Panic on unreachable code

Author: andyleiserson

naga/src/back/hlsl/mod.rs

@@ -471,8 +471,6 @@ pub enum Error {
     ResolveArraySizeError(#[from] proc::ResolveArraySizeError),
     #[error("entry point with stage {0:?} and name '{1}' not found")]
     EntryPointNotFound(ir::ShaderStage, String),
-    #[error("Internal error: reached unreachable code: {0}")]
-    Unreachable(String),
 }
 
 #[derive(PartialEq, Eq, Hash)]

naga/src/back/hlsl/storage.rs

@@ -343,9 +343,7 @@ impl<W: fmt::Write> super::Writer<'_, W> {
                 &temp_resolution
             }
             StoreValue::TempColumnAccess { .. } => {
-                return Err(Error::Unreachable(
-                    "attempting write_storage_store for TempColumnAccess".into(),
-                ));
+                unreachable!("attempting write_storage_store for TempColumnAccess");
             }
         };
         match *ty_resolution.inner_with(&module.types) {
@@ -409,9 +407,9 @@ impl<W: fmt::Write> super::Writer<'_, W> {
                             // working around the borrow checker in `self.write_expr`
                             let var_name = &self.names[&NameKey::GlobalVariable(var_handle)];
                             let StoreValue::TempAccess { member_index, .. } = value else {
-                                return Err(Error::Unreachable(
-                                    "write_storage_store within_struct but not TempAccess".into(),
-                                ));
+                                unreachable!(
+                                    "write_storage_store within_struct but not TempAccess"
+                                );
                             };
                             let column_value = StoreValue::TempColumnAccess {
                                 depth: level.0, // note not incrementing, b/c no temp