Auto merge of #35403 - scottcarr:lvalue_refactor, r=nikomatsakis

refactor lvalue_ty to be method of lvalue

Currently `Mir` (and `MirContext`) implement a method `lvalue_ty` (and actually many more `foo_ty`).  But this should be a method of `Lvalue`.

If you have an `lvalue` and you want to get its type, the natural thing to write is:

```
lvalue.ty()
```

Of course it needs context, but still:

```
lvalue.ty(mir, tcx)
```

Makes more sense than

```
mir.lvalue_ty(lvalue, tcx)
```

I actually think we should go a step farther and have traits so we could get the type of some value generically, but that's up for debate.  The thing I'm running into a lot in the compiler is I have a value of type `Foo` and I know that there is some related type `Bar` which I can get through some combination of method calls, but it's often not as direct as I would imagine.  Unless you already know the code, its not clear why you would look in `Mir` for a method to get the type of an `Lvalue`.

2 files changed, 6 insertions, 6 deletions

diff --git a/src/librustc_borrowck/borrowck/mir/elaborate_drops.rs b/src/librustc_borrowck/borrowck/mir/elaborate_drops.rs
index 623ea60c5a6..f6e9484eda1 100644
--- a/src/librustc_borrowck/borrowck/mir/elaborate_drops.rs
+++ b/src/librustc_borrowck/borrowck/mir/elaborate_drops.rs
@@ -185,7 +185,7 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
     {
         match self.move_data().move_paths[path].content {
             MovePathContent::Lvalue(ref lvalue) => {
-                let ty = self.mir.lvalue_ty(self.tcx, lvalue).to_ty(self.tcx);
+                let ty = lvalue.ty(self.mir, self.tcx).to_ty(self.tcx);
                 debug!("path_needs_drop({:?}, {:?} : {:?})", path, lvalue, ty);
 
                 self.tcx.type_needs_drop_given_env(ty, self.param_env())
@@ -555,7 +555,7 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
 
         let mut fields = fields;
         fields.retain(|&(ref lvalue, _)| {
-            let ty = self.mir.lvalue_ty(self.tcx, lvalue).to_ty(self.tcx);
+            let ty = lvalue.ty(self.mir, self.tcx).to_ty(self.tcx);
             self.tcx.type_needs_drop_given_env(ty, self.param_env())
         });
 
@@ -706,7 +706,7 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
     /// This creates a "drop ladder" that drops the needed fields of the
     /// ADT, both in the success case or if one of the destructors fail.
     fn open_drop<'a>(&mut self, c: &DropCtxt<'a, 'tcx>) -> BasicBlock {
-        let ty = self.mir.lvalue_ty(self.tcx, c.lvalue).to_ty(self.tcx);
+        let ty = c.lvalue.ty(self.mir, self.tcx).to_ty(self.tcx);
         match ty.sty {
             ty::TyStruct(def, substs) | ty::TyEnum(def, substs) => {
                 self.open_drop_for_adt(c, def, substs)
@@ -892,7 +892,7 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
         // dataflow can create unneeded children in some cases
         // - be sure to ignore them.
 
-        let ty = self.mir.lvalue_ty(self.tcx, c.lvalue).to_ty(self.tcx);
+        let ty = c.lvalue.ty(self.mir, self.tcx).to_ty(self.tcx);
 
         match ty.sty {
             ty::TyStruct(def, _) | ty::TyEnum(def, _) => {
diff --git a/src/librustc_borrowck/borrowck/mir/mod.rs b/src/librustc_borrowck/borrowck/mir/mod.rs
index 7481b15685e..7c912e8bac6 100644
--- a/src/librustc_borrowck/borrowck/mir/mod.rs
+++ b/src/librustc_borrowck/borrowck/mir/mod.rs
@@ -256,7 +256,7 @@ fn move_path_children_matching<'tcx, F>(move_paths: &MovePathData<'tcx>,
 fn lvalue_contents_drop_state_cannot_differ<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                                       mir: &Mir<'tcx>,
                                                       lv: &repr::Lvalue<'tcx>) -> bool {
-    let ty = mir.lvalue_ty(tcx, lv).to_ty(tcx);
+    let ty = lv.ty(mir, tcx).to_ty(tcx);
     match ty.sty {
         ty::TyArray(..) | ty::TySlice(..) | ty::TyRef(..) | ty::TyRawPtr(..) => {
             debug!("lvalue_contents_drop_state_cannot_differ lv: {:?} ty: {:?} refd => false",
@@ -355,7 +355,7 @@ fn drop_flag_effects_for_location<'a, 'tcx, F>(
 
         // don't move out of non-Copy things
         if let MovePathContent::Lvalue(ref lvalue) = move_data.move_paths[path].content {
-            let ty = mir.lvalue_ty(tcx, lvalue).to_ty(tcx);
+            let ty = lvalue.ty(mir, tcx).to_ty(tcx);
             if !ty.moves_by_default(tcx, param_env, DUMMY_SP) {
                 continue;
             }