diff --git a/src/proc/typifier.rs b/src/proc/typifier.rs
index 7a1d7a46e0..6e237ee5a1 100644
--- a/src/proc/typifier.rs
+++ b/src/proc/typifier.rs
@@ -189,10 +189,14 @@ pub enum ResolveError {
     FunctionNotDefined { name: String },
     #[error("Function without return type")]
     FunctionReturnsVoid,
-    #[error("Type is not found in the given immutable arena")]
-    TypeNotFound,
     #[error("Incompatible operands: {0}")]
     IncompatibleOperands(String),
+    #[error("Local var {0:?} doesn't exist")]
+    LocalVariableNotFound(Handle<crate::LocalVariable>),
+    #[error("Global var {0:?} doesn't exist")]
+    GlobalVariableNotFound(Handle<crate::GlobalVariable>),
+    #[error("Function argument {0} doesn't exist")]
+    FunctionArgumentNotFound(u32),
 }
 
 pub struct ResolveContext<'a> {
@@ -430,10 +434,17 @@ impl<'a> ResolveContext<'a> {
             },
             crate::Expression::Compose { ty, .. } => TypeResolution::Handle(ty),
             crate::Expression::FunctionArgument(index) => {
-                TypeResolution::Handle(self.arguments[index as usize].ty)
+                let arg = self
+                    .arguments
+                    .get(index as usize)
+                    .ok_or(ResolveError::FunctionArgumentNotFound(index))?;
+                TypeResolution::Handle(arg.ty)
             }
             crate::Expression::GlobalVariable(h) => {
-                let var = &self.global_vars[h];
+                let var = self
+                    .global_vars
+                    .try_get(h)
+                    .ok_or(ResolveError::GlobalVariableNotFound(h))?;
                 if var.class == crate::StorageClass::Handle {
                     TypeResolution::Handle(var.ty)
                 } else {
@@ -444,7 +455,10 @@ impl<'a> ResolveContext<'a> {
                 }
             }
             crate::Expression::LocalVariable(h) => {
-                let var = &self.local_vars[h];
+                let var = self
+                    .local_vars
+                    .try_get(h)
+                    .ok_or(ResolveError::LocalVariableNotFound(h))?;
                 TypeResolution::Value(Ti::Pointer {
                     base: var.ty,
                     class: crate::StorageClass::Function,
diff --git a/src/valid/function.rs b/src/valid/function.rs
index 0254775ec5..66f5965dbb 100644
--- a/src/valid/function.rs
+++ b/src/valid/function.rs
@@ -819,13 +819,7 @@ impl super::Validator {
         module: &crate::Module,
         mod_info: &ModuleInfo,
     ) -> Result<FunctionInfo, WithSpan<FunctionError>> {
-        #[cfg(feature = "validate")]
-        let mut info = mod_info
-            .process_function(fun, module, self.flags)
-            .map_err(WithSpan::into_other)?;
-
-        #[cfg(not(feature = "validate"))]
-        let info = mod_info.process_function(fun, module, self.flags)?;
+        let mut info = mod_info.process_function(fun, module, self.flags)?;
 
         #[cfg(feature = "validate")]
         for (var_handle, var) in fun.local_variables.iter() {
diff --git a/src/valid/mod.rs b/src/valid/mod.rs
index f703bb916c..a7e57a8667 100644
--- a/src/valid/mod.rs
+++ b/src/valid/mod.rs
@@ -240,7 +240,11 @@ impl Validator {
                 }
             }
             crate::ConstantInner::Composite { ty, ref components } => {
-                match types.get_handle(ty).ok_or(ConstantError::InvalidType)?.inner {
+                match types
+                    .get_handle(ty)
+                    .ok_or(ConstantError::InvalidType)?
+                    .inner
+                {
                     crate::TypeInner::Array {
                         size: crate::ArraySize::Constant(size_handle),
                         ..