSet};
@@ -14,10 +11,11 @@
 use crate::{
 	arr::{PickObjectKeyValues, PickObjectValues},
 	bail,
-	error::{suggest_object_fields, Error, ErrorKind::*},
+	error::{suggest_object_fields, ErrorKind::*},
 	function::{CallLocation, FuncVal},
 	gc::WithCapacityExt as _,
 	in_frame,
+	identity_hash, 
 	operator::evaluate_add_op,
 	val::ArrValue,
 	CcUnbound, MaybeUnbound, Result, Thunk, Unbound, Val,
@@ -43,12 +41,10 @@
 	#[derive(Clone, Copy, Default, Debug, Trace)]
 	pub struct SuperDepth(());
 	impl SuperDepth {
-		pub const fn deeper(self) -> Self {
-			Self(())
-		}
+		pub(super) fn deepen(self) {}
 	}
 
-	#[derive(Clone, Copy)]
+	#[derive(Clone, Copy, Debug)]
 	pub struct FieldSortKey(());
 	impl FieldSortKey {
 		pub const fn new(_: SuperDepth, _: FieldIndex) -> Self {
@@ -74,8 +70,8 @@
 	#[derive(Clone, Copy, Default, PartialEq, Eq, PartialOrd, Ord, Debug)]
 	pub struct SuperDepth(u32);
 	impl SuperDepth {
-		pub fn deeper(self) -> Self {
-			Self(self.0 + 1)
+		pub(super) fn deepen(&mut self) {
+			*self.0 += 1
 		}
 	}
 
@@ -120,7 +116,7 @@
 	}
 }
 impl Debug for ObjFieldFlags {
-	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 		f.debug_struct("ObjFieldFlags")
 			.field("add", &self.add())
 			.field("visibility", &self.visibility())
@@ -140,34 +136,29 @@
 
 cc_dyn!(CcObjectAssertion, ObjectAssertion);
 pub trait ObjectAssertion: Trace {
-	fn run(&self, super_obj: Option<ObjValue>, this: Option<ObjValue>) -> Result<()>;
+	fn run(&self, sup_this: SupThis) -> Result<()>;
 }
 
 // Field => This
 
-#[derive(Trace)]
+#[derive(Trace, Debug)]
 enum CacheValue {
-	Cached(Val),
-	NotFound,
+	Cached(Result<Option<Val>>),
 	Pending,
-	Errored(Error),
 }
 
 #[allow(clippy::module_name_repetitions)]
 #[derive(Trace)]
 #[trace(tracking(force))]
 pub struct OopObject {
-	sup: Option<ObjValue>,
 	// this: Option<ObjValue>,
 	assertions: Cc<Vec<CcObjectAssertion>>,
-	assertions_ran: RefCell<FxHashSet<ObjValue>>,
 	this_entries: Cc<FxHashMap<IStr, ObjMember>>,
 	value_cache: RefCell<FxHashMap<(IStr, Option<WeakObjValue>), CacheValue>>,
 }
 impl Debug for OopObject {
 	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 		f.debug_struct("OopObject")
-			.field("sup", &self.sup)
 			// .field("assertions", &self.assertions)
 			// .field("assertions_ran", &self.assertions_ran)
 			.field("this_entries", &self.this_entries)
@@ -178,32 +169,36 @@
 
 type EnumFieldsHandler<'a> = dyn FnMut(SuperDepth, FieldIndex, IStr, Visibility) -> bool + 'a;
 
-pub trait ObjectLike: Trace + Any + Debug {
-	fn extend_from(&self, sup: ObjValue) -> ObjValue;
-	/// When using standalone super in object, `this.super_obj.with_this(this)` is executed
-	fn with_this(&self, me: ObjValue, this: ObjValue) -> ObjValue {
-		ObjValue::new(ThisOverride { inner: me, this })
-	}
-	fn this(&self) -> Option<ObjValue> {
-		None
-	}
-	fn len(&self) -> usize;
-	fn is_empty(&self) -> bool;
-	// If callback returns false, iteration stops
-	fn enum_fields(&self, depth: SuperDepth, handler: &mut EnumFieldsHandler<'_>) -> bool;
+#[derive(Trace, Clone)]
+pub enum ValueProcess {
+	None,
+	SuperPlus,
+}
+
+pub trait ObjectCore: Trace + Any + Debug {
+	// If callback returns false, iteration stops, and this call returns false.
+	fn enum_fields_core(
+		&self,
+		super_depth: &mut SuperDepth,
+		handler: &mut EnumFieldsHandler<'_>,
+	) -> bool;
 
 	fn has_field_include_hidden(&self, name: IStr) -> bool;
-	fn has_field(&self, name: IStr) -> bool;
 
-	fn get_for(&self, key: IStr, this: ObjValue) -> Result<Option<Val>>;
-	fn get_for_uncached(&self, key: IStr, this: ObjValue) -> Result<Option<Val>>;
+	fn get_for(&self, key: IStr, sup_this: SupThis) -> Result<Option<(Val, ValueProcess)>>;
+	// fn get_for_uncached(&self, key: IStr, this: ObjValue) -> Result<Option<(Val, ValueProcess)>>;
 	fn field_visibility(&self, field: IStr) -> Option<Visibility>;
 
-	fn run_assertions_raw(&self, this: ObjValue) -> Result<()>;
+	fn run_assertions_raw(&self, sup_this: SupThis) -> Result<()>;
 }
 
 #[derive(Clone, Trace)]
-pub struct WeakObjValue(#[trace(skip)] pub(crate) Weak<dyn ObjectLike>);
+pub struct WeakObjValue(#[trace(skip)] Weak<ObjValueInner>);
+impl Debug for WeakObjValue {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		f.debug_tuple("WeakObjValue").finish()
+	}
+}
 
 impl PartialEq for WeakObjValue {
 	fn eq(&self, other: &Self) -> bool {
@@ -222,50 +217,97 @@
 
 cc_dyn!(
 	#[derive(Clone, Debug)]
-	ObjValue, ObjectLike,
+	ObjCore, ObjectCore,
 	pub fn new() {...}
 );
+#[derive(Trace, Educe)]
+#[educe(Debug)]
+struct ObjValueInner {
+	cores: Vec<ObjCore>,
+	assertions_ran: Cell<bool>,
+	value_cache: RefCell<FxHashMap<(IStr, CoreIdx), CacheValue>>,
+}
 
-#[derive(Debug, Trace)]
-struct EmptyObject;
-impl ObjectLike for EmptyObject {
-	fn extend_from(&self, sup: ObjValue) -> ObjValue {
-		// obj + {} == obj
-		sup
+thread_local! {
+	static RUNNING_ASSERTIONS: RefCell<FxHashSet<ObjValue>> = RefCell::default();
+}
+fn is_asserting(obj: &ObjValue) -> bool {
+	RUNNING_ASSERTIONS.with_borrow(|v| v.contains(obj))
+}
+/// Returns false if already asserting
+fn start_asserting(obj: &ObjValue) -> bool {
+	RUNNING_ASSERTIONS.with_borrow_mut(|v| v.insert(obj.clone()))
+}
+fn finish_asserting(obj: &ObjValue) {
+	RUNNING_ASSERTIONS.with_borrow_mut(|v| {
+		let r = v.remove(obj);
+		debug_assert!(
+			r,
+			"finish_asserting was called before start_asserting or twice"
+		);
+	});
+}
+
+#[allow(clippy::module_name_repetitions)]
+#[derive(Clone, Trace, Debug, Educe)]
+#[educe(PartialEq, Hash, Eq)]
+pub struct ObjValue(
+	#[educe(PartialEq(method(Cc::ptr_eq)), Hash(method(identity_hash)))] Cc<ObjValueInner>,
+);
+
+#[derive(Trace, Debug)]
+struct StandaloneSuperCore {
+	sup: CoreIdx,
+	this: ObjValue,
+}
+impl ObjectCore for StandaloneSuperCore {
+	fn enum_fields_core(
+		&self,
+		super_depth: &mut SuperDepth,
+		handler: &mut EnumFieldsHandler<'_>,
+	) -> bool {
+		self.this
+			.enum_fields_internal(super_depth, handler, self.sup)
 	}
 
-	fn this(&self) -> Option<ObjValue> {
-		None
+	fn has_field_include_hidden(&self, name: IStr) -> bool {
+		self.this.has_field_include_hidden_idx(name, self.sup)
 	}
 
-	fn len(&self) -> usize {
-		0
+	fn get_for(&self, key: IStr, _sup_this: SupThis) -> Result<Option<(Val, ValueProcess)>> {
+		let v = self.this.get_idx(key, self.sup)?;
+		Ok(v.map(|v| (v, ValueProcess::None)))
 	}
 
-	fn is_empty(&self) -> bool {
-		true
+	fn field_visibility(&self, field: IStr) -> Option<Visibility> {
+		self.this.field_visibility_idx(field, self.sup)
 	}
 
-	fn enum_fields(&self, _depth: SuperDepth, _handler: &mut EnumFieldsHandler<'_>) -> bool {
-		false
+	fn run_assertions_raw(&self, _sup_this: SupThis) -> Result<()> {
+		self.this.run_assertions()
 	}
+}
 
-	fn has_field_include_hidden(&self, _name: IStr) -> bool {
-		false
+#[derive(Debug, Trace)]
+struct EmptyObject;
+impl ObjectCore for EmptyObject {
+	fn enum_fields_core(
+		&self,
+		_super_depth: &mut SuperDepth,
+		_handler: &mut EnumFieldsHandler<'_>,
+	) -> bool {
+		true
 	}
 
-	fn has_field(&self, _name: IStr) -> bool {
+	fn has_field_include_hidden(&self, _name: IStr) -> bool {
 		false
 	}
 
-	fn get_for(&self, _key: IStr, _this: ObjValue) -> Result<Option<Val>> {
-		Ok(None)
-	}
-	fn get_for_uncached(&self, _key: IStr, _this: ObjValue) -> Result<Option<Val>> {
+	fn get_for(&self, _key: IStr, _sup_this: SupThis) -> Result<Option<(Val, ValueProcess)>> {
 		Ok(None)
 	}
 
-	fn run_assertions_raw(&self, _this: ObjValue) -> Result<()> {
+	fn run_assertions_raw(&self, _sup_this: SupThis) -> Result<()> {
 		Ok(())
 	}
 
@@ -274,65 +316,79 @@
 	}
 }
 
-#[derive(Trace, Debug)]
-struct ThisOverride {
-	inner: ObjValue,
-	this: ObjValue,
+#[derive(Hash, PartialEq, Eq, Trace, Clone, Copy, Debug)]
+struct CoreIdx {
+	idx: usize,
 }
-impl ObjectLike for ThisOverride {
-	fn with_this(&self, _me: ObjValue, this: ObjValue) -> ObjValue {
-		ObjValue::new(Self {
-			inner: self.inner.clone(),
-			this,
-		})
+impl CoreIdx {
+	fn super_exists(self) -> bool {
+		self.idx != 0
 	}
-
-	fn extend_from(&self, sup: ObjValue) -> ObjValue {
-		self.inner.extend_from(sup).with_this(self.this.clone())
+}
+#[derive(Trace, Clone, PartialEq, Eq, Hash, Debug)]
+pub struct SupThis {
+	sup: CoreIdx,
+	this: ObjValue,
+}
+impl SupThis {
+	pub fn has_super(&self) -> bool {
+		self.sup.super_exists()
 	}
-
-	fn this(&self) -> Option<ObjValue> {
-		Some(self.this.clone())
+	/// Implementation of `"field" in super` operation,
+	/// works faster than standalone super path.
+	///
+	/// In case of no `super` existence, returns false.
+	pub fn field_in_super(&self, field: IStr) -> bool {
+		self.this.has_field_include_hidden_idx(field, self.sup)
 	}
-
-	fn len(&self) -> usize {
-		self.inner.len()
+	/// Implementation of `super.field` operation,
+	/// works faster than standalone super path.
+	///
+	/// In case of no `super` existence, returns `NoSuperFound`
+	pub fn get_super(&self, field: IStr) -> Result<Option<Val>> {
+		if !self.sup.super_exists() {
+			bail!(NoSuperFound);
+		}
+		self.this.get_idx(field, self.sup)
 	}
-
-	fn is_empty(&self) -> bool {
-		self.inner.is_empty()
+	/// `super` with `self` overriden for top-level lookups.
+	/// Exists when super appears outside of `super.field`/`"field" in super` expressions
+	/// Exclusive to jrsonnet.
+	///
+	/// Might return `NoSuperFound` error.
+	pub fn standalone_super(&self) -> Result<ObjValue> {
+		if !self.sup.super_exists() {
+			bail!(NoSuperFound)
+		}
+		Ok(ObjValue::new(StandaloneSuperCore {
+			sup: self.sup,
+			this: self.this.clone(),
+		}))
 	}
-
-	fn enum_fields(&self, depth: SuperDepth, handler: &mut EnumFieldsHandler<'_>) -> bool {
-		self.inner.enum_fields(depth, handler)
+	pub fn this(&self) -> &ObjValue {
+		&self.this
 	}
-
-	fn has_field_include_hidden(&self, name: IStr) -> bool {
-		self.inner.has_field_include_hidden(name)
-	}
-
-	fn has_field(&self, name: IStr) -> bool {
-		self.inner.has_field(name)
+	pub fn downgrade(self) -> WeakSupThis {
+		WeakSupThis {
+			sup: self.sup,
+			this: self.this.downgrade(),
+		}
 	}
-
-	fn get_for(&self, key: IStr, this: ObjValue) -> Result<Option<Val>> {
-		self.inner.get_for(key, this)
-	}
-
-	fn get_for_uncached(&self, key: IStr, this: ObjValue) -> Result<Option<Val>> {
-		self.inner.get_raw(key, this)
-	}
-
-	fn field_visibility(&self, field: IStr) -> Option<Visibility> {
-		self.inner.field_visibility(field)
-	}
-
-	fn run_assertions_raw(&self, this: ObjValue) -> Result<()> {
-		self.inner.run_assertions_raw(this)
-	}
 }
+#[derive(Trace, PartialEq, Eq, Hash, Debug)]
+pub struct WeakSupThis {
+	sup: CoreIdx,
+	this: WeakObjValue,
+}
 
 impl ObjValue {
+	pub fn new(v: impl ObjectCore) -> Self {
+		Self(Cc::new(ObjValueInner {
+			cores: vec![ObjCore::new(v)],
+			assertions_ran: Cell::new(false),
+			value_cache: RefCell::new(FxHashMap::new()),
+		}))
+	}
 	pub fn new_empty() -> Self {
 		Self::new(EmptyObject)
 	}
@@ -363,27 +419,77 @@
 
 	#[must_use]
 	pub fn extend_from(&self, sup: Self) -> Self {
-		self.0.extend_from(sup)
+		let mut cores = sup.0.cores.clone();
+		cores.extend(self.0.cores.iter().cloned());
+		ObjValue(Cc::new(ObjValueInner {
+			cores,
+			value_cache: RefCell::default(),
+			assertions_ran: Cell::new(false),
+		}))
 	}
-	#[must_use]
-	pub fn with_this(&self, this: Self) -> Self {
-		self.0.with_this(self.clone(), this)
-	}
+	// #[must_use]
+	// pub fn with_this(&self, this: Self) -> Self {
+	// 	self.0.with_this(self.clone(), this)
+	// }
+	/// Returns amount of visible object fields
+	/// If object only contains hidden fields - may return zero.
 	pub fn len(&self) -> usize {
-		self.0.len()
+		self.fields_visibility()
+			.iter()
+			.filter(|(_, (visible, _))| *visible)
+			.count()
 	}
 	pub fn is_empty(&self) -> bool {
-		self.0.is_empty()
+		self.len() == 0
+	}
+	/// For each field, calls callback.
+	/// If callback returns false - ends iteration prematurely.
+	///
+	/// Returns false if ended prematurely
+	pub fn enum_fields(&self, handler: &mut EnumFieldsHandler<'_>) -> bool {
+		let mut super_depth = SuperDepth::default();
+		self.enum_fields_internal(
+			&mut super_depth,
+			handler,
+			CoreIdx {
+				idx: self.0.cores.len(),
+			},
+		)
 	}
-	pub fn enum_fields(&self, depth: SuperDepth, handler: &mut EnumFieldsHandler<'_>) -> bool {
-		self.0.enum_fields(depth, handler)
+	fn enum_fields_internal(
+		&self,
+		super_depth: &mut SuperDepth,
+		handler: &mut EnumFieldsHandler<'_>,
+		idx: CoreIdx,
+	) -> bool {
+		for core in self.0.cores[..idx.idx].iter() {
+			if !core.0.enum_fields_core(super_depth, handler) {
+				return false;
+			}
+			super_depth.deepen();
+		}
+		true
 	}
 
 	pub fn has_field_include_hidden(&self, name: IStr) -> bool {
-		self.0.has_field_include_hidden(name)
+		self.has_field_include_hidden_idx(
+			name,
+			CoreIdx {
+				idx: self.0.cores.len(),
+			},
+		)
+	}
+	fn has_field_include_hidden_idx(&self, name: IStr, core: CoreIdx) -> bool {
+		self.0.cores[..core.idx]
+			.iter()
+			.rev()
+			.any(|v| v.0.has_field_include_hidden(name.clone()))
 	}
 	pub fn has_field(&self, name: IStr) -> bool {
-		self.0.has_field(name)
+		match self.field_visibility(name) {
+			Some(Visibility::Unhide | Visibility::Normal) => true,
+			Some(Visibility::Hidden) | None => false,
+		}
 	}
 	pub fn has_field_ex(&self, name: IStr, include_hidden: bool) -> bool {
 		if include_hidden {
@@ -392,14 +498,78 @@
 			self.has_field(name)
 		}
 	}
+	pub fn get(&self, key: IStr) -> Result<Option<Val>> {
+		self.get_idx(
+			key,
+			CoreIdx {
+				idx: self.0.cores.len(),
+			},
+		)
+	}
 
-	pub fn get(&self, key: IStr) -> Result<Option<Val>> {
-		self.run_assertions()?;
-		self.get_for(key, self.0.this().unwrap_or_else(|| self.clone()))
+	fn get_idx(&self, key: IStr, core: CoreIdx) -> Result<Option<Val>> {
+		let cache_key = (key.clone(), core);
+		{
+			let mut cache = self.0.value_cache.borrow_mut();
+			// entry_ref candidate?
+			match cache.entry(cache_key.clone()) {
+				Entry::Occupied(v) => match v.get() {
+					CacheValue::Cached(v) => return v.clone(),
+					CacheValue::Pending => {
+						if !is_asserting(self) {
+							bail!(InfiniteRecursionDetected);
+						}
+					}
+				},
+				Entry::Vacant(v) => {
+					v.insert(CacheValue::Pending);
+				}
+			};
+		}
+		let result = self.get_idx_uncached(key, core);
+		{
+			let mut cache = self.0.value_cache.borrow_mut();
+			cache.insert(cache_key, CacheValue::Cached(result.clone()));
+		}
+		result
 	}
+	fn get_idx_uncached(&self, key: IStr, core: CoreIdx) -> Result<Option<Val>> {
+		self.run_assertions()?;
+		let mut add_stack = Vec::with_capacity(2);
+		for (sup, core) in self.0.cores[..core.idx].iter().enumerate().rev() {
+			let sup_this = SupThis {
+				sup: CoreIdx { idx: sup },
+				this: self.clone(),
+			};
+			if let Some((val, proc)) = core.0.get_for(key.clone(), sup_this)? {
+				match proc {
+					ValueProcess::None if add_stack.is_empty() => return Ok(Some(val)),
+					ValueProcess::None => {
+						add_stack.push(val);
+						break;
+					}
+					ValueProcess::SuperPlus => {
+						add_stack.push(val);
+					}
+				}
+			}
+		}
+		if add_stack.is_empty() {
+			// None of layers had this field
+			return Ok(None);
+		} else if add_stack.len() == 1 {
+			// A layer had this field, but it wanted this field to be added with super.
+			// However, no super had this field, fail-safe
+			return Ok(Some(add_stack.pop().expect("single element on stack")));
+		}
+		let mut values = add_stack.into_iter().rev();
+		let init = values.next().expect("at least 2 elements");
 
-	pub fn get_for(&self, key: IStr, this: Self) -> Result<Option<Val>> {
-		self.0.get_for(key, this)
+		values
+			.try_fold(init, |a, b| evaluate_add_op(&a, &b))
+			.map(Some)
+
+		// self.0.get_raw(key, this)
 	}
 
 	pub fn get_or_bail(&self, key: IStr) -> Result<Val> {
@@ -408,22 +578,48 @@
 			bail!(NoSuchField(key, suggestions))
 		};
 		Ok(value)
-	}
-
-	fn get_raw(&self, key: IStr, this: Self) -> Result<Option<Val>> {
-		self.0.get_for_uncached(key, this)
 	}
 
 	fn field_visibility(&self, field: IStr) -> Option<Visibility> {
-		self.0.field_visibility(field)
+		self.field_visibility_idx(
+			field,
+			CoreIdx {
+				idx: self.0.cores.len(),
+			},
+		)
 	}
+	fn field_visibility_idx(&self, field: IStr, core: CoreIdx) -> Option<Visibility> {
+		let mut exists = false;
+		for ele in self.0.cores[..core.idx].iter().rev() {
+			let vis = ele.0.field_visibility(field.clone());
+			match vis {
+				Some(Visibility::Unhide | Visibility::Hidden) => return vis,
+				Some(Visibility::Normal) => exists = true,
+				None => {}
+			}
+		}
+		exists.then_some(Visibility::Normal)
+	}
 
 	pub fn run_assertions(&self) -> Result<()> {
-		// FIXME: Should it use `self.0.this()` in case of standalone super?
-		self.run_assertions_raw(self.clone())
-	}
-	fn run_assertions_raw(&self, this: Self) -> Result<()> {
-		self.0.run_assertions_raw(this)
+		if self.0.assertions_ran.get() {
+			return Ok(());
+		}
+		if !start_asserting(self) {
+			return Ok(());
+		}
+		for (idx, ele) in self.0.cores.iter().enumerate() {
+			let sup_this = SupThis {
+				sup: CoreIdx { idx },
+				this: self.clone(),
+			};
+			ele.0.run_assertions_raw(sup_this).inspect_err(|_e| {
+				finish_asserting(self);
+			})?;
+		}
+		finish_asserting(self);
+		self.0.assertions_ran.set(true);
+		Ok(())
 	}
 
 	pub fn iter(
@@ -462,24 +658,22 @@
 	}
 	fn fields_visibility(&self) -> FxHashMap<IStr, (bool, FieldSortKey)> {
 		let mut out = FxHashMap::default();
-		self.enum_fields(
-			SuperDepth::default(),
-			&mut |depth, index, name, visibility| {
-				let new_sort_key = FieldSortKey::new(depth, index);
-				let entry = out.entry(name);
-				let (visible, _) = entry.or_insert((true, new_sort_key));
-				match visibility {
-					Visibility::Normal => {}
-					Visibility::Hidden => {
-						*visible = false;
-					}
-					Visibility::Unhide => {
-						*visible = true;
-					}
-				};
-				false
-			},
-		);
+		self.enum_fields(&mut |depth, index, name, visibility| {
+			dbg!(&name, visibility);
+			let new_sort_key = FieldSortKey::new(depth, index);
+			let entry = out.entry(name);
+			let (visible, _) = entry.or_insert((true, new_sort_key));
+			match visibility {
+				Visibility::Normal => {}
+				Visibility::Hidden => {
+					*visible = false;
+				}
+				Visibility::Unhide => {
+					*visible = true;
+				}
+			};
+			false
+		});
 		out
 	}
 	pub fn fields_ex(
@@ -515,8 +709,8 @@
 			return fields;
 		}
 
-		let mut fields: Vec<_> = self
-			.fields_visibility()
+		let mut fields: Vec<_> = dbg!(self
+			.fields_visibility())
 			.into_iter()
 			.filter(|(_, (visible, _))| include_hidden || *visible)
 			.map(|(k, _)| k)
@@ -580,210 +774,65 @@
 
 impl OopObject {
 	pub fn new(
-		sup: Option<ObjValue>,
 		this_entries: Cc<FxHashMap<IStr, ObjMember>>,
 		assertions: Cc<Vec<CcObjectAssertion>>,
 	) -> Self {
 		Self {
-			sup,
-			// this: None,
-			assertions,
-			assertions_ran: RefCell::new(FxHashSet::new()),
 			this_entries,
 			value_cache: RefCell::new(FxHashMap::new()),
+			assertions,
 		}
 	}
-
-	fn evaluate_this(&self, v: &ObjMember, real_this: ObjValue) -> Result<Val> {
-		v.invoke.evaluate(self.sup.clone(), Some(real_this))
-	}
-
-	// FIXME: Duplication between ObjValue and OopObject
-	fn fields_visibility(&self) -> FxHashMap<IStr, (bool, FieldSortKey)> {
-		let mut out = FxHashMap::default();
-		self.enum_fields(
-			SuperDepth::default(),
-			&mut |depth, index, name, visibility| {
-				let new_sort_key = FieldSortKey::new(depth, index);
-				let entry = out.entry(name);
-				let (visible, _) = entry.or_insert((true, new_sort_key));
-				match visibility {
-					Visibility::Normal => {}
-					Visibility::Hidden => {
-						*visible = false;
-					}
-					Visibility::Unhide => {
-						*visible = true;
-					}
-				};
-				false
-			},
-		);
-		out
-	}
 }
 
-impl ObjectLike for OopObject {
-	fn extend_from(&self, sup: ObjValue) -> ObjValue {
-		ObjValue::new(match &self.sup {
-			None => Self::new(
-				Some(sup),
-				self.this_entries.clone(),
-				self.assertions.clone(),
-			),
-			Some(v) => Self::new(
-				Some(v.extend_from(sup)),
-				self.this_entries.clone(),
-				self.assertions.clone(),
-			),
-		})
-	}
-
-	fn len(&self) -> usize {
-		// Maybe it will be better to not compute sort key here?
-		self.fields_visibility()
-			.into_iter()
-			.filter(|(_, (visible, _))| *visible)
-			.count()
-	}
-
-	/// Returns false only if there is any visible entry.
-	///
-	/// Note that object with hidden fields `{a:: 1}` will be reported as empty here.
-	fn is_empty(&self) -> bool {
-		self.len() == 0
-	}
-
-	/// Run callback for every field found in object
-	///
-	/// Returns true if ended prematurely
-	fn enum_fields(&self, depth: SuperDepth, handler: &mut EnumFieldsHandler<'_>) -> bool {
-		if let Some(s) = &self.sup {
-			if s.enum_fields(depth.deeper(), handler) {
-				return true;
-			}
-		}
+impl ObjectCore for OopObject {
+	fn enum_fields_core(
+		&self,
+		super_depth: &mut SuperDepth,
+		handler: &mut EnumFieldsHandler<'_>,
+	) -> bool {
 		for (name, member) in self.this_entries.iter() {
 			if handler(
-				depth,
+				*super_depth,
 				member.original_index,
 				name.clone(),
 				member.flags.visibility(),
 			) {
-				return true;
+				return false;
 			}
 		}
-		false
+		true
 	}
 
 	fn has_field_include_hidden(&self, name: IStr) -> bool {
-		if self.this_entries.contains_key(&name) {
-			true
-		} else if let Some(super_obj) = &self.sup {
-			super_obj.has_field_include_hidden(name)
-		} else {
-			false
-		}
+		self.this_entries.contains_key(&name)
 	}
-	fn has_field(&self, name: IStr) -> bool {
-		self.field_visibility(name)
-			.map_or(false, |v| v.is_visible())
-	}
 
-	fn get_for(&self, key: IStr, this: ObjValue) -> Result<Option<Val>> {
-		let cache_key = (key.clone(), Some(this.clone().downgrade()));
-		if let Some(v) = self.value_cache.borrow().get(&cache_key) {
-			return Ok(match v {
-				CacheValue::Cached(v) => Some(v.clone()),
-				CacheValue::NotFound => None,
-				CacheValue::Pending => bail!(InfiniteRecursionDetected),
-				CacheValue::Errored(e) => return Err(e.clone()),
-			});
-		}
-		self.value_cache
-			.borrow_mut()
-			.insert(cache_key.clone(), CacheValue::Pending);
-		let value = self.get_for_uncached(key, this).inspect_err(|e| {
-			self.value_cache
-				.borrow_mut()
-				.insert(cache_key.clone(), CacheValue::Errored(e.clone()));
-		})?;
-		self.value_cache.borrow_mut().insert(
-			cache_key,
-			value
-				.as_ref()
-				.map_or(CacheValue::NotFound, |v| CacheValue::Cached(v.clone())),
-		);
-		Ok(value)
-	}
-	fn get_for_uncached(&self, key: IStr, real_this: ObjValue) -> Result<Option<Val>> {
-		match (self.this_entries.get(&key), &self.sup) {
-			(Some(k), None) => Ok(Some(self.evaluate_this(k, real_this)?)),
-			(Some(k), Some(super_obj)) => {
-				let our = self.evaluate_this(k, real_this.clone())?;
+	fn get_for(&self, key: IStr, sup_this: SupThis) -> Result<Option<(Val, ValueProcess)>> {
+		match self.this_entries.get(&key) {
+			Some(k) => Ok(Some((
+				k.invoke.evaluate(sup_this)?,
 				if k.flags.add() {
-					super_obj
-						.get_raw(key, real_this)?
-						.map_or(Ok(Some(our.clone())), |v| {
-							Ok(Some(evaluate_add_op(&v, &our)?))
-						})
+					ValueProcess::SuperPlus
 				} else {
-					Ok(Some(our))
-				}
-			}
-			(None, Some(super_obj)) => super_obj.get_raw(key, real_this),
-			(None, None) => Ok(None),
+					ValueProcess::None
+				},
+			))),
+			None => Ok(None),
 		}
 	}
 	fn field_visibility(&self, name: IStr) -> Option<Visibility> {
-		if let Some(m) = self.this_entries.get(&name) {
-			Some(match &m.flags.visibility() {
-				Visibility::Normal => self
-					.sup
-					.as_ref()
-					.and_then(|super_obj| super_obj.field_visibility(name))
-					.unwrap_or(Visibility::Normal),
-				v => *v,
-			})
-		} else if let Some(super_obj) = &self.sup {
-			super_obj.field_visibility(name)
-		} else {
-			None
-		}
+		Some(self.this_entries.get(&name)?.flags.visibility())
 	}
 
-	fn run_assertions_raw(&self, real_this: ObjValue) -> Result<()> {
+	fn run_assertions_raw(&self, sup_this: SupThis) -> Result<()> {
 		if self.assertions.is_empty() {
-			if let Some(super_obj) = &self.sup {
-				super_obj.run_assertions_raw(real_this)?;
-			}
 			return Ok(());
 		}
-		if self.assertions_ran.borrow_mut().insert(real_this.clone()) {
-			for assertion in self.assertions.iter() {
-				if let Err(e) = assertion.0.run(self.sup.clone(), Some(real_this.clone())) {
-					self.assertions_ran.borrow_mut().remove(&real_this);
-					return Err(e);
-				}
-			}
-			if let Some(super_obj) = &self.sup {
-				super_obj.run_assertions_raw(real_this)?;
-			}
+		for assertion in self.assertions.iter() {
+			assertion.0.run(sup_this.clone())?;
 		}
 		Ok(())
-	}
-}
-
-impl PartialEq for ObjValue {
-	fn eq(&self, other: &Self) -> bool {
-		Cc::ptr_eq(&self.0, &other.0)
-	}
-}
-
-impl Eq for ObjValue {}
-impl Hash for ObjValue {
-	fn hash<H: Hasher>(&self, hasher: &mut H) {
-		hasher.write_usize(addr_of!(*self.0).expose_provenance() as usize);
 	}
 }
 
@@ -845,11 +894,8 @@
 		if self.sup.is_none() && self.map.is_empty() && self.assertions.is_empty() {
 			return ObjValue::new_empty();
 		}
-		ObjValue::new(OopObject::new(
-			self.sup,
-			Cc::new(self.map),
-			Cc::new(self.assertions),
-		))
+		let res = ObjValue::new(OopObject::new(Cc::new(self.map), Cc::new(self.assertions)));
+		self.sup.map(|sup| res.extend_from(sup)).unwrap_or(res)
 	}
 }
 impl Default for ObjValueBuilder {