pulley: Remove unwrap_uninhabited helper function (#10174)

No longer needed on our MSRV any more.

Author: alexcrichton

pulley/src/decode.rs

@@ -710,14 +710,6 @@ macro_rules! define_extended_decoder {
 }
 for_each_extended_op!(define_extended_decoder);
 
-/// Unwrap a `Result<T, Uninhabited>`.
-/// Always succeeds, since `Uninhabited` is uninhabited.
-pub fn unwrap_uninhabited<T>(res: Result<T, Uninhabited>) -> T {
-    match res {
-        Ok(ok) => ok,
-    }
-}
-
 /// Functions for decoding the operands of an instruction, assuming the opcode
 /// has already been decoded.
 pub mod operands {

pulley/src/interp.rs

@@ -2084,7 +2084,7 @@ impl OpVisitor for Interpreter<'_> {
         // Decode the `PcRelOffset` without tampering with `self.pc` as the
         // jump is relative to `self.pc`.
         let mut tmp = self.pc;
-        let rel = unwrap_uninhabited(PcRelOffset::decode(&mut tmp));
+        let Ok(rel) = PcRelOffset::decode(&mut tmp);
         let offset = isize::try_from(i32::from(rel)).unwrap();
         self.pc = unsafe { self.pc.offset(offset) };
         ControlFlow::Continue(())

pulley/src/interp/match_loop.rs

@@ -16,7 +16,6 @@
 //! will probably need tweaks to make it more performant.
 
 use super::*;
-use crate::decode::unwrap_uninhabited;
 
 impl Interpreter<'_> {
     pub fn run(self) -> Done {
@@ -30,9 +29,9 @@ impl Interpreter<'_> {
             //
             // This will then continue indefinitely until the bytecode says it's
             // done. Note that only trusted bytecode is interpreted here.
-            match unwrap_uninhabited(decoder.decode_one(&mut visitor)) {
-                ControlFlow::Continue(()) => {}
-                ControlFlow::Break(done) => break done,
+            match decoder.decode_one(&mut visitor) {
+                Ok(ControlFlow::Continue(())) => {}
+                Ok(ControlFlow::Break(done)) => break done,
             }
         }
     }

pulley/src/interp/tail_loop.rs

@@ -27,7 +27,7 @@
 //!   at this time but doesn't actually run anywhere.
 
 use super::*;
-use crate::decode::{unwrap_uninhabited, ExtendedOpVisitor};
+use crate::decode::ExtendedOpVisitor;
 use crate::opcode::Opcode;
 use crate::profile::ExecutingPcRef;
 use crate::ExtendedOpcode;
@@ -90,7 +90,7 @@ fn dispatch(
     // opcode.
     let mut debug = debug(state, pc, executing_pc);
     debug.before_visit();
-    let opcode = unwrap_uninhabited(Opcode::decode(debug.bytecode()));
+    let Ok(opcode) = Opcode::decode(debug.bytecode());
     let handler = OPCODE_HANDLER_TABLE[opcode as usize];
     tail_call!(handler(debug.0.state, debug.0.pc, debug.0.executing_pc));
 }
@@ -102,7 +102,7 @@ fn run_extended(
     pc_ref: ExecutingPcRef<'_>,
 ) -> Done {
     let mut i = debug(state, pc, pc_ref);
-    let opcode = unwrap_uninhabited(ExtendedOpcode::decode(i.bytecode()));
+    let Ok(opcode) = ExtendedOpcode::decode(i.bytecode());
     let handler = EXTENDED_OPCODE_HANDLER_TABLE[opcode as usize];
     tail_call!(handler(i.0.state, i.0.pc, i.0.executing_pc));
 }
@@ -171,9 +171,7 @@ macro_rules! define_opcode_handler {
         ) -> Done {
             let mut debug = debug(state, pc, executing_pc);
             $(
-                let ($($field,)*) = unwrap_uninhabited(
-                    crate::decode::operands::$snake_name(debug.0.bytecode())
-                );
+                let Ok(($($field,)*)) = crate::decode::operands::$snake_name(debug.0.bytecode());
             )?
             let result = debug.$snake_name($($($field),*)?);
             debug.after_visit();