Change resource.drop to take a <typeidx>

Author: lukewagner

design/mvp/Binary.md

@@ -281,9 +281,9 @@ Notes:
 ```
 canon    ::= 0x00 0x00 f:<core:funcidx> opts:<opts> ft:<typeidx> => (canon lift f opts type-index-space[ft])
            | 0x01 0x00 f:<funcidx> opts:<opts>                   => (canon lower f opts (core func))
-           | 0x02 t:<typeidx>                                    => (canon resource.new t (core func))
-           | 0x03 t:<valtype>                                    => (canon resource.drop t (core func))
-           | 0x04 t:<typeidx>                                    => (canon resource.rep t (core func))
+           | 0x02 rt:<typeidx>                                   => (canon resource.new rt (core func))
+           | 0x03 rt:<typdidx>                                   => (canon resource.drop rt (core func))
+           | 0x04 rt:<typeidx>                                   => (canon resource.rep rt (core func))
 opts     ::= opt*:vec(<canonopt>)                                => opt*
 canonopt ::= 0x00                                                => string-encoding=utf8
            | 0x01                                                => string-encoding=utf16

design/mvp/CanonicalABI.md

@@ -1596,24 +1596,22 @@ def canon_resource_new(inst, rt, rep):
 
 For a canonical definition:
 ```
-(canon resource.drop $t (core func $f))
+(canon resource.drop $rt (core func $f))
 ```
 validation specifies:
-* `$t` must refer to a handle type `(own $rt)` or `(borrow $rt)`
+* `$rt` must refer to resource type
 * `$f` is given type `(func (param i32))`
 
 Calling `$f` invokes the following function, which removes the handle from the
 current component instance's handle table and, if the handle was owning, calls
 the resource's destructor.
 ```python
-def canon_resource_drop(inst, t, i):
-  h = inst.handles.remove(t.rt, i)
-  trap_if(isinstance(t, Own) and not h.own)
-  trap_if(isinstance(t, Borrow) and h.own)
+def canon_resource_drop(inst, rt, i):
+  h = inst.handles.remove(rt, i)
   if h.own:
-    trap_if(inst is not t.rt.impl and not t.rt.impl.may_enter)
-    if t.rt.dtor:
-      t.rt.dtor(h.rep)
+    trap_if(inst is not rt.impl and not rt.impl.may_enter)
+    if rt.dtor:
+      rt.dtor(h.rep)
 ```
 The `may_enter` guard ensures the non-reentrance [component invariant], since
 a destructor call is analogous to a call to an export.

design/mvp/Explainer.md

@@ -1189,7 +1189,7 @@ async is added to the proposal, [tasks][Future and Stream Types]).
 ```
 canon ::= ...
         | (canon resource.new <typeidx> (core func <id>?))
-        | (canon resource.drop <valtype> (core func <id>?))
+        | (canon resource.drop <typeidx> (core func <id>?))
         | (canon resource.rep <typeidx> (core func <id>?))
 ```
 The `resource.new` built-in has type `[i32] -> [i32]` and creates a new
@@ -1198,9 +1198,8 @@ representation and returning the `i32` index of a new handle pointing to this
 resource.
 
 The `resource.drop` built-in has type `[i32] -> []` and drops a resource handle
-(of type `valtype`, which must be `own` or `borrow`) at the given `i32` index.
-If the dropped handle owns the resource, the resource's `dtor` is called, if
-present.
+(with resource type `typeidx`) at the given `i32` index. If the dropped handle
+owns the resource, the resource's `dtor` is called, if present.
 
 The `resource.rep` built-in has type `[i32] -> [i32]` and returns the `i32`
 representation of the resource (with resource type `typeidx`) pointed to by the

design/mvp/canonical-abi/definitions.py

@@ -1126,14 +1126,12 @@ def canon_resource_new(inst, rt, rep):
 
 ### `canon resource.drop`
 
-def canon_resource_drop(inst, t, i):
-  h = inst.handles.remove(t.rt, i)
-  trap_if(isinstance(t, Own) and not h.own)
-  trap_if(isinstance(t, Borrow) and h.own)
+def canon_resource_drop(inst, rt, i):
+  h = inst.handles.remove(rt, i)
   if h.own:
-    trap_if(inst is not t.rt.impl and not t.rt.impl.may_enter)
-    if t.rt.dtor:
-      t.rt.dtor(h.rep)
+    trap_if(inst is not rt.impl and not rt.impl.may_enter)
+    if rt.dtor:
+      rt.dtor(h.rep)
 
 ### `canon resource.rep`
 

design/mvp/canonical-abi/run_tests.py

@@ -424,7 +424,7 @@ def core_wasm(args):
     assert(canon_resource_rep(inst, rt, 3) == 45)
 
     dtor_value = None
-    canon_resource_drop(inst, Own(rt), 0)
+    canon_resource_drop(inst, rt, 0)
     assert(dtor_value == 42)
     assert(len(inst.handles.table(rt).array) == 4)
     assert(inst.handles.table(rt).array[0] is None)
@@ -437,7 +437,7 @@ def core_wasm(args):
     assert(len(inst.handles.table(rt).free) == 0)
 
     dtor_value = None
-    canon_resource_drop(inst, Borrow(rt), 2)
+    canon_resource_drop(inst, rt, 2)
     assert(dtor_value is None)
     assert(len(inst.handles.table(rt).array) == 4)
     assert(inst.handles.table(rt).array[2] is None)