diff --git a/Cargo.lock b/Cargo.lock
index 024eb4021..2f7d8207a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1390,10 +1390,6 @@ dependencies = [
  "either",
 ]
 
-[[package]]
-name = "iterutil"
-version = "0.0.94"
-
 [[package]]
 name = "itoa"
 version = "1.0.10"
@@ -2269,7 +2265,6 @@ dependencies = [
  "half",
  "hashbrown 0.14.5",
  "indexmap",
- "iterutil",
  "num",
  "num-traits",
  "num_cpus",
@@ -2288,6 +2283,7 @@ dependencies = [
  "serde_json",
  "similar-asserts",
  "smallvec",
+ "stdutil",
  "strsim",
  "textwrap",
  "tokio",
@@ -3036,6 +3032,10 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
 
+[[package]]
+name = "stdutil"
+version = "0.0.94"
+
 [[package]]
 name = "stringprep"
 version = "0.1.5"
diff --git a/crates/rayexec_execution/Cargo.toml b/crates/rayexec_execution/Cargo.toml
index f895cb44a..bb23dab95 100644
--- a/crates/rayexec_execution/Cargo.toml
+++ b/crates/rayexec_execution/Cargo.toml
@@ -10,7 +10,7 @@ rayexec_parser = { path = "../rayexec_parser" }
 # rayexec_bullet = { path = "../rayexec_bullet" }
 rayexec_io = { path = "../rayexec_io" }
 fmtutil = { path = "../fmtutil" }
-iterutil = { path = "../iterutil" }
+stdutil = { path = "../stdutil" }
 # stackutil = { path = "../stackutil" } TODO: psm hash issues when compiling to wasm on macos
 
 ahash = { workspace = true }
diff --git a/crates/rayexec_execution/src/arrays/array/exp.rs b/crates/rayexec_execution/src/arrays/array/exp.rs
index 3e106d0ba..adee68af3 100644
--- a/crates/rayexec_execution/src/arrays/array/exp.rs
+++ b/crates/rayexec_execution/src/arrays/array/exp.rs
@@ -1,6 +1,6 @@
 use half::f16;
-use iterutil::{IntoExactSizeIterator, TryFromExactSizeIterator};
 use rayexec_error::{not_implemented, RayexecError, Result};
+use stdutil::iter::{IntoExactSizeIterator, TryFromExactSizeIterator};
 
 use super::array_data::ArrayData;
 use super::flat::FlatArrayView;
diff --git a/crates/rayexec_execution/src/arrays/batch_exp.rs b/crates/rayexec_execution/src/arrays/batch_exp.rs
index 7405a372e..0888785ff 100644
--- a/crates/rayexec_execution/src/arrays/batch_exp.rs
+++ b/crates/rayexec_execution/src/arrays/batch_exp.rs
@@ -1,5 +1,5 @@
-use iterutil::IntoExactSizeIterator;
 use rayexec_error::{RayexecError, Result};
+use stdutil::iter::IntoExactSizeIterator;
 
 use super::array::exp::Array;
 use super::array::selection::Selection;
@@ -139,7 +139,7 @@ where
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
 
diff --git a/crates/rayexec_execution/src/arrays/compute/cast/array.rs b/crates/rayexec_execution/src/arrays/compute/cast/array.rs
index 2de9f9731..2156a127f 100644
--- a/crates/rayexec_execution/src/arrays/compute/cast/array.rs
+++ b/crates/rayexec_execution/src/arrays/compute/cast/array.rs
@@ -1,6 +1,6 @@
 use std::ops::Mul;
 
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use num::{CheckedDiv, CheckedMul, Float, NumCast, PrimInt, ToPrimitive};
 use rayexec_error::{RayexecError, Result};
 
@@ -840,7 +840,7 @@ where
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::datatype::DecimalTypeMeta;
diff --git a/crates/rayexec_execution/src/arrays/compute/date.rs b/crates/rayexec_execution/src/arrays/compute/date.rs
index 255fec887..a9c4213a1 100644
--- a/crates/rayexec_execution/src/arrays/compute/date.rs
+++ b/crates/rayexec_execution/src/arrays/compute/date.rs
@@ -1,5 +1,5 @@
 use chrono::{DateTime, Datelike, NaiveDate, Timelike, Utc};
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use rayexec_error::{not_implemented, RayexecError, Result};
 
 use crate::arrays::array::exp::Array;
diff --git a/crates/rayexec_execution/src/arrays/executor_exp/aggregate/binary.rs b/crates/rayexec_execution/src/arrays/executor_exp/aggregate/binary.rs
index 71d1c6b0e..139cb5652 100644
--- a/crates/rayexec_execution/src/arrays/executor_exp/aggregate/binary.rs
+++ b/crates/rayexec_execution/src/arrays/executor_exp/aggregate/binary.rs
@@ -1,5 +1,5 @@
-use iterutil::IntoExactSizeIterator;
 use rayexec_error::Result;
+use stdutil::iter::IntoExactSizeIterator;
 
 use super::AggregateState;
 use crate::arrays::array::exp::Array;
@@ -62,7 +62,7 @@ impl BinaryNonNullUpdater {
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::buffer::physical_type::{AddressableMut, PhysicalI32};
diff --git a/crates/rayexec_execution/src/arrays/executor_exp/aggregate/mod.rs b/crates/rayexec_execution/src/arrays/executor_exp/aggregate/mod.rs
index f836c670d..443ad1874 100644
--- a/crates/rayexec_execution/src/arrays/executor_exp/aggregate/mod.rs
+++ b/crates/rayexec_execution/src/arrays/executor_exp/aggregate/mod.rs
@@ -40,6 +40,7 @@ impl StateCombiner {
     ) -> Result<()>
     where
         State: AggregateState<Input, Output>,
+        Output: ?Sized,
     {
         for (from, to) in mapping {
             let consume = &mut consume[from];
diff --git a/crates/rayexec_execution/src/arrays/executor_exp/aggregate/unary.rs b/crates/rayexec_execution/src/arrays/executor_exp/aggregate/unary.rs
index 2532e9d65..463b568af 100644
--- a/crates/rayexec_execution/src/arrays/executor_exp/aggregate/unary.rs
+++ b/crates/rayexec_execution/src/arrays/executor_exp/aggregate/unary.rs
@@ -1,5 +1,5 @@
-use iterutil::IntoExactSizeIterator;
 use rayexec_error::Result;
+use stdutil::iter::IntoExactSizeIterator;
 
 use super::AggregateState;
 use crate::arrays::array::exp::Array;
@@ -94,7 +94,7 @@ impl UnaryNonNullUpdater {
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::buffer::buffer_manager::NopBufferManager;
diff --git a/crates/rayexec_execution/src/arrays/executor_exp/scalar/binary.rs b/crates/rayexec_execution/src/arrays/executor_exp/scalar/binary.rs
index 3764884f1..894a56487 100644
--- a/crates/rayexec_execution/src/arrays/executor_exp/scalar/binary.rs
+++ b/crates/rayexec_execution/src/arrays/executor_exp/scalar/binary.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use rayexec_error::Result;
 
 use crate::arrays::array::exp::Array;
@@ -144,7 +144,7 @@ impl BinaryExecutor {
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::array::validity::Validity;
diff --git a/crates/rayexec_execution/src/arrays/executor_exp/scalar/list_reduce.rs b/crates/rayexec_execution/src/arrays/executor_exp/scalar/list_reduce.rs
index a1860e6e2..c552c0161 100644
--- a/crates/rayexec_execution/src/arrays/executor_exp/scalar/list_reduce.rs
+++ b/crates/rayexec_execution/src/arrays/executor_exp/scalar/list_reduce.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use rayexec_error::{RayexecError, Result};
 
 use crate::arrays::array::exp::Array;
diff --git a/crates/rayexec_execution/src/arrays/executor_exp/scalar/ternary.rs b/crates/rayexec_execution/src/arrays/executor_exp/scalar/ternary.rs
index 179be7a19..49599c903 100644
--- a/crates/rayexec_execution/src/arrays/executor_exp/scalar/ternary.rs
+++ b/crates/rayexec_execution/src/arrays/executor_exp/scalar/ternary.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use rayexec_error::Result;
 
 use crate::arrays::array::exp::Array;
@@ -189,7 +189,7 @@ impl TernaryExecutor {
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::buffer::buffer_manager::NopBufferManager;
diff --git a/crates/rayexec_execution/src/arrays/executor_exp/scalar/unary.rs b/crates/rayexec_execution/src/arrays/executor_exp/scalar/unary.rs
index 67f6a39cc..3e2f62a92 100644
--- a/crates/rayexec_execution/src/arrays/executor_exp/scalar/unary.rs
+++ b/crates/rayexec_execution/src/arrays/executor_exp/scalar/unary.rs
@@ -1,5 +1,5 @@
-use iterutil::IntoExactSizeIterator;
 use rayexec_error::Result;
+use stdutil::iter::IntoExactSizeIterator;
 
 use crate::arrays::array::exp::Array;
 use crate::arrays::array::flat::FlatArrayView;
@@ -179,7 +179,7 @@ impl UnaryExecutor {
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::array::validity::Validity;
diff --git a/crates/rayexec_execution/src/arrays/executor_exp/scalar/uniform.rs b/crates/rayexec_execution/src/arrays/executor_exp/scalar/uniform.rs
index 08092741a..d45f71741 100644
--- a/crates/rayexec_execution/src/arrays/executor_exp/scalar/uniform.rs
+++ b/crates/rayexec_execution/src/arrays/executor_exp/scalar/uniform.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use rayexec_error::Result;
 
 use crate::arrays::array::exp::Array;
@@ -149,7 +149,7 @@ impl UniformExecutor {
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::buffer::buffer_manager::NopBufferManager;
diff --git a/crates/rayexec_execution/src/arrays/testutil.rs b/crates/rayexec_execution/src/arrays/testutil.rs
index 8492dc81f..988e760ec 100644
--- a/crates/rayexec_execution/src/arrays/testutil.rs
+++ b/crates/rayexec_execution/src/arrays/testutil.rs
@@ -8,7 +8,7 @@
 use std::collections::BTreeMap;
 use std::fmt::Debug;
 
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 
 use super::array::exp::Array;
 use super::batch_exp::Batch;
@@ -201,7 +201,7 @@ pub fn assert_batches_eq(batch1: &Batch, batch2: &Batch) {
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::buffer::buffer_manager::NopBufferManager;
diff --git a/crates/rayexec_execution/src/expr/physical/case_expr.rs b/crates/rayexec_execution/src/expr/physical/case_expr.rs
index 45b74cafe..48a4c78b4 100644
--- a/crates/rayexec_execution/src/expr/physical/case_expr.rs
+++ b/crates/rayexec_execution/src/expr/physical/case_expr.rs
@@ -187,7 +187,7 @@ impl fmt::Display for PhysicalCaseExpr {
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::datatype::DataType;
diff --git a/crates/rayexec_execution/src/expr/physical/cast_expr.rs b/crates/rayexec_execution/src/expr/physical/cast_expr.rs
index 2c4a56c41..729e3f7e8 100644
--- a/crates/rayexec_execution/src/expr/physical/cast_expr.rs
+++ b/crates/rayexec_execution/src/expr/physical/cast_expr.rs
@@ -101,7 +101,7 @@ impl DatabaseProtoConv for PhysicalCastExpr {
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::buffer::buffer_manager::NopBufferManager;
diff --git a/crates/rayexec_execution/src/expr/physical/column_expr.rs b/crates/rayexec_execution/src/expr/physical/column_expr.rs
index 6280eabb0..40537bc5f 100644
--- a/crates/rayexec_execution/src/expr/physical/column_expr.rs
+++ b/crates/rayexec_execution/src/expr/physical/column_expr.rs
@@ -70,7 +70,7 @@ impl DatabaseProtoConv for PhysicalColumnExpr {
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::datatype::DataType;
diff --git a/crates/rayexec_execution/src/expr/physical/literal_expr.rs b/crates/rayexec_execution/src/expr/physical/literal_expr.rs
index f220d8fbe..a35bced6e 100644
--- a/crates/rayexec_execution/src/expr/physical/literal_expr.rs
+++ b/crates/rayexec_execution/src/expr/physical/literal_expr.rs
@@ -68,7 +68,7 @@ impl DatabaseProtoConv for PhysicalLiteralExpr {
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::datatype::DataType;
diff --git a/crates/rayexec_execution/src/functions/aggregate/states.rs b/crates/rayexec_execution/src/functions/aggregate/states.rs
index f1416fc07..808218e32 100644
--- a/crates/rayexec_execution/src/functions/aggregate/states.rs
+++ b/crates/rayexec_execution/src/functions/aggregate/states.rs
@@ -3,8 +3,9 @@ use std::any::Any;
 use std::fmt::Debug;
 use std::marker::PhantomData;
 
-use iterutil::IntoExactSizeIterator;
 use rayexec_error::{RayexecError, Result};
+use stdutil::iter::IntoExactSizeIterator;
+use stdutil::marker::PhantomCovariant;
 
 use super::ChunkGroupAddressIter;
 use crate::arrays::array::exp::Array;
@@ -32,7 +33,14 @@ use crate::arrays::executor_exp::aggregate::{AggregateState, StateCombiner};
 use crate::arrays::executor_exp::PutBuffer;
 use crate::arrays::storage::{AddressableStorage, PrimitiveStorage};
 
-pub struct TypedAggregateGroupStates<State, Input, Output, StateInit, StateUpdate, StateFinalize> {
+pub struct TypedAggregateGroupStates<
+    State,
+    Input,
+    Output: ?Sized,
+    StateInit,
+    StateUpdate,
+    StateFinalize,
+> {
     /// States being tracked.
     states: Vec<State>,
 
@@ -47,11 +55,11 @@ pub struct TypedAggregateGroupStates<State, Input, Output, StateInit, StateUpdat
     /// How to finalize states.
     state_finalize: StateFinalize,
 
-    _input: PhantomData<Input>,
-    _output: PhantomData<Output>,
+    _input: PhantomCovariant<Input>,
+    _output: PhantomCovariant<Output>,
 }
 
-impl<State, Input, Output, StateInit, StateUpdate, StateFinalize>
+impl<State, Input, Output: ?Sized, StateInit, StateUpdate, StateFinalize>
     TypedAggregateGroupStates<State, Input, Output, StateInit, StateUpdate, StateFinalize>
 {
     pub fn new(
@@ -65,8 +73,8 @@ impl<State, Input, Output, StateInit, StateUpdate, StateFinalize>
             state_init,
             state_update,
             state_finalize,
-            _input: PhantomData,
-            _output: PhantomData,
+            _input: PhantomCovariant::new(),
+            _output: PhantomCovariant::new(),
         }
     }
 }
@@ -76,7 +84,7 @@ impl<State, Input, Output, StateInit, StateUpdate, StateFinalize> AggregateGroup
 where
     State: AggregateState<Input, Output> + Sync + Send + 'static,
     Input: Sync + Send,
-    Output: Sync + Send,
+    Output: Sync + Send + ?Sized,
     StateInit: Fn() -> State + Sync + Send,
     StateUpdate: Fn(&[Array], Selection, &[usize], &mut [State]) -> Result<()> + Sync + Send,
     StateFinalize: Fn(&mut [State], &mut Array) -> Result<()> + Sync + Send,
@@ -155,7 +163,7 @@ where
     Ok(())
 }
 
-impl<State, Input, Output, StateInit, StateUpdate, StateFinalize> fmt::Debug
+impl<State, Input, Output: ?Sized, StateInit, StateUpdate, StateFinalize> fmt::Debug
     for TypedAggregateGroupStates<State, Input, Output, StateInit, StateUpdate, StateFinalize>
 {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/arith/add.rs b/crates/rayexec_execution/src/functions/scalar/builtin/arith/add.rs
index 4d97b33e4..fa67ea729 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/arith/add.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/arith/add.rs
@@ -204,7 +204,7 @@ where
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::buffer::buffer_manager::NopBufferManager;
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/arith/div.rs b/crates/rayexec_execution/src/functions/scalar/builtin/arith/div.rs
index 596dd83fd..76a56409c 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/arith/div.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/arith/div.rs
@@ -251,7 +251,7 @@ where
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::buffer::buffer_manager::NopBufferManager;
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/arith/mul.rs b/crates/rayexec_execution/src/functions/scalar/builtin/arith/mul.rs
index a657354a4..4edbfbe1d 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/arith/mul.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/arith/mul.rs
@@ -317,7 +317,7 @@ where
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::buffer::buffer_manager::NopBufferManager;
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/arith/rem.rs b/crates/rayexec_execution/src/functions/scalar/builtin/arith/rem.rs
index 7f151e9b4..f7c590704 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/arith/rem.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/arith/rem.rs
@@ -200,7 +200,7 @@ where
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::buffer::buffer_manager::NopBufferManager;
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/arith/sub.rs b/crates/rayexec_execution/src/functions/scalar/builtin/arith/sub.rs
index 5157ac36c..fc00d326c 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/arith/sub.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/arith/sub.rs
@@ -212,7 +212,7 @@ where
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::buffer::buffer_manager::NopBufferManager;
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/boolean.rs b/crates/rayexec_execution/src/functions/scalar/builtin/boolean.rs
index 4ec43590c..c9d3cc7e8 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/boolean.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/boolean.rs
@@ -225,7 +225,7 @@ impl ScalarFunctionImpl for OrImpl {
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::buffer::buffer_manager::NopBufferManager;
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/comparison.rs b/crates/rayexec_execution/src/functions/scalar/builtin/comparison.rs
index 7b6018a0a..99be81f0c 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/comparison.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/comparison.rs
@@ -854,7 +854,7 @@ where
 #[cfg(test)]
 mod tests {
 
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::buffer::buffer_manager::NopBufferManager;
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/datetime/epoch.rs b/crates/rayexec_execution/src/functions/scalar/builtin/datetime/epoch.rs
index 42b444978..3ce6a16ee 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/datetime/epoch.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/datetime/epoch.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use rayexec_error::Result;
 
 use crate::arrays::array::exp::Array;
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/is.rs b/crates/rayexec_execution/src/functions/scalar/builtin/is.rs
index 9aab1b382..888bd0b2b 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/is.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/is.rs
@@ -337,7 +337,7 @@ impl<const NOT: bool, const BOOL: bool> ScalarFunctionImpl for CheckBoolImpl<NOT
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::buffer::buffer_manager::NopBufferManager;
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/list/list_extract.rs b/crates/rayexec_execution/src/functions/scalar/builtin/list/list_extract.rs
index 2e846f6b4..89773eb85 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/list/list_extract.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/list/list_extract.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use rayexec_error::{not_implemented, RayexecError, Result};
 
 use crate::arrays::array::exp::Array;
@@ -209,7 +209,7 @@ where
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::buffer::buffer_manager::NopBufferManager;
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/list/list_values.rs b/crates/rayexec_execution/src/functions/scalar/builtin/list/list_values.rs
index 13e3bc258..63ea2dbdd 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/list/list_values.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/list/list_values.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use rayexec_error::{not_implemented, RayexecError, Result};
 
 use crate::arrays::array::exp::Array;
@@ -234,7 +234,7 @@ fn list_values_inner<S: MutablePhysicalStorage>(
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::buffer::physical_type::PhysicalStorage;
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/abs.rs b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/abs.rs
index d2ffb9b58..be949b68f 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/abs.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/abs.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use num_traits::Float;
 use rayexec_error::Result;
 
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/acos.rs b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/acos.rs
index cd3f9f61e..46b26bdec 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/acos.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/acos.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use num_traits::Float;
 use rayexec_error::Result;
 
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/asin.rs b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/asin.rs
index 48aec0004..6c1ddc6d5 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/asin.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/asin.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use num_traits::Float;
 use rayexec_error::Result;
 
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/atan.rs b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/atan.rs
index 57b043d97..61a4ab7c1 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/atan.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/atan.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use num_traits::Float;
 use rayexec_error::Result;
 
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/cbrt.rs b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/cbrt.rs
index 6869f7fc4..ee6979ac0 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/cbrt.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/cbrt.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use num_traits::Float;
 use rayexec_error::Result;
 
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/ceil.rs b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/ceil.rs
index 5a2c5bd99..b439a0f02 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/ceil.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/ceil.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use num_traits::Float;
 use rayexec_error::Result;
 
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/cos.rs b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/cos.rs
index 7be1dbf36..bc3c36af1 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/cos.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/cos.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use num_traits::Float;
 use rayexec_error::Result;
 
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/degrees.rs b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/degrees.rs
index 1024e2db1..b79f51c4a 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/degrees.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/degrees.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use num_traits::Float;
 use rayexec_error::Result;
 
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/exp.rs b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/exp.rs
index 7d3ff3fb5..649b8c3bf 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/exp.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/exp.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use num_traits::Float;
 use rayexec_error::Result;
 
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/floor.rs b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/floor.rs
index b1b7d9611..c47e8ba09 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/floor.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/floor.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use num_traits::Float;
 use rayexec_error::Result;
 
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/ln.rs b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/ln.rs
index 38ab5ba16..5650abb5e 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/ln.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/ln.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use num_traits::Float;
 use rayexec_error::Result;
 
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/log.rs b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/log.rs
index 9c4cbdeb0..cb9c9ccec 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/log.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/log.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use num_traits::Float;
 use rayexec_error::Result;
 
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/mod.rs b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/mod.rs
index 95310d2ce..a28318491 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/mod.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/mod.rs
@@ -29,7 +29,7 @@ pub use degrees::*;
 pub use exp::*;
 pub use floor::*;
 pub use isnan::*;
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 pub use ln::*;
 pub use log::*;
 use num_traits::Float;
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/radians.rs b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/radians.rs
index 41305b084..86e94812c 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/radians.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/radians.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use num_traits::Float;
 use rayexec_error::Result;
 
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/sin.rs b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/sin.rs
index 1c6aefbe3..592a1a090 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/sin.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/sin.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use num_traits::Float;
 use rayexec_error::Result;
 
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/sqrt.rs b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/sqrt.rs
index b2b33cc7c..c0c3f58e2 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/sqrt.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/sqrt.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use num_traits::Float;
 use rayexec_error::Result;
 
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/tan.rs b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/tan.rs
index 0d92567d2..3392fe201 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/numeric/tan.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/numeric/tan.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use num_traits::Float;
 use rayexec_error::Result;
 
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/similarity/l2_distance.rs b/crates/rayexec_execution/src/functions/scalar/builtin/similarity/l2_distance.rs
index 14f62a52a..857a093f7 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/similarity/l2_distance.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/similarity/l2_distance.rs
@@ -149,7 +149,7 @@ where
 
 #[cfg(test)]
 mod tests {
-    use iterutil::TryFromExactSizeIterator;
+    use stdutil::iter::TryFromExactSizeIterator;
 
     use super::*;
     use crate::arrays::buffer::buffer_manager::NopBufferManager;
diff --git a/crates/rayexec_execution/src/functions/scalar/builtin/string/case.rs b/crates/rayexec_execution/src/functions/scalar/builtin/string/case.rs
index 016a7ad79..47f4f47fd 100644
--- a/crates/rayexec_execution/src/functions/scalar/builtin/string/case.rs
+++ b/crates/rayexec_execution/src/functions/scalar/builtin/string/case.rs
@@ -1,4 +1,4 @@
-use iterutil::IntoExactSizeIterator;
+use stdutil::iter::IntoExactSizeIterator;
 use rayexec_error::Result;
 
 use crate::arrays::array::exp::Array;
diff --git a/crates/iterutil/Cargo.toml b/crates/stdutil/Cargo.toml
similarity index 80%
rename from crates/iterutil/Cargo.toml
rename to crates/stdutil/Cargo.toml
index 39c919663..7cb3e1417 100644
--- a/crates/iterutil/Cargo.toml
+++ b/crates/stdutil/Cargo.toml
@@ -1,5 +1,5 @@
 [package]
-name = "iterutil"
+name = "stdutil"
 version.workspace = true
 edition.workspace = true
 
diff --git a/crates/iterutil/src/lib.rs b/crates/stdutil/src/iter.rs
similarity index 100%
rename from crates/iterutil/src/lib.rs
rename to crates/stdutil/src/iter.rs
diff --git a/crates/stdutil/src/lib.rs b/crates/stdutil/src/lib.rs
new file mode 100644
index 000000000..854431330
--- /dev/null
+++ b/crates/stdutil/src/lib.rs
@@ -0,0 +1,4 @@
+//! Utilities that are closely related to items found in std.
+
+pub mod iter;
+pub mod marker;
diff --git a/crates/stdutil/src/marker.rs b/crates/stdutil/src/marker.rs
new file mode 100644
index 000000000..27a8868b4
--- /dev/null
+++ b/crates/stdutil/src/marker.rs
@@ -0,0 +1,22 @@
+use std::marker::PhantomData;
+
+/// Marker type that indicates covariance of `T` but does not inherit the bounds
+/// of `T`.
+///
+/// Has all the same properties of `PhantomData` minus the inherited trait
+/// bounds. This lets us make structs and other types covariant to `T` but
+/// without the potential inheritence of `?Sized` (or other undesired traits) in
+/// the outer type.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct PhantomCovariant<T>(PhantomData<fn() -> T>)
+where
+    T: ?Sized;
+
+impl<T> PhantomCovariant<T>
+where
+    T: ?Sized,
+{
+    pub const fn new() -> Self {
+        PhantomCovariant(PhantomData)
+    }
+}