diff --git a/Cargo.lock b/Cargo.lock
index 7500ac6277..b530153d8c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3592,6 +3592,7 @@ dependencies = [
  "bumpalo",
  "lazy_static",
  "roc_collections",
+ "roc_error_macros",
  "roc_ident",
  "roc_region",
  "snafu",
@@ -3608,6 +3609,7 @@ dependencies = [
  "roc_builtins",
  "roc_can",
  "roc_collections",
+ "roc_error_macros",
  "roc_module",
  "roc_problem",
  "roc_region",
@@ -3792,6 +3794,7 @@ version = "0.1.0"
 dependencies = [
  "bumpalo",
  "roc_collections",
+ "roc_error_macros",
  "roc_module",
  "roc_region",
  "static_assertions",
diff --git a/compiler/module/Cargo.toml b/compiler/module/Cargo.toml
index c05ca69ed1..9b8c272d54 100644
--- a/compiler/module/Cargo.toml
+++ b/compiler/module/Cargo.toml
@@ -9,6 +9,7 @@ license = "UPL-1.0"
 roc_region = { path = "../region" }
 roc_ident = { path = "../ident" }
 roc_collections = { path = "../collections" }
+roc_error_macros = {path = "../../error_macros"}
 bumpalo = { version = "3.8.0", features = ["collections"] }
 lazy_static = "1.4.0"
 static_assertions = "1.1.0"
diff --git a/compiler/module/src/ident.rs b/compiler/module/src/ident.rs
index 4f4cb22196..73a5fc9737 100644
--- a/compiler/module/src/ident.rs
+++ b/compiler/module/src/ident.rs
@@ -59,7 +59,9 @@ pub enum TagName {
     Closure(Symbol),
 }
 
-static_assertions::assert_eq_size!((usize, usize, u64), TagName);
+roc_error_macros::assert_sizeof_aarch64!(TagName, 24);
+roc_error_macros::assert_sizeof_wasm!(TagName, 16);
+roc_error_macros::assert_sizeof_default!(TagName, 24);
 
 impl TagName {
     pub fn as_ident_str(&self, interns: &Interns, home: ModuleId) -> IdentStr {
diff --git a/compiler/mono/Cargo.toml b/compiler/mono/Cargo.toml
index 969bd4e256..5bdf3723fa 100644
--- a/compiler/mono/Cargo.toml
+++ b/compiler/mono/Cargo.toml
@@ -17,6 +17,7 @@ roc_std = { path = "../../roc_std" }
 roc_problem = { path = "../problem" }
 roc_builtins = { path = "../builtins" }
 roc_target = { path = "../roc_target" }
+roc_error_macros = {path="../../error_macros"}
 ven_pretty = { path = "../../vendor/pretty" }
 morphic_lib = { path = "../../vendor/morphic_lib" }
 bumpalo = { version = "3.8.0", features = ["collections"] }
diff --git a/compiler/mono/src/ir.rs b/compiler/mono/src/ir.rs
index 01b0a78389..0e0c39019a 100644
--- a/compiler/mono/src/ir.rs
+++ b/compiler/mono/src/ir.rs
@@ -34,18 +34,26 @@ pub fn pretty_print_ir_symbols() -> bool {
 // if it went up, maybe check that the change is really required
 
 // i128 alignment is different on arm
-#[cfg(target_arch = "aarch64")]
-static_assertions::assert_eq_size!([u64; 4], Literal);
-#[cfg(not(target_arch = "aarch64"))]
-static_assertions::assert_eq_size!([u64; 3], Literal);
-static_assertions::assert_eq_size!(([u64; 4], [usize; 6]), Expr);
-#[cfg(not(target_arch = "aarch64"))]
-static_assertions::assert_eq_size!(([u64; 5], [usize; 14]), Stmt);
-#[cfg(target_arch = "aarch64")]
-static_assertions::assert_eq_size!([u64; 20], Stmt);
-static_assertions::assert_eq_size!([usize; 6], ProcLayout);
-static_assertions::assert_eq_size!(([u64; 3], [usize; 4]), Call);
-static_assertions::assert_eq_size!(([u64; 3], [usize; 2]), CallType);
+roc_error_macros::assert_sizeof_aarch64!(Literal, 4 * 8);
+roc_error_macros::assert_sizeof_aarch64!(Expr, 10 * 8);
+roc_error_macros::assert_sizeof_aarch64!(Stmt, 20 * 8);
+roc_error_macros::assert_sizeof_aarch64!(ProcLayout, 6 * 8);
+roc_error_macros::assert_sizeof_aarch64!(Call, 7 * 8);
+roc_error_macros::assert_sizeof_aarch64!(CallType, 5 * 8);
+
+roc_error_macros::assert_sizeof_wasm!(Literal, 24);
+roc_error_macros::assert_sizeof_wasm!(Expr, 56);
+roc_error_macros::assert_sizeof_wasm!(Stmt, 96);
+roc_error_macros::assert_sizeof_wasm!(ProcLayout, 24);
+roc_error_macros::assert_sizeof_wasm!(Call, 40);
+roc_error_macros::assert_sizeof_wasm!(CallType, 32);
+
+roc_error_macros::assert_sizeof_default!(Literal, 3 * 8);
+roc_error_macros::assert_sizeof_default!(Expr, 10 * 8);
+roc_error_macros::assert_sizeof_default!(Stmt, 19 * 8);
+roc_error_macros::assert_sizeof_default!(ProcLayout, 6 * 8);
+roc_error_macros::assert_sizeof_default!(Call, 7 * 8);
+roc_error_macros::assert_sizeof_default!(CallType, 5 * 8);
 
 macro_rules! return_on_layout_error {
     ($env:expr, $layout_result:expr) => {
diff --git a/compiler/types/Cargo.toml b/compiler/types/Cargo.toml
index 97cd23ac45..550cb5f333 100644
--- a/compiler/types/Cargo.toml
+++ b/compiler/types/Cargo.toml
@@ -9,6 +9,7 @@ edition = "2018"
 roc_collections = { path = "../collections" }
 roc_region = { path = "../region" }
 roc_module = { path = "../module" }
+roc_error_macros = {path="../../error_macros"}
 ven_ena = { path = "../../vendor/ena" }
 bumpalo = { version = "3.8.0", features = ["collections"] }
 static_assertions = "1.1.0"
diff --git a/compiler/types/src/subs.rs b/compiler/types/src/subs.rs
index 051845d03b..7dac3c50c7 100644
--- a/compiler/types/src/subs.rs
+++ b/compiler/types/src/subs.rs
@@ -9,12 +9,15 @@ use ven_ena::unify::{InPlace, Snapshot, UnificationTable, UnifyKey};
 // if your changes cause this number to go down, great!
 // please change it to the lower number.
 // if it went up, maybe check that the change is really required
-static_assertions::assert_eq_size!([u64; 6], Descriptor);
-static_assertions::assert_eq_size!([u64; 4], Content);
-static_assertions::assert_eq_size!([u64; 3], FlatType);
-static_assertions::assert_eq_size!(([usize; 4], [u64; 2]), Problem);
-static_assertions::assert_eq_size!([u8; 12], UnionTags);
-static_assertions::assert_eq_size!([u64; 2], RecordFields);
+roc_error_macros::assert_sizeof_all!(Descriptor, 6 * 8);
+roc_error_macros::assert_sizeof_all!(Content, 4 * 8);
+roc_error_macros::assert_sizeof_all!(FlatType, 3 * 8);
+roc_error_macros::assert_sizeof_all!(UnionTags, 12);
+roc_error_macros::assert_sizeof_all!(RecordFields, 2 * 8);
+
+roc_error_macros::assert_sizeof_aarch64!(Problem, 6 * 8);
+roc_error_macros::assert_sizeof_wasm!(Problem, 32);
+roc_error_macros::assert_sizeof_default!(Problem, 6 * 8);
 
 #[derive(Clone, Copy, Hash, PartialEq, Eq)]
 pub struct Mark(i32);
@@ -1623,11 +1626,14 @@ impl From<Content> for Descriptor {
     }
 }
 
-static_assertions::assert_eq_size!([u64; 4], Content);
-static_assertions::assert_eq_size!([usize; 4], (Variable, Option<Lowercase>));
-static_assertions::assert_eq_size!([u64; 3], (Symbol, AliasVariables, Variable));
-static_assertions::assert_eq_size!([u8; 8], AliasVariables);
-static_assertions::assert_eq_size!([u64; 3], FlatType);
+roc_error_macros::assert_sizeof_all!(Content, 4 * 8);
+roc_error_macros::assert_sizeof_all!((Symbol, AliasVariables, Variable), 3 * 8);
+roc_error_macros::assert_sizeof_all!(AliasVariables, 8);
+roc_error_macros::assert_sizeof_all!(FlatType, 3 * 8);
+
+roc_error_macros::assert_sizeof_aarch64!((Variable, Option<Lowercase>), 4 * 8);
+roc_error_macros::assert_sizeof_wasm!((Variable, Option<Lowercase>), 4 * 4);
+roc_error_macros::assert_sizeof_all!((Variable, Option<Lowercase>), 4 * 8);
 
 #[derive(Clone, Debug)]
 pub enum Content {
@@ -1765,8 +1771,6 @@ impl Content {
     }
 }
 
-static_assertions::assert_eq_size!([u64; 3], FlatType);
-
 #[derive(Clone, Debug)]
 pub enum FlatType {
     Apply(Symbol, VariableSubsSlice),
diff --git a/error_macros/src/lib.rs b/error_macros/src/lib.rs
index d9b2e0e9a3..39aeca5aa0 100644
--- a/error_macros/src/lib.rs
+++ b/error_macros/src/lib.rs
@@ -29,3 +29,39 @@ macro_rules! user_error {
         std::process::exit(1);
     })
 }
+
+/// Assert that a type has the expected size on ARM
+#[macro_export]
+macro_rules! assert_sizeof_aarch64 {
+    ($t: ty, $expected_size: expr) => {
+        #[cfg(target_arch = "aarch64")]
+        static_assertions::assert_eq_size!($t, [u8; $expected_size]);
+    };
+}
+
+/// Assert that a type has the expected size in Wasm
+#[macro_export]
+macro_rules! assert_sizeof_wasm {
+    ($t: ty, $expected_size: expr) => {
+        #[cfg(target_family = "wasm")]
+        static_assertions::assert_eq_size!($t, [u8; $expected_size]);
+    };
+}
+
+/// Assert that a type has the expected size on any target not covered above
+/// In practice we use this for x86_64, and add specific macros for other platforms
+#[macro_export]
+macro_rules! assert_sizeof_default {
+    ($t: ty, $expected_size: expr) => {
+        #[cfg(not(any(target_family = "wasm", target_arch = "aarch64")))]
+        static_assertions::assert_eq_size!($t, [u8; $expected_size]);
+    };
+}
+
+/// Assert that a type has the expected size on all targets
+#[macro_export]
+macro_rules! assert_sizeof_all {
+    ($t: ty, $expected_size: expr) => {
+        static_assertions::assert_eq_size!($t, [u8; $expected_size]);
+    };
+}