use expect_none and unwrap_none where it makes sense

src/eval.rs

@@ -177,10 +177,7 @@ pub fn create_ecx<'mir, 'tcx: 'mir>(
         }
     }
 
-    assert!(
-        args.next().is_none(),
-        "start lang item has more arguments than expected"
-    );
+    args.next().expect_none("start lang item has more arguments than expected");
 
     // Set the last_error to 0
     let errno_layout = ecx.layout_of(ecx.tcx.types.u32)?;

src/lib.rs

@@ -1,4 +1,5 @@
 #![feature(rustc_private)]
+#![feature(option_expect_none, option_unwrap_none)]
 
 #![warn(rust_2018_idioms)]
 #![allow(clippy::cast_lossless)]

src/machine.rs

@@ -244,10 +244,7 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'tcx> {
         ecx.write_scalar(Scalar::from_uint(align, arg.layout.size), arg)?;
 
         // No more arguments.
-        assert!(
-            args.next().is_none(),
-            "`exchange_malloc` lang item has more arguments than expected"
-        );
+        args.next().expect_none("`exchange_malloc` lang item has more arguments than expected");
         Ok(())
     }
 

src/shims/foreign_items.rs

@@ -349,10 +349,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                 let arg_dest = this.local_place(arg_local)?;
                 this.write_scalar(data, arg_dest)?;
 
-                assert!(
-                    args.next().is_none(),
-                    "__rust_maybe_catch_panic argument has more arguments than expected"
-                );
+                args.next().expect_none("__rust_maybe_catch_panic argument has more arguments than expected");
 
                 // We ourselves will return `0`, eventually (because we will not return if we paniced).
                 this.write_null(dest)?;

src/shims/fs.rs

@@ -7,6 +7,7 @@ use rustc::ty::layout::Size;
 use crate::stacked_borrows::Tag;
 use crate::*;
 
+#[derive(Debug)]
 pub struct FileHandle {
     file: File,
 }
@@ -103,7 +104,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         let fd = options.open(path).map(|file| {
             let mut fh = &mut this.machine.file_handler;
             fh.low += 1;
-            fh.handles.insert(fh.low, FileHandle { file });
+            fh.handles.insert(fh.low, FileHandle { file }).unwrap_none();
             fh.low
         });
 
@@ -175,7 +176,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                     .map(|buffer| handle.file.read(buffer))
             });
             // Reinsert the file handle
-            this.machine.file_handler.handles.insert(fd, handle);
+            this.machine.file_handler.handles.insert(fd, handle).unwrap_none();
             this.consume_result(bytes?.map(|bytes| bytes as i64))
         })
     }
@@ -204,7 +205,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                     .get_bytes(&*this.tcx, buf, Size::from_bytes(count))
                     .map(|bytes| handle.file.write(bytes).map(|bytes| bytes as i64))
             });
-            this.machine.file_handler.handles.insert(fd, handle);
+            this.machine.file_handler.handles.insert(fd, handle).unwrap_none();
             this.consume_result(bytes?)
         })
     }

src/shims/intrinsics.rs

@@ -356,7 +356,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                         _ => {
                             // Do it in memory
                             let mplace = this.force_allocation(dest)?;
-                            assert!(mplace.meta.is_none());
+                            mplace.meta.unwrap_none();
                             // not a zst, must be valid pointer
                             let ptr = mplace.ptr.to_ptr()?;
                             // we know the return place is in-bounds
@@ -547,7 +547,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                         _ => {
                             // Do it in memory
                             let mplace = this.force_allocation(dest)?;
-                            assert!(mplace.meta.is_none());
+                            mplace.meta.unwrap_none();
                             let ptr = mplace.ptr.to_ptr()?;
                             // We know the return place is in-bounds
                             this.memory

src/shims/tls.rs

@@ -53,7 +53,7 @@ impl<'tcx> TlsData<'tcx> {
                 data: None,
                 dtor,
             },
-        );
+        ).unwrap_none();
         trace!("New TLS key allocated: {} with dtor {:?}", new_key, dtor);
         new_key
     }

src/stacked_borrows.rs

@@ -172,7 +172,7 @@ impl GlobalState {
     pub fn new_call(&mut self) -> CallId {
         let id = self.next_call_id;
         trace!("new_call: Assigning ID {}", id);
-        self.active_calls.insert(id);
+        assert!(self.active_calls.insert(id));
         self.next_call_id = NonZeroU64::new(id.get() + 1).unwrap();
         id
     }
@@ -189,7 +189,7 @@ impl GlobalState {
         self.base_ptr_ids.get(&id).copied().unwrap_or_else(|| {
             let tag = Tag::Tagged(self.new_ptr());
             trace!("New allocation {:?} has base tag {:?}", id, tag);
-            self.base_ptr_ids.insert(id, tag);
+            self.base_ptr_ids.insert(id, tag).unwrap_none();
             tag
         })
     }