Implement shared values for rust-transient-0

5 files changed, 462 insertions, 139 deletions

diff --git a/examples/11-transient-0/output/rust/src/gen/data/transient_0.rs b/examples/11-transient-0/output/rust/src/gen/data/transient_0.rs
index cffb318..6ee8baf 100644
--- a/examples/11-transient-0/output/rust/src/gen/data/transient_0.rs
+++ b/examples/11-transient-0/output/rust/src/gen/data/transient_0.rs
@@ -1,136 +1,136 @@
 // Generated by hobgoblin.
 
-pub fn encode_struct_with_bool(value: &crate::data::StructWithBool, writer: &mut impl std::io::Write) -> ::std::io::Result::<()> {
-    crate::transient_0::encode_bool(&value.a, writer)?;
-    crate::transient_0::encode_bool(&value.b, writer)?;
+pub fn encode_struct_with_bool(value: &crate::data::StructWithBool, writer: &mut impl std::io::Write, shared_values: &mut ::std::collections::HashMap::<::core::primitive::usize, ::core::primitive::i64>) -> ::std::io::Result::<()> {
+    crate::transient_0::encode_bool(&value.a, writer, shared_values)?;
+    crate::transient_0::encode_bool(&value.b, writer, shared_values)?;
     ::std::io::Result::Ok(())
 }
 
-pub fn decode_struct_with_bool(reader: &mut impl std::io::Read) -> ::std::io::Result::<crate::data::StructWithBool> {
-    let a = crate::transient_0::decode_bool(reader)?;
-    let b = crate::transient_0::decode_bool(reader)?;
+pub fn decode_struct_with_bool(reader: &mut impl std::io::Read, shared_values: &mut ::std::vec::Vec::<::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>>) -> ::std::io::Result::<crate::data::StructWithBool> {
+    let a = crate::transient_0::decode_bool(reader, shared_values)?;
+    let b = crate::transient_0::decode_bool(reader, shared_values)?;
     std::io::Result::Ok(crate::data::StructWithBool { a: a, b: b })
 }
 
-pub fn encode_struct_with_int_32(value: &crate::data::StructWithInt32, writer: &mut impl std::io::Write) -> ::std::io::Result::<()> {
-    crate::transient_0::encode_int_32(&value.a, writer)?;
-    crate::transient_0::encode_int_32(&value.b, writer)?;
+pub fn encode_struct_with_int_32(value: &crate::data::StructWithInt32, writer: &mut impl std::io::Write, shared_values: &mut ::std::collections::HashMap::<::core::primitive::usize, ::core::primitive::i64>) -> ::std::io::Result::<()> {
+    crate::transient_0::encode_int_32(&value.a, writer, shared_values)?;
+    crate::transient_0::encode_int_32(&value.b, writer, shared_values)?;
     ::std::io::Result::Ok(())
 }
 
-pub fn decode_struct_with_int_32(reader: &mut impl std::io::Read) -> ::std::io::Result::<crate::data::StructWithInt32> {
-    let a = crate::transient_0::decode_int_32(reader)?;
-    let b = crate::transient_0::decode_int_32(reader)?;
+pub fn decode_struct_with_int_32(reader: &mut impl std::io::Read, shared_values: &mut ::std::vec::Vec::<::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>>) -> ::std::io::Result::<crate::data::StructWithInt32> {
+    let a = crate::transient_0::decode_int_32(reader, shared_values)?;
+    let b = crate::transient_0::decode_int_32(reader, shared_values)?;
     std::io::Result::Ok(crate::data::StructWithInt32 { a: a, b: b })
 }
 
-pub fn encode_struct_with_int_64(value: &crate::data::StructWithInt64, writer: &mut impl std::io::Write) -> ::std::io::Result::<()> {
-    crate::transient_0::encode_int_64(&value.a, writer)?;
-    crate::transient_0::encode_int_64(&value.b, writer)?;
+pub fn encode_struct_with_int_64(value: &crate::data::StructWithInt64, writer: &mut impl std::io::Write, shared_values: &mut ::std::collections::HashMap::<::core::primitive::usize, ::core::primitive::i64>) -> ::std::io::Result::<()> {
+    crate::transient_0::encode_int_64(&value.a, writer, shared_values)?;
+    crate::transient_0::encode_int_64(&value.b, writer, shared_values)?;
     ::std::io::Result::Ok(())
 }
 
-pub fn decode_struct_with_int_64(reader: &mut impl std::io::Read) -> ::std::io::Result::<crate::data::StructWithInt64> {
-    let a = crate::transient_0::decode_int_64(reader)?;
-    let b = crate::transient_0::decode_int_64(reader)?;
+pub fn decode_struct_with_int_64(reader: &mut impl std::io::Read, shared_values: &mut ::std::vec::Vec::<::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>>) -> ::std::io::Result::<crate::data::StructWithInt64> {
+    let a = crate::transient_0::decode_int_64(reader, shared_values)?;
+    let b = crate::transient_0::decode_int_64(reader, shared_values)?;
     std::io::Result::Ok(crate::data::StructWithInt64 { a: a, b: b })
 }
 
-pub fn encode_struct_with_string(value: &crate::data::StructWithString, writer: &mut impl std::io::Write) -> ::std::io::Result::<()> {
-    crate::transient_0::encode_string(&value.a, writer)?;
-    crate::transient_0::encode_string(&value.b, writer)?;
+pub fn encode_struct_with_string(value: &crate::data::StructWithString, writer: &mut impl std::io::Write, shared_values: &mut ::std::collections::HashMap::<::core::primitive::usize, ::core::primitive::i64>) -> ::std::io::Result::<()> {
+    crate::transient_0::encode_string(&value.a, writer, shared_values)?;
+    crate::transient_0::encode_string(&value.b, writer, shared_values)?;
     ::std::io::Result::Ok(())
 }
 
-pub fn decode_struct_with_string(reader: &mut impl std::io::Read) -> ::std::io::Result::<crate::data::StructWithString> {
-    let a = crate::transient_0::decode_string(reader)?;
-    let b = crate::transient_0::decode_string(reader)?;
+pub fn decode_struct_with_string(reader: &mut impl std::io::Read, shared_values: &mut ::std::vec::Vec::<::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>>) -> ::std::io::Result::<crate::data::StructWithString> {
+    let a = crate::transient_0::decode_string(reader, shared_values)?;
+    let b = crate::transient_0::decode_string(reader, shared_values)?;
     std::io::Result::Ok(crate::data::StructWithString { a: a, b: b })
 }
 
-pub fn encode_struct_with_struct(value: &crate::data::StructWithStruct, writer: &mut impl std::io::Write) -> ::std::io::Result::<()> {
-    crate::data::transient_0::encode_struct_with_int_32(&value.inner, writer)?;
-    crate::transient_0::encode_int_32(&value.c, writer)?;
+pub fn encode_struct_with_struct(value: &crate::data::StructWithStruct, writer: &mut impl std::io::Write, shared_values: &mut ::std::collections::HashMap::<::core::primitive::usize, ::core::primitive::i64>) -> ::std::io::Result::<()> {
+    crate::data::transient_0::encode_struct_with_int_32(&value.inner, writer, shared_values)?;
+    crate::transient_0::encode_int_32(&value.c, writer, shared_values)?;
     ::std::io::Result::Ok(())
 }
 
-pub fn decode_struct_with_struct(reader: &mut impl std::io::Read) -> ::std::io::Result::<crate::data::StructWithStruct> {
-    let inner = crate::data::transient_0::decode_struct_with_int_32(reader)?;
-    let c = crate::transient_0::decode_int_32(reader)?;
+pub fn decode_struct_with_struct(reader: &mut impl std::io::Read, shared_values: &mut ::std::vec::Vec::<::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>>) -> ::std::io::Result::<crate::data::StructWithStruct> {
+    let inner = crate::data::transient_0::decode_struct_with_int_32(reader, shared_values)?;
+    let c = crate::transient_0::decode_int_32(reader, shared_values)?;
     std::io::Result::Ok(crate::data::StructWithStruct { inner: inner, c: c })
 }
 
-pub fn encode_struct_with_list(value: &crate::data::StructWithList, writer: &mut impl std::io::Write) -> ::std::io::Result::<()> {
+pub fn encode_struct_with_list(value: &crate::data::StructWithList, writer: &mut impl std::io::Write, shared_values: &mut ::std::collections::HashMap::<::core::primitive::usize, ::core::primitive::i64>) -> ::std::io::Result::<()> {
     {
-        crate::transient_0::encode_int_64(&(((&value.a).len()).try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))?, writer)?;
+        crate::transient_0::encode_int_64(&(((&value.a).len()).try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))?, writer, shared_values)?;
         for element in &value.a {
-            crate::transient_0::encode_int_64(element, writer)?;
+            crate::transient_0::encode_int_64(element, writer, shared_values)?;
         };
     };
     {
-        crate::transient_0::encode_int_64(&(((&value.b).len()).try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))?, writer)?;
+        crate::transient_0::encode_int_64(&(((&value.b).len()).try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))?, writer, shared_values)?;
         for element in &value.b {
-            crate::data::transient_0::encode_struct_with_int_32(element, writer)?;
+            crate::data::transient_0::encode_struct_with_int_32(element, writer, shared_values)?;
         };
     };
     ::std::io::Result::Ok(())
 }
 
-pub fn decode_struct_with_list(reader: &mut impl std::io::Read) -> ::std::io::Result::<crate::data::StructWithList> {
+pub fn decode_struct_with_list(reader: &mut impl std::io::Read, shared_values: &mut ::std::vec::Vec::<::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>>) -> ::std::io::Result::<crate::data::StructWithList> {
     let a = {
-        let len = crate::transient_0::decode_int_64(reader)?;
+        let len = crate::transient_0::decode_int_64(reader, shared_values)?;
         let mut elements = ::std::vec::Vec::with_capacity((len.try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))?);
         for _ in 0..len {
-            elements.push(crate::transient_0::decode_int_64(reader)?);
+            elements.push(crate::transient_0::decode_int_64(reader, shared_values)?);
         };
         elements
     };
     let b = {
-        let len = crate::transient_0::decode_int_64(reader)?;
+        let len = crate::transient_0::decode_int_64(reader, shared_values)?;
         let mut elements = ::std::vec::Vec::with_capacity((len.try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))?);
         for _ in 0..len {
-            elements.push(crate::data::transient_0::decode_struct_with_int_32(reader)?);
+            elements.push(crate::data::transient_0::decode_struct_with_int_32(reader, shared_values)?);
         };
         elements
     };
     std::io::Result::Ok(crate::data::StructWithList { a: a, b: b })
 }
 
-pub fn encode_struct_with_option(value: &crate::data::StructWithOption, writer: &mut impl std::io::Write) -> ::std::io::Result::<()> {
+pub fn encode_struct_with_option(value: &crate::data::StructWithOption, writer: &mut impl std::io::Write, shared_values: &mut ::std::collections::HashMap::<::core::primitive::usize, ::core::primitive::i64>) -> ::std::io::Result::<()> {
     match &value.a {
         ::std::option::Option::Some(value) => {
-            crate::transient_0::encode_bool(&true, writer)?;
-            crate::transient_0::encode_int_64(&value, writer)?;
+            crate::transient_0::encode_bool(&true, writer, shared_values)?;
+            crate::transient_0::encode_int_64(&value, writer, shared_values)?;
         },
         ::std::option::Option::None => {
-            crate::transient_0::encode_bool(&false, writer)?;
+            crate::transient_0::encode_bool(&false, writer, shared_values)?;
         },
     };
     match &value.b {
         ::std::option::Option::Some(value) => {
-            crate::transient_0::encode_bool(&true, writer)?;
-            crate::data::transient_0::encode_struct_with_int_32(&value, writer)?;
+            crate::transient_0::encode_bool(&true, writer, shared_values)?;
+            crate::data::transient_0::encode_struct_with_int_32(&value, writer, shared_values)?;
         },
         ::std::option::Option::None => {
-            crate::transient_0::encode_bool(&false, writer)?;
+            crate::transient_0::encode_bool(&false, writer, shared_values)?;
         },
     };
     ::std::io::Result::Ok(())
 }
 
-pub fn decode_struct_with_option(reader: &mut impl std::io::Read) -> ::std::io::Result::<crate::data::StructWithOption> {
+pub fn decode_struct_with_option(reader: &mut impl std::io::Read, shared_values: &mut ::std::vec::Vec::<::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>>) -> ::std::io::Result::<crate::data::StructWithOption> {
     let a = {
-        let is_some = crate::transient_0::decode_bool(reader)?;
+        let is_some = crate::transient_0::decode_bool(reader, shared_values)?;
         if is_some {
-            ::std::option::Option::Some(crate::transient_0::decode_int_64(reader)?)
+            ::std::option::Option::Some(crate::transient_0::decode_int_64(reader, shared_values)?)
         } else {
             ::std::option::Option::None
         }
     };
     let b = {
-        let is_some = crate::transient_0::decode_bool(reader)?;
+        let is_some = crate::transient_0::decode_bool(reader, shared_values)?;
         if is_some {
-            ::std::option::Option::Some(crate::data::transient_0::decode_struct_with_int_32(reader)?)
+            ::std::option::Option::Some(crate::data::transient_0::decode_struct_with_int_32(reader, shared_values)?)
         } else {
             ::std::option::Option::None
         }
@@ -138,17 +138,17 @@ pub fn decode_struct_with_option(reader: &mut impl std::io::Read) -> ::std::io::
     std::io::Result::Ok(crate::data::StructWithOption { a: a, b: b })
 }
 
-pub fn encode_enum_with_variants(value: &crate::data::EnumWithVariants, writer: &mut impl std::io::Write) -> ::std::io::Result::<()> {
+pub fn encode_enum_with_variants(value: &crate::data::EnumWithVariants, writer: &mut impl std::io::Write, shared_values: &mut ::std::collections::HashMap::<::core::primitive::usize, ::core::primitive::i64>) -> ::std::io::Result::<()> {
     crate::transient_0::encode_int_32(&match value {
         crate::data::EnumWithVariants::Zero => 0,
         crate::data::EnumWithVariants::One => 1,
         crate::data::EnumWithVariants::Two => 2,
-    }, writer)?;
+    }, writer, shared_values)?;
     ::std::io::Result::Ok(())
 }
 
-pub fn decode_enum_with_variants(reader: &mut impl std::io::Read) -> ::std::io::Result::<crate::data::EnumWithVariants> {
-    std::io::Result::Ok(match &crate::transient_0::decode_int_32(reader)? {
+pub fn decode_enum_with_variants(reader: &mut impl std::io::Read, shared_values: &mut ::std::vec::Vec::<::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>>) -> ::std::io::Result::<crate::data::EnumWithVariants> {
+    std::io::Result::Ok(match &crate::transient_0::decode_int_32(reader, shared_values)? {
         0 => crate::data::EnumWithVariants::Zero,
         1 => crate::data::EnumWithVariants::One,
         2 => crate::data::EnumWithVariants::Two,
@@ -156,116 +156,248 @@ pub fn decode_enum_with_variants(reader: &mut impl std::io::Read) -> ::std::io::
     })
 }
 
-pub fn encode_struct_with_enum(value: &crate::data::StructWithEnum, writer: &mut impl std::io::Write) -> ::std::io::Result::<()> {
-    crate::data::transient_0::encode_enum_with_variants(&value.inner, writer)?;
-    crate::transient_0::encode_int_32(&value.c, writer)?;
+pub fn encode_struct_with_enum(value: &crate::data::StructWithEnum, writer: &mut impl std::io::Write, shared_values: &mut ::std::collections::HashMap::<::core::primitive::usize, ::core::primitive::i64>) -> ::std::io::Result::<()> {
+    crate::data::transient_0::encode_enum_with_variants(&value.inner, writer, shared_values)?;
+    crate::transient_0::encode_int_32(&value.c, writer, shared_values)?;
     ::std::io::Result::Ok(())
 }
 
-pub fn decode_struct_with_enum(reader: &mut impl std::io::Read) -> ::std::io::Result::<crate::data::StructWithEnum> {
-    let inner = crate::data::transient_0::decode_enum_with_variants(reader)?;
-    let c = crate::transient_0::decode_int_32(reader)?;
+pub fn decode_struct_with_enum(reader: &mut impl std::io::Read, shared_values: &mut ::std::vec::Vec::<::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>>) -> ::std::io::Result::<crate::data::StructWithEnum> {
+    let inner = crate::data::transient_0::decode_enum_with_variants(reader, shared_values)?;
+    let c = crate::transient_0::decode_int_32(reader, shared_values)?;
     std::io::Result::Ok(crate::data::StructWithEnum { inner: inner, c: c })
 }
 
-pub fn encode_sum_with_variants(value: &crate::data::SumWithVariants, writer: &mut impl std::io::Write) -> ::std::io::Result::<()> {
+pub fn encode_sum_with_variants(value: &crate::data::SumWithVariants, writer: &mut impl std::io::Write, shared_values: &mut ::std::collections::HashMap::<::core::primitive::usize, ::core::primitive::i64>) -> ::std::io::Result::<()> {
     match value {
         crate::data::SumWithVariants::VariantOne(value) => {
-            crate::transient_0::encode_int_32(&0, writer)?;
-            crate::data::transient_0::encode_variant_one(value, writer)?;
+            crate::transient_0::encode_int_32(&0, writer, shared_values)?;
+            crate::data::transient_0::encode_variant_one(value, writer, shared_values)?;
         },
         crate::data::SumWithVariants::VariantTwo(value) => {
-            crate::transient_0::encode_int_32(&1, writer)?;
-            crate::data::transient_0::encode_variant_two(value, writer)?;
+            crate::transient_0::encode_int_32(&1, writer, shared_values)?;
+            crate::data::transient_0::encode_variant_two(value, writer, shared_values)?;
         },
     };
     ::std::io::Result::Ok(())
 }
 
-pub fn decode_sum_with_variants(reader: &mut impl std::io::Read) -> ::std::io::Result::<crate::data::SumWithVariants> {
-    std::io::Result::Ok(match &crate::transient_0::decode_int_32(reader)? {
-        0 => crate::data::SumWithVariants::VariantOne(crate::data::transient_0::decode_variant_one(reader)?),
-        1 => crate::data::SumWithVariants::VariantTwo(crate::data::transient_0::decode_variant_two(reader)?),
+pub fn decode_sum_with_variants(reader: &mut impl std::io::Read, shared_values: &mut ::std::vec::Vec::<::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>>) -> ::std::io::Result::<crate::data::SumWithVariants> {
+    std::io::Result::Ok(match &crate::transient_0::decode_int_32(reader, shared_values)? {
+        0 => crate::data::SumWithVariants::VariantOne(crate::data::transient_0::decode_variant_one(reader, shared_values)?),
+        1 => crate::data::SumWithVariants::VariantTwo(crate::data::transient_0::decode_variant_two(reader, shared_values)?),
         _ => todo!(),
     })
 }
 
-pub fn encode_variant_one(value: &crate::data::VariantOne, writer: &mut impl std::io::Write) -> ::std::io::Result::<()> {
-    crate::transient_0::encode_int_32(&value.a, writer)?;
+pub fn encode_variant_one(value: &crate::data::VariantOne, writer: &mut impl std::io::Write, shared_values: &mut ::std::collections::HashMap::<::core::primitive::usize, ::core::primitive::i64>) -> ::std::io::Result::<()> {
+    crate::transient_0::encode_int_32(&value.a, writer, shared_values)?;
     ::std::io::Result::Ok(())
 }
 
-pub fn decode_variant_one(reader: &mut impl std::io::Read) -> ::std::io::Result::<crate::data::VariantOne> {
-    let a = crate::transient_0::decode_int_32(reader)?;
+pub fn decode_variant_one(reader: &mut impl std::io::Read, shared_values: &mut ::std::vec::Vec::<::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>>) -> ::std::io::Result::<crate::data::VariantOne> {
+    let a = crate::transient_0::decode_int_32(reader, shared_values)?;
     std::io::Result::Ok(crate::data::VariantOne { a: a })
 }
 
-pub fn encode_variant_two(value: &crate::data::VariantTwo, writer: &mut impl std::io::Write) -> ::std::io::Result::<()> {
-    crate::transient_0::encode_int_64(&value.a, writer)?;
+pub fn encode_variant_two(value: &crate::data::VariantTwo, writer: &mut impl std::io::Write, shared_values: &mut ::std::collections::HashMap::<::core::primitive::usize, ::core::primitive::i64>) -> ::std::io::Result::<()> {
+    crate::transient_0::encode_int_64(&value.a, writer, shared_values)?;
     ::std::io::Result::Ok(())
 }
 
-pub fn decode_variant_two(reader: &mut impl std::io::Read) -> ::std::io::Result::<crate::data::VariantTwo> {
-    let a = crate::transient_0::decode_int_64(reader)?;
+pub fn decode_variant_two(reader: &mut impl std::io::Read, shared_values: &mut ::std::vec::Vec::<::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>>) -> ::std::io::Result::<crate::data::VariantTwo> {
+    let a = crate::transient_0::decode_int_64(reader, shared_values)?;
     std::io::Result::Ok(crate::data::VariantTwo { a: a })
 }
 
-pub fn encode_struct_with_sum(value: &crate::data::StructWithSum, writer: &mut impl std::io::Write) -> ::std::io::Result::<()> {
-    crate::data::transient_0::encode_sum_with_variants(&value.inner, writer)?;
-    crate::transient_0::encode_int_32(&value.b, writer)?;
+pub fn encode_struct_with_sum(value: &crate::data::StructWithSum, writer: &mut impl std::io::Write, shared_values: &mut ::std::collections::HashMap::<::core::primitive::usize, ::core::primitive::i64>) -> ::std::io::Result::<()> {
+    crate::data::transient_0::encode_sum_with_variants(&value.inner, writer, shared_values)?;
+    crate::transient_0::encode_int_32(&value.b, writer, shared_values)?;
     ::std::io::Result::Ok(())
 }
 
-pub fn decode_struct_with_sum(reader: &mut impl std::io::Read) -> ::std::io::Result::<crate::data::StructWithSum> {
-    let inner = crate::data::transient_0::decode_sum_with_variants(reader)?;
-    let b = crate::transient_0::decode_int_32(reader)?;
+pub fn decode_struct_with_sum(reader: &mut impl std::io::Read, shared_values: &mut ::std::vec::Vec::<::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>>) -> ::std::io::Result::<crate::data::StructWithSum> {
+    let inner = crate::data::transient_0::decode_sum_with_variants(reader, shared_values)?;
+    let b = crate::transient_0::decode_int_32(reader, shared_values)?;
     std::io::Result::Ok(crate::data::StructWithSum { inner: inner, b: b })
 }
 
-pub fn encode_struct_with_list_of_shared(value: &crate::data::StructWithListOfShared, writer: &mut impl std::io::Write) -> ::std::io::Result::<()> {
+pub fn encode_struct_with_list_of_shared(value: &crate::data::StructWithListOfShared, writer: &mut impl std::io::Write, shared_values: &mut ::std::collections::HashMap::<::core::primitive::usize, ::core::primitive::i64>) -> ::std::io::Result::<()> {
     {
-        crate::transient_0::encode_int_64(&(((&value.inner).len()).try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))?, writer)?;
+        crate::transient_0::encode_int_64(&(((&value.inner).len()).try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))?, writer, shared_values)?;
         for element in &value.inner {
-            crate::data::transient_0::encode_struct_with_int_32(element.as_ref(), writer)?;
+            {
+                let ptr = ::std::sync::Arc::as_ptr(&element) as ::core::primitive::usize;
+                match (shared_values.get(&ptr)).copied() {
+                    ::std::option::Option::Some(id) => {
+                        crate::transient_0::encode_int_64(&id, writer, shared_values)?;
+                    },
+                    ::std::option::Option::None => {
+                        let id = ((shared_values.len()).try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))?;
+                        crate::transient_0::encode_int_64(&id, writer, shared_values)?;
+                        shared_values.insert(ptr, id);
+                        crate::data::transient_0::encode_struct_with_int_32(element.as_ref(), writer, shared_values)?;
+                    },
+                };
+            };
         };
     };
     ::std::io::Result::Ok(())
 }
 
-pub fn decode_struct_with_list_of_shared(reader: &mut impl std::io::Read) -> ::std::io::Result::<crate::data::StructWithListOfShared> {
+pub fn decode_struct_with_list_of_shared(reader: &mut impl std::io::Read, shared_values: &mut ::std::vec::Vec::<::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>>) -> ::std::io::Result::<crate::data::StructWithListOfShared> {
     let inner = {
-        let len = crate::transient_0::decode_int_64(reader)?;
+        let len = crate::transient_0::decode_int_64(reader, shared_values)?;
         let mut elements = ::std::vec::Vec::with_capacity((len.try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))?);
         for _ in 0..len {
-            elements.push(::std::sync::Arc::new(crate::data::transient_0::decode_struct_with_int_32(reader)?));
+            elements.push({
+                let id = crate::transient_0::decode_int_64(reader, shared_values)?;
+                if id < ((shared_values.len()).try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))? {
+                    ((::std::sync::Arc::clone(&shared_values[id as ::core::primitive::usize])).downcast()).unwrap()
+                } else {
+                    let decoded_value = ::std::sync::Arc::new(crate::data::transient_0::decode_struct_with_int_32(reader, shared_values)?);
+                    shared_values.push(::std::sync::Arc::clone(&decoded_value) as ::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>);
+                    decoded_value
+                }
+            });
         };
         elements
     };
     std::io::Result::Ok(crate::data::StructWithListOfShared { inner: inner })
 }
 
-pub fn encode_struct_with_different_shared_types(value: &crate::data::StructWithDifferentSharedTypes, writer: &mut impl std::io::Write) -> ::std::io::Result::<()> {
-    crate::data::transient_0::encode_struct_with_int_32((&value.a).as_ref(), writer)?;
-    crate::data::transient_0::encode_struct_with_int_64((&value.b).as_ref(), writer)?;
-    crate::data::transient_0::encode_struct_with_int_32((&value.c).as_ref(), writer)?;
+pub fn encode_struct_with_different_shared_types(value: &crate::data::StructWithDifferentSharedTypes, writer: &mut impl std::io::Write, shared_values: &mut ::std::collections::HashMap::<::core::primitive::usize, ::core::primitive::i64>) -> ::std::io::Result::<()> {
+    {
+        let ptr = ::std::sync::Arc::as_ptr(&&value.a) as ::core::primitive::usize;
+        match (shared_values.get(&ptr)).copied() {
+            ::std::option::Option::Some(id) => {
+                crate::transient_0::encode_int_64(&id, writer, shared_values)?;
+            },
+            ::std::option::Option::None => {
+                let id = ((shared_values.len()).try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))?;
+                crate::transient_0::encode_int_64(&id, writer, shared_values)?;
+                shared_values.insert(ptr, id);
+                crate::data::transient_0::encode_struct_with_int_32((&value.a).as_ref(), writer, shared_values)?;
+            },
+        };
+    };
+    {
+        let ptr = ::std::sync::Arc::as_ptr(&&value.b) as ::core::primitive::usize;
+        match (shared_values.get(&ptr)).copied() {
+            ::std::option::Option::Some(id) => {
+                crate::transient_0::encode_int_64(&id, writer, shared_values)?;
+            },
+            ::std::option::Option::None => {
+                let id = ((shared_values.len()).try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))?;
+                crate::transient_0::encode_int_64(&id, writer, shared_values)?;
+                shared_values.insert(ptr, id);
+                crate::data::transient_0::encode_struct_with_int_64((&value.b).as_ref(), writer, shared_values)?;
+            },
+        };
+    };
+    {
+        let ptr = ::std::sync::Arc::as_ptr(&&value.c) as ::core::primitive::usize;
+        match (shared_values.get(&ptr)).copied() {
+            ::std::option::Option::Some(id) => {
+                crate::transient_0::encode_int_64(&id, writer, shared_values)?;
+            },
+            ::std::option::Option::None => {
+                let id = ((shared_values.len()).try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))?;
+                crate::transient_0::encode_int_64(&id, writer, shared_values)?;
+                shared_values.insert(ptr, id);
+                crate::data::transient_0::encode_struct_with_int_32((&value.c).as_ref(), writer, shared_values)?;
+            },
+        };
+    };
     ::std::io::Result::Ok(())
 }
 
-pub fn decode_struct_with_different_shared_types(reader: &mut impl std::io::Read) -> ::std::io::Result::<crate::data::StructWithDifferentSharedTypes> {
-    let a = ::std::sync::Arc::new(crate::data::transient_0::decode_struct_with_int_32(reader)?);
-    let b = ::std::sync::Arc::new(crate::data::transient_0::decode_struct_with_int_64(reader)?);
-    let c = ::std::sync::Arc::new(crate::data::transient_0::decode_struct_with_int_32(reader)?);
+pub fn decode_struct_with_different_shared_types(reader: &mut impl std::io::Read, shared_values: &mut ::std::vec::Vec::<::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>>) -> ::std::io::Result::<crate::data::StructWithDifferentSharedTypes> {
+    let a = {
+        let id = crate::transient_0::decode_int_64(reader, shared_values)?;
+        if id < ((shared_values.len()).try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))? {
+            ((::std::sync::Arc::clone(&shared_values[id as ::core::primitive::usize])).downcast()).unwrap()
+        } else {
+            let decoded_value = ::std::sync::Arc::new(crate::data::transient_0::decode_struct_with_int_32(reader, shared_values)?);
+            shared_values.push(::std::sync::Arc::clone(&decoded_value) as ::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>);
+            decoded_value
+        }
+    };
+    let b = {
+        let id = crate::transient_0::decode_int_64(reader, shared_values)?;
+        if id < ((shared_values.len()).try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))? {
+            ((::std::sync::Arc::clone(&shared_values[id as ::core::primitive::usize])).downcast()).unwrap()
+        } else {
+            let decoded_value = ::std::sync::Arc::new(crate::data::transient_0::decode_struct_with_int_64(reader, shared_values)?);
+            shared_values.push(::std::sync::Arc::clone(&decoded_value) as ::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>);
+            decoded_value
+        }
+    };
+    let c = {
+        let id = crate::transient_0::decode_int_64(reader, shared_values)?;
+        if id < ((shared_values.len()).try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))? {
+            ((::std::sync::Arc::clone(&shared_values[id as ::core::primitive::usize])).downcast()).unwrap()
+        } else {
+            let decoded_value = ::std::sync::Arc::new(crate::data::transient_0::decode_struct_with_int_32(reader, shared_values)?);
+            shared_values.push(::std::sync::Arc::clone(&decoded_value) as ::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>);
+            decoded_value
+        }
+    };
     std::io::Result::Ok(crate::data::StructWithDifferentSharedTypes { a: a, b: b, c: c })
 }
 
-pub fn encode_struct_with_shared_sum_and_variant(value: &crate::data::StructWithSharedSumAndVariant, writer: &mut impl std::io::Write) -> ::std::io::Result::<()> {
-    crate::data::transient_0::encode_sum_with_variants((&value.a).as_ref(), writer)?;
-    crate::data::transient_0::encode_variant_one((&value.b).as_ref(), writer)?;
+pub fn encode_struct_with_shared_sum_and_variant(value: &crate::data::StructWithSharedSumAndVariant, writer: &mut impl std::io::Write, shared_values: &mut ::std::collections::HashMap::<::core::primitive::usize, ::core::primitive::i64>) -> ::std::io::Result::<()> {
+    {
+        let ptr = ::std::sync::Arc::as_ptr(&&value.a) as ::core::primitive::usize;
+        match (shared_values.get(&ptr)).copied() {
+            ::std::option::Option::Some(id) => {
+                crate::transient_0::encode_int_64(&id, writer, shared_values)?;
+            },
+            ::std::option::Option::None => {
+                let id = ((shared_values.len()).try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))?;
+                crate::transient_0::encode_int_64(&id, writer, shared_values)?;
+                shared_values.insert(ptr, id);
+                crate::data::transient_0::encode_sum_with_variants((&value.a).as_ref(), writer, shared_values)?;
+            },
+        };
+    };
+    {
+        let ptr = ::std::sync::Arc::as_ptr(&&value.b) as ::core::primitive::usize;
+        match (shared_values.get(&ptr)).copied() {
+            ::std::option::Option::Some(id) => {
+                crate::transient_0::encode_int_64(&id, writer, shared_values)?;
+            },
+            ::std::option::Option::None => {
+                let id = ((shared_values.len()).try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))?;
+                crate::transient_0::encode_int_64(&id, writer, shared_values)?;
+                shared_values.insert(ptr, id);
+                crate::data::transient_0::encode_variant_one((&value.b).as_ref(), writer, shared_values)?;
+            },
+        };
+    };
     ::std::io::Result::Ok(())
 }
 
-pub fn decode_struct_with_shared_sum_and_variant(reader: &mut impl std::io::Read) -> ::std::io::Result::<crate::data::StructWithSharedSumAndVariant> {
-    let a = ::std::sync::Arc::new(crate::data::transient_0::decode_sum_with_variants(reader)?);
-    let b = ::std::sync::Arc::new(crate::data::transient_0::decode_variant_one(reader)?);
+pub fn decode_struct_with_shared_sum_and_variant(reader: &mut impl std::io::Read, shared_values: &mut ::std::vec::Vec::<::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>>) -> ::std::io::Result::<crate::data::StructWithSharedSumAndVariant> {
+    let a = {
+        let id = crate::transient_0::decode_int_64(reader, shared_values)?;
+        if id < ((shared_values.len()).try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))? {
+            ((::std::sync::Arc::clone(&shared_values[id as ::core::primitive::usize])).downcast()).unwrap()
+        } else {
+            let decoded_value = ::std::sync::Arc::new(crate::data::transient_0::decode_sum_with_variants(reader, shared_values)?);
+            shared_values.push(::std::sync::Arc::clone(&decoded_value) as ::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>);
+            decoded_value
+        }
+    };
+    let b = {
+        let id = crate::transient_0::decode_int_64(reader, shared_values)?;
+        if id < ((shared_values.len()).try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))? {
+            ((::std::sync::Arc::clone(&shared_values[id as ::core::primitive::usize])).downcast()).unwrap()
+        } else {
+            let decoded_value = ::std::sync::Arc::new(crate::data::transient_0::decode_variant_one(reader, shared_values)?);
+            shared_values.push(::std::sync::Arc::clone(&decoded_value) as ::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>);
+            decoded_value
+        }
+    };
     std::io::Result::Ok(crate::data::StructWithSharedSumAndVariant { a: a, b: b })
 }
diff --git a/examples/11-transient-0/output/rust/src/gen/transient_0.rs b/examples/11-transient-0/output/rust/src/gen/transient_0.rs
index 560fe51..393b397 100644
--- a/examples/11-transient-0/output/rust/src/gen/transient_0.rs
+++ b/examples/11-transient-0/output/rust/src/gen/transient_0.rs
@@ -1,6 +1,6 @@
 // Generated by hobgoblin.
 
-pub fn encode_bool(value: &::core::primitive::bool, writer: &mut impl std::io::Write) -> ::std::io::Result::<()> {
+pub fn encode_bool(value: &::core::primitive::bool, writer: &mut impl std::io::Write, shared_values: &mut ::std::collections::HashMap::<::core::primitive::usize, ::core::primitive::i64>) -> ::std::io::Result::<()> {
     if *value {
         writer.write_all(&1u8.to_le_bytes())?;
     } else {
@@ -9,7 +9,7 @@ pub fn encode_bool(value: &::core::primitive::bool, writer: &mut impl std::io::W
     ::std::io::Result::Ok(())
 }
 
-pub fn decode_bool(reader: &mut impl std::io::Read) -> ::std::io::Result::<::core::primitive::bool> {
+pub fn decode_bool(reader: &mut impl std::io::Read, shared_values: &mut ::std::vec::Vec::<::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>>) -> ::std::io::Result::<::core::primitive::bool> {
     let int_value = {
         let bytes = {
             let mut bytes = [0; 1];
@@ -25,12 +25,12 @@ pub fn decode_bool(reader: &mut impl std::io::Read) -> ::std::io::Result::<::cor
     })
 }
 
-pub fn encode_int_32(value: &::core::primitive::i32, writer: &mut impl std::io::Write) -> ::std::io::Result::<()> {
+pub fn encode_int_32(value: &::core::primitive::i32, writer: &mut impl std::io::Write, shared_values: &mut ::std::collections::HashMap::<::core::primitive::usize, ::core::primitive::i64>) -> ::std::io::Result::<()> {
     writer.write_all(&value.to_le_bytes())?;
     ::std::io::Result::Ok(())
 }
 
-pub fn decode_int_32(reader: &mut impl std::io::Read) -> ::std::io::Result::<::core::primitive::i32> {
+pub fn decode_int_32(reader: &mut impl std::io::Read, shared_values: &mut ::std::vec::Vec::<::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>>) -> ::std::io::Result::<::core::primitive::i32> {
     let bytes = {
         let mut bytes = [0; 4];
         reader.read_exact(&mut bytes)?;
@@ -39,12 +39,12 @@ pub fn decode_int_32(reader: &mut impl std::io::Read) -> ::std::io::Result::<::c
     std::io::Result::Ok(::core::primitive::i32::from_le_bytes(bytes))
 }
 
-pub fn encode_int_64(value: &::core::primitive::i64, writer: &mut impl std::io::Write) -> ::std::io::Result::<()> {
+pub fn encode_int_64(value: &::core::primitive::i64, writer: &mut impl std::io::Write, shared_values: &mut ::std::collections::HashMap::<::core::primitive::usize, ::core::primitive::i64>) -> ::std::io::Result::<()> {
     writer.write_all(&value.to_le_bytes())?;
     ::std::io::Result::Ok(())
 }
 
-pub fn decode_int_64(reader: &mut impl std::io::Read) -> ::std::io::Result::<::core::primitive::i64> {
+pub fn decode_int_64(reader: &mut impl std::io::Read, shared_values: &mut ::std::vec::Vec::<::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>>) -> ::std::io::Result::<::core::primitive::i64> {
     let bytes = {
         let mut bytes = [0; 8];
         reader.read_exact(&mut bytes)?;
@@ -53,14 +53,14 @@ pub fn decode_int_64(reader: &mut impl std::io::Read) -> ::std::io::Result::<::c
     std::io::Result::Ok(::core::primitive::i64::from_le_bytes(bytes))
 }
 
-pub fn encode_string(value: &::std::string::String, writer: &mut impl std::io::Write) -> ::std::io::Result::<()> {
-    crate::transient_0::encode_int_64(&((value.len()).try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))?, writer)?;
+pub fn encode_string(value: &::std::string::String, writer: &mut impl std::io::Write, shared_values: &mut ::std::collections::HashMap::<::core::primitive::usize, ::core::primitive::i64>) -> ::std::io::Result::<()> {
+    crate::transient_0::encode_int_64(&((value.len()).try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))?, writer, shared_values)?;
     writer.write_all(value.as_bytes())?;
     ::std::io::Result::Ok(())
 }
 
-pub fn decode_string(reader: &mut impl std::io::Read) -> ::std::io::Result::<::std::string::String> {
-    let len = crate::transient_0::decode_int_64(reader)?;
+pub fn decode_string(reader: &mut impl std::io::Read, shared_values: &mut ::std::vec::Vec::<::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>>) -> ::std::io::Result::<::std::string::String> {
+    let len = crate::transient_0::decode_int_64(reader, shared_values)?;
     let bytes = {
         let mut bytes = vec![0u8; (len.try_into()).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))?];
         reader.read_exact(&mut bytes)?;
diff --git a/examples/11-transient-0/output/rust/src/lib.rs b/examples/11-transient-0/output/rust/src/lib.rs
index 63e7c67..63a2799 100644
--- a/examples/11-transient-0/output/rust/src/lib.rs
+++ b/examples/11-transient-0/output/rust/src/lib.rs
@@ -3,8 +3,10 @@ pub mod transient_0;
 
 #[cfg(test)]
 mod test {
+    use std::any::Any;
     use std::io::Cursor;
     use std::sync::Arc;
+    use std::collections::HashMap;
     use super::data::{EnumWithVariants, StructWithBool, StructWithDifferentSharedTypes, StructWithEnum, StructWithInt32, StructWithInt64, StructWithList, StructWithListOfShared, StructWithOption, StructWithSharedSumAndVariant, StructWithString, StructWithStruct, StructWithSum, SumWithVariants, VariantOne, VariantTwo };
 
     #[test]
@@ -171,17 +173,21 @@ mod test {
 
     #[test]
     fn struct_with_list_of_shared() {
+        let a = Arc::new(StructWithInt32 { a: 10, b: 25 });
+        let b = Arc::new(StructWithInt32 { a: 42, b: 47 });
+
         let value = StructWithListOfShared {
-            inner: vec![
-                Arc::new(StructWithInt32 { a: 10, b: 25 }),
-            ],
+            inner: vec![Arc::clone(&a), Arc::clone(&a), Arc::clone(&b), a, b],
         };
 
-        assert_round_trip_encoding(
+        let decoded_value = assert_round_trip_encoding(
             value,
             super::data::transient_0::encode_struct_with_list_of_shared,
             super::data::transient_0::decode_struct_with_list_of_shared,
         );
+        assert!(Arc::ptr_eq(&decoded_value.inner[0], &decoded_value.inner[1]));
+        assert!(Arc::ptr_eq(&decoded_value.inner[0], &decoded_value.inner[3]));
+        assert!(Arc::ptr_eq(&decoded_value.inner[2], &decoded_value.inner[4]));
     }
 
     #[test]
@@ -215,15 +221,17 @@ mod test {
 
     fn assert_round_trip_encoding<T: std::cmp::PartialEq + std::fmt::Debug>(
         value: T,
-        encode: impl Fn(&T, &mut Cursor<Vec<u8>>) -> std::io::Result<()>,
-        decode: impl Fn(&mut Cursor<Vec<u8>>) -> std::io::Result<T>,
-    ) {
+        encode: impl Fn(&T, &mut Cursor<Vec<u8>>, &mut HashMap<usize, i64>) -> std::io::Result<()>,
+        decode: impl Fn(&mut Cursor<Vec<u8>>, &mut Vec<Arc<dyn Any + Sync + Send>>) -> std::io::Result<T>,
+    ) -> T {
         let mut bytes = Cursor::new(Vec::new());
-        encode(&value, &mut bytes).unwrap();
+        encode(&value, &mut bytes, &mut HashMap::new()).unwrap();
 
         bytes.set_position(0);
-        let decoded_value = decode(&mut bytes).unwrap();
+        let decoded_value = decode(&mut bytes, &mut Vec::new()).unwrap();
 
         assert_eq!(value, decoded_value);
+
+        decoded_value
     }
 }
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/rusttransient0/RustTransient0Generator.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/rusttransient0/RustTransient0Generator.java
index af28e96..e37a974 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/rusttransient0/RustTransient0Generator.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/rusttransient0/RustTransient0Generator.java
@@ -29,6 +29,7 @@ public class RustTransient0Generator implements Generator {
     private static final RustIdentifier VALUE_NAME = RustIdentifier.of("value");
     private static final RustIdentifier READER_NAME = RustIdentifier.of("reader");
     private static final RustIdentifier WRITER_NAME = RustIdentifier.of("writer");
+    private static final RustIdentifier SHARED_VALUES_NAME = RustIdentifier.of("shared_values");
 
     public static OutputConfig parseGeneratorConfig(
         Path projectRoot,
@@ -508,7 +509,13 @@ public class RustTransient0Generator implements Generator {
             encodeMethodName(type),
             List.of(
                 new RustFunctionParam(VALUE_NAME, new RustSharedReferenceType(rustType)),
-                new RustFunctionParam(WRITER_NAME, new RustMutableReferenceType(new RustImplTraitType(RustPath.of("std", "io", "Write"))))
+                new RustFunctionParam(WRITER_NAME, new RustMutableReferenceType(new RustImplTraitType(RustPath.of("std", "io", "Write")))),
+                new RustFunctionParam(
+                    SHARED_VALUES_NAME,
+                    new RustMutableReferenceType(
+                        RustTypes.hashMap(RustTypes.USIZE, RustPath.primitive("i64"))
+                    )
+                )
             ),
             Optional.of(
                 RustPath.global("std", "io", "Result")
@@ -536,7 +543,10 @@ public class RustTransient0Generator implements Generator {
             Optional.of(RustVisibility.PUB),
             decodeMethodName(type),
             List.of(
-                new RustFunctionParam(READER_NAME, new RustMutableReferenceType(new RustImplTraitType(RustPath.of("std", "io", "Read"))))
+                new RustFunctionParam(READER_NAME, new RustMutableReferenceType(new RustImplTraitType(RustPath.of("std", "io", "Read")))),
+                new RustFunctionParam(SHARED_VALUES_NAME, new RustMutableReferenceType(
+                    RustTypes.vec(RustTypes.arc(RustTypes.dyn(RustTypes.ANY, RustTypes.SYNC, RustTypes.SEND)))
+                ))
             ),
             Optional.of(RustPath.global("std", "io", "Result").withArgs(List.of(rustType))),
             Optional.of(new RustBlockExpression(
@@ -637,7 +647,7 @@ public class RustTransient0Generator implements Generator {
 
         return new RustExpressionStatement(new RustTryPropagationExpression(new RustCallExpression(
             rustEncodeFunctionPath,
-            List.of(value, RustPath.of(WRITER_NAME))
+            List.of(value, RustPath.of(WRITER_NAME), RustPath.of(SHARED_VALUES_NAME))
         )));
     }
 
@@ -652,7 +662,7 @@ public class RustTransient0Generator implements Generator {
 
         return new RustTryPropagationExpression(new RustCallExpression(
             rustDecodeFunctionPath,
-            List.of(RustPath.of(READER_NAME))
+            List.of(RustPath.of(READER_NAME), RustPath.of(SHARED_VALUES_NAME))
         ));
     }
 
@@ -784,20 +794,161 @@ public class RustTransient0Generator implements Generator {
     }
 
     private RustStatement generateEncodeShared(RustExpression value, Type type) {
-        return generateEncode(
-            new RustCallExpression(
-                new RustFieldExpression(value, RustIdentifier.of("as_ref")),
-                List.of()
+        var ptr = RustIdentifier.of("ptr");
+        var id = RustIdentifier.of("id");
+
+        return new RustExpressionStatement(new RustBlockExpression(
+            List.of(
+                new RustLetStatement(
+                    ptr,
+                    false,
+                    new RustTypeCastExpression(
+                        new RustCallExpression(
+                            RustTypes.ARC.addSegment(RustPathSegment.of("as_ptr")),
+                            List.of(new RustPrefixExpression(RustPrefixOperator.BORROW, value))
+                        ),
+                        RustTypes.USIZE
+                    )
+                ),
+                new RustExpressionStatement(new RustMatchExpression(
+                    methodCall(
+                        methodCall(
+                            RustPath.of(SHARED_VALUES_NAME),
+                            RustIdentifier.of("get"),
+                            List.of(new RustPrefixExpression(RustPrefixOperator.BORROW, RustPath.of(ptr)))
+                        ),
+                        RustIdentifier.of("copied"),
+                        List.of()
+                    ),
+                    List.of(
+                        new RustMatchArm(
+                            new RustTupleStructPattern(RustTypes.SOME, List.of(new RustIdentifierPattern(id))),
+                            new RustBlockExpression(
+                                List.of(
+                                    generateEncode(
+                                        new RustPrefixExpression(RustPrefixOperator.BORROW, RustPath.of(id)),
+                                        NativeTypes.INT_64
+                                    )
+                                ),
+                                Optional.empty()
+                            )
+                        ),
+                        new RustMatchArm(
+                            new RustPathPattern(RustTypes.NONE),
+                            new RustBlockExpression(
+                                List.of(
+                                    new RustLetStatement(
+                                        id,
+                                        false,
+                                        tryIntoOrInvalidData(
+                                            methodCall(RustPath.of(SHARED_VALUES_NAME), RustIdentifier.of("len"), List.of())
+                                        )
+                                    ),
+                                    generateEncode(
+                                        new RustPrefixExpression(RustPrefixOperator.BORROW, RustPath.of(id)),
+                                        NativeTypes.INT_64
+                                    ),
+                                    new RustExpressionStatement(
+                                        methodCall(
+                                            RustPath.of(SHARED_VALUES_NAME),
+                                            RustIdentifier.of("insert"),
+                                            List.of(RustPath.of(ptr), RustPath.of(id))
+                                        )
+                                    ),
+                                    generateEncode(
+                                        new RustCallExpression(
+                                            new RustFieldExpression(value, RustIdentifier.of("as_ref")),
+                                            List.of()
+                                        ),
+                                        type
+                                    )
+                                ),
+                                Optional.empty()
+                            )
+                        )
+                    )
+                ))
             ),
-            type
-        );
+            Optional.empty()
+        ));
     }
 
     private RustExpression generateDecodeShared(Type type) {
-        var value = generateDecode(type);
-        return new RustCallExpression(
-            RustPath.global("std", "sync", "Arc", "new"),
-            List.of(value)
+        var id = RustIdentifier.of("id");
+        var decodedValue = RustIdentifier.of("decoded_value");
+
+        return new RustBlockExpression(
+            List.of(
+                new RustLetStatement(
+                    id,
+                    false,
+                    generateDecode(NativeTypes.INT_64)
+                )
+            ),
+            Optional.of(new RustIfExpression(
+                new RustBinaryExpression(
+                    RustBinaryOperator.LESS_THAN,
+                    RustPath.of(id),
+                    tryIntoOrInvalidData(methodCall(
+                        RustPath.of(SHARED_VALUES_NAME),
+                        RustIdentifier.of("len"),
+                        List.of()
+                    ))
+                ),
+                new RustBlockExpression(
+                    List.of(),
+                    Optional.of(
+                        methodCall(
+                            methodCall(
+                                new RustCallExpression(
+                                    RustTypes.ARC.addSegment(RustPathSegment.of("clone")),
+                                    List.of(
+                                        new RustPrefixExpression(RustPrefixOperator.BORROW, new RustIndexExpression(
+                                            RustPath.of(SHARED_VALUES_NAME),
+                                            // TODO: use try_into()
+                                            new RustTypeCastExpression(RustPath.of(id), RustTypes.USIZE)
+                                        ))
+                                    )
+                                ),
+                                RustIdentifier.of("downcast"),
+                                List.of()
+                            ),
+                            // TODO: remove unwrap
+                            RustIdentifier.of("unwrap"),
+                            List.of()
+                        )
+                    )
+                ),
+                new RustBlockExpression(
+                    List.of(
+                        new RustLetStatement(
+                            decodedValue,
+                            false,
+                            new RustCallExpression(
+                                RustTypes.ARC.addSegment(RustPathSegment.of("new")),
+                                List.of(generateDecode(type))
+                            )
+                        ),
+                        new RustExpressionStatement(methodCall(
+                            RustPath.of(SHARED_VALUES_NAME),
+                            RustIdentifier.of("push"),
+                            List.of(
+                                new RustTypeCastExpression(
+                                    new RustCallExpression(
+                                        RustTypes.ARC.addSegment(RustPathSegment.of("clone")),
+                                        List.of(new RustPrefixExpression(
+                                            RustPrefixOperator.BORROW,
+                                            RustPath.of(decodedValue)
+                                        ))
+                                    ),
+                                    RustTypes.arc(RustTypes.dyn(RustTypes.ANY, RustTypes.SYNC, RustTypes.SEND))
+                                )
+                            )
+                        ))
+                    ),
+                    Optional.of(RustPath.of(decodedValue))
+                )
+            ))
         );
     }
 
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustTypes.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustTypes.java
index c3d1cf0..1e43a24 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustTypes.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustTypes.java
@@ -1,20 +1,52 @@
 package org.zwobble.hobgoblin.compiler.output.lang.rust;
 
 import org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPath;
+import org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTraitObjectType;
 import org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustType;
 
+import java.util.Arrays;
 import java.util.List;
 
 public class RustTypes {
     private RustTypes() {}
 
+    public static RustType dyn(RustPath... bounds) {
+        return new RustTraitObjectType(Arrays.asList(bounds));
+    }
+
     public static RustPath BOOL = RustPath.primitive("bool");
     public static RustPath I32 = RustPath.primitive("i32");
     public static RustPath I64 = RustPath.primitive("i64");
-    public static RustPath STRING = RustPath.global("std", "string", "String");
+    public static RustPath USIZE = RustPath.primitive("usize");
+
+    public static RustPath ANY = RustPath.global("std", "any", "Any");
 
     public static RustPath box(RustType elementType) {
         return RustPath.global("std", "boxed", "Box")
             .withArgs(List.of(elementType));
     }
+
+    public static RustPath hashMap(RustType keyType, RustType valueType) {
+        return RustPath.global("std", "collections", "HashMap")
+            .withArgs(List.of(keyType, valueType));
+    }
+
+    public static RustPath SEND = RustPath.global("std", "marker", "Send");
+    public static RustPath SYNC = RustPath.global("std", "marker", "Sync");
+
+    public static RustPath NONE = RustPath.global("std", "option", "Option", "None");
+    public static RustPath SOME = RustPath.global("std", "option", "Option", "Some");
+
+    public static RustPath STRING = RustPath.global("std", "string", "String");
+
+    public static RustPath ARC = RustPath.global("std", "sync", "Arc");
+
+    public static RustPath arc(RustType innerType) {
+        return ARC.withArgs(List.of(innerType));
+    }
+
+    public static RustPath vec(RustType elementType) {
+        return RustPath.global("std", "vec", "Vec")
+            .withArgs(List.of(elementType));
+    }
 }