Ignore drop check bools when testing for legal generator types

src/librustc/ich/impls_mir.rs

@@ -27,6 +27,7 @@ impl_stable_hash_for!(struct mir::LocalDecl<'tcx> {
     ty,
     name,
     source_info,
+    internal,
     is_user_variable
 });
 impl_stable_hash_for!(struct mir::UpvarDecl { debug_name, by_ref });

src/librustc/mir/mod.rs

@@ -411,6 +411,10 @@ pub struct LocalDecl<'tcx> {
     /// True if this corresponds to a user-declared local variable.
     pub is_user_variable: bool,
 
+    /// True if this an internal local.
+    /// Such locals are not checked against the legal types in a generator.
+    pub internal: bool,
+
     /// Type of this local.
     pub ty: Ty<'tcx>,
 
@@ -436,6 +440,23 @@ impl<'tcx> LocalDecl<'tcx> {
                 span,
                 scope: ARGUMENT_VISIBILITY_SCOPE
             },
+            internal: false,
+            is_user_variable: false
+        }
+    }
+
+    /// Create a new `LocalDecl` for a internal temporary.
+    #[inline]
+    pub fn new_internal(ty: Ty<'tcx>, span: Span) -> Self {
+        LocalDecl {
+            mutability: Mutability::Mut,
+            ty,
+            name: None,
+            source_info: SourceInfo {
+                span,
+                scope: ARGUMENT_VISIBILITY_SCOPE
+            },
+            internal: true,
             is_user_variable: false
         }
     }
@@ -452,6 +473,7 @@ impl<'tcx> LocalDecl<'tcx> {
                 span,
                 scope: ARGUMENT_VISIBILITY_SCOPE
             },
+            internal: false,
             name: None,     // FIXME maybe we do want some name here?
             is_user_variable: false
         }

src/librustc/mir/visit.rs

@@ -654,6 +654,7 @@ macro_rules! make_mir_visitor {
                     ref $($mutability)* ty,
                     name: _,
                     ref $($mutability)* source_info,
+                    internal: _,
                     is_user_variable: _,
                 } = *local_decl;
 

src/librustc_mir/build/matches/mod.rs

@@ -712,6 +712,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
             ty: var_ty.clone(),
             name: Some(name),
             source_info: source_info,
+            internal: false,
             is_user_variable: true,
         });
         self.var_indices.insert(var_id, var);

src/librustc_mir/build/mod.rs

@@ -521,6 +521,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     span: pattern.map_or(self.fn_span, |pat| pat.span)
                 },
                 name: name,
+                internal: false,
                 is_user_variable: false,
             });
         }

src/librustc_mir/shim.rs

@@ -128,6 +128,7 @@ fn temp_decl(mutability: Mutability, ty: Ty, span: Span) -> LocalDecl {
     LocalDecl {
         mutability, ty, name: None,
         source_info: SourceInfo { scope: ARGUMENT_VISIBILITY_SCOPE, span },
+        internal: false,
         is_user_variable: false
     }
 }

src/librustc_mir/transform/elaborate_drops.rs

@@ -314,7 +314,7 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
         let patch = &mut self.patch;
         debug!("create_drop_flag({:?})", self.mir.span);
         self.drop_flags.entry(index).or_insert_with(|| {
-            patch.new_temp(tcx.types.bool, span)
+            patch.new_internal(tcx.types.bool, span)
         });
     }
 

src/librustc_mir/transform/generator.rs

@@ -263,6 +263,7 @@ fn replace_result_variable<'tcx>(ret_ty: Ty<'tcx>,
         ty: ret_ty,
         name: None,
         source_info,
+        internal: false,
         is_user_variable: false,
     };
     let new_ret_local = Local::new(mir.local_decls.len());
@@ -314,7 +315,7 @@ fn compute_layout<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     let allowed = tcx.erase_regions(&interior.as_slice());
 
     for (local, decl) in mir.local_decls.iter_enumerated() {
-        if !live_locals.contains(&local) {
+        if !live_locals.contains(&local) || decl.internal {
             continue;
         }
         if !allowed.contains(&decl.ty) {
@@ -340,6 +341,7 @@ fn compute_layout<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
             ty: unit,
             name: None,
             source_info,
+            internal: false,
             is_user_variable: false,
         };
         remap.insert(local, (var.ty, upvar_len + 1 + idx));
@@ -482,6 +484,7 @@ fn generate_drop<'a, 'tcx>(
         ty: tcx.mk_nil(),
         name: None,
         source_info,
+        internal: false,
         is_user_variable: false,
     };
 
@@ -496,6 +499,7 @@ fn generate_drop<'a, 'tcx>(
         }),
         name: None,
         source_info,
+        internal: false,
         is_user_variable: false,
     };
 

src/librustc_mir/util/patch.rs

@@ -101,6 +101,13 @@ impl<'tcx> MirPatch<'tcx> {
         Local::new(index as usize)
     }
 
+    pub fn new_internal(&mut self, ty: Ty<'tcx>, span: Span) -> Local {
+        let index = self.next_local;
+        self.next_local += 1;
+        self.new_locals.push(LocalDecl::new_internal(ty, span));
+        Local::new(index as usize)
+    }
+
     pub fn new_block(&mut self, data: BasicBlockData<'tcx>) -> BasicBlock {
         let block = BasicBlock::new(self.patch_map.len());
         debug!("MirPatch: new_block: {:?}: {:?}", block, data);

src/librustc_typeck/check/generator_interior.rs

@@ -66,9 +66,6 @@ pub fn find_interior<'a, 'gcx, 'tcx>(fcx: &'a FnCtxt<'a, 'gcx, 'tcx>,
     };
     intravisit::walk_body(&mut visitor, body);
 
-    // FIXME: Drop elaboration can insert bool types in the generator
-    visitor.types.insert(fcx.tcx.types.bool);
-
     // Deduplicate types
     let set: FxHashSet<_> = visitor.types.into_iter()
         .map(|t| fcx.resolve_type_vars_if_possible(&t))