assert_clone in shallow #[derive(Copy,Clone)]

durka · durka · commit 6712c0213db7 · 2016-04-18T16:33:43.000-04:00
diff --git a/src/libcore/clone.rs b/src/libcore/clone.rs
@@ -75,6 +75,15 @@ pub trait Clone : Sized {
     }
 }
 
+// FIXME(aburka): this method is used solely by #[deriving] to
+// assert that every component of a type implements Clone.
+//
+// This should never be called by user code.
+#[doc(hidden)]
+#[inline(always)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn assert_receiver_is_clone<T: Clone + ?Sized>(_: &T) {}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, T: ?Sized> Clone for &'a T {
     /// Returns a shallow copy of the reference.
diff --git a/src/libsyntax_ext/deriving/clone.rs b/src/libsyntax_ext/deriving/clone.rs
@@ -19,6 +19,8 @@ use syntax::ext::build::AstBuilder;
 use syntax::parse::token::InternedString;
 use syntax::ptr::P;
 
+enum Mode { Assert, Clone }
+
 pub fn expand_deriving_clone(cx: &mut ExtCtxt,
                              span: Span,
                              mitem: &MetaItem,
@@ -39,25 +41,30 @@ pub fn expand_deriving_clone(cx: &mut ExtCtxt,
     let substructure;
     let nested_match;
     match *item {
-        Annotatable::Item(ref item) => {
-            match item.node {
+        Annotatable::Item(ref annitem) => {
+            match annitem.node {
                 ItemKind::Struct(_, Generics { ref ty_params, .. }) |
                 ItemKind::Enum(_, Generics { ref ty_params, .. })
-                    if ty_params.is_empty() && attr::contains_name(&item.attrs, "derive_Copy") => {
+                    if ty_params.is_empty()
+                        && attr::contains_name(&annitem.attrs, "derive_Copy") => {
 
                     bounds = vec![Literal(path_std!(cx, core::marker::Copy))];
-                    substructure = combine_substructure(Box::new(|c, s, _| {
-                        cs_shallow_clone(c, s)
+                    substructure = combine_substructure(Box::new(|c, s, sub| {
+                        cs_deep_clone("Clone", c, s, sub, Mode::Assert)
                     }));
-                    nested_match = false;
+                    nested_match = enclose(|c, s, sub| {
+                        let inner = cs_shallow_clone(c, s);
+                        c.expr_block(c.block_all(s, vec![c.stmt_expr(sub)], Some(inner)))
+                        //^ FIXME(aburka): this generates an extra set of {} braces
+                    });
                 }
 
                 _ => {
                     bounds = vec![];
                     substructure = combine_substructure(Box::new(|c, s, sub| {
-                        cs_deep_clone("Clone", c, s, sub)
+                        cs_deep_clone("Clone", c, s, sub, Mode::Clone)
                     }));
-                    nested_match = true;
+                    nested_match = None;
                 }
             }
         }
@@ -101,10 +108,14 @@ fn cs_shallow_clone(cx: &mut ExtCtxt, trait_span: Span) -> P<Expr> {
 fn cs_deep_clone(
     name: &str,
     cx: &mut ExtCtxt, trait_span: Span,
-    substr: &Substructure) -> P<Expr> {
+    substr: &Substructure,
+    mode: Mode) -> P<Expr> {
     let ctor_path;
     let all_fields;
-    let fn_path = cx.std_path(&["clone", "Clone", "clone"]);
+    let fn_path = match mode {
+        Mode::Assert => cx.std_path(&["clone", "assert_receiver_is_clone"]),
+        Mode::Clone  => cx.std_path(&["clone", "Clone", "clone"]),
+    };
     let subcall = |field: &FieldInfo| {
         let args = vec![cx.expr_addr_of(field.span, field.self_.clone())];
 
@@ -134,29 +145,41 @@ fn cs_deep_clone(
         }
     }
 
-    match *vdata {
-        VariantData::Struct(..) => {
-            let fields = all_fields.iter().map(|field| {
-                let ident = match field.name {
-                    Some(i) => i,
-                    None => {
-                        cx.span_bug(trait_span,
-                                    &format!("unnamed field in normal struct in \
-                                             `derive({})`", name))
-                    }
-                };
-                cx.field_imm(field.span, ident, subcall(field))
-            }).collect::<Vec<_>>();
-
-            cx.expr_struct(trait_span, ctor_path, fields)
+    match mode {
+        Mode::Assert => {
+            cx.expr_block(cx.block(trait_span,
+                                   all_fields.iter()
+                                             .map(subcall)
+                                             .map(|e| cx.stmt_expr(e))
+                                             .collect(),
+                                   None))
         }
-        VariantData::Tuple(..) => {
-            let subcalls = all_fields.iter().map(subcall).collect();
-            let path = cx.expr_path(ctor_path);
-            cx.expr_call(trait_span, path, subcalls)
-        }
-        VariantData::Unit(..) => {
-            cx.expr_path(ctor_path)
+        Mode::Clone => {
+            match *vdata {
+                VariantData::Struct(..) => {
+                    let fields = all_fields.iter().map(|field| {
+                        let ident = match field.name {
+                            Some(i) => i,
+                            None => {
+                                cx.span_bug(trait_span,
+                                            &format!("unnamed field in normal struct in \
+                                                     `derive({})`", name))
+                            }
+                        };
+                        cx.field_imm(field.span, ident, subcall(field))
+                    }).collect::<Vec<_>>();
+
+                    cx.expr_struct(trait_span, ctor_path, fields)
+                }
+                VariantData::Tuple(..) => {
+                    let subcalls = all_fields.iter().map(subcall).collect();
+                    let path = cx.expr_path(ctor_path);
+                    cx.expr_call(trait_span, path, subcalls)
+                }
+                VariantData::Unit(..) => {
+                    cx.expr_path(ctor_path)
+                }
+            }
         }
     }
 }
diff --git a/src/libsyntax_ext/deriving/cmp/eq.rs b/src/libsyntax_ext/deriving/cmp/eq.rs
@@ -58,7 +58,7 @@ pub fn expand_deriving_eq(cx: &mut ExtCtxt,
                 name: "assert_receiver_is_total_eq",
                 generics: LifetimeBounds::empty(),
                 explicit_self: borrowed_explicit_self(),
-                nested_match: true,
+                nested_match: None,
                 args: vec!(),
                 ret_ty: nil_ty(),
                 attributes: attrs,
diff --git a/src/libsyntax_ext/deriving/cmp/ord.rs b/src/libsyntax_ext/deriving/cmp/ord.rs
@@ -38,7 +38,7 @@ pub fn expand_deriving_ord(cx: &mut ExtCtxt,
                 name: "cmp",
                 generics: LifetimeBounds::empty(),
                 explicit_self: borrowed_explicit_self(),
-                nested_match: true,
+                nested_match: None,
                 args: vec!(borrowed_self()),
                 ret_ty: Literal(path_std!(cx, core::cmp::Ordering)),
                 attributes: attrs,
diff --git a/src/libsyntax_ext/deriving/cmp/partial_eq.rs b/src/libsyntax_ext/deriving/cmp/partial_eq.rs
@@ -69,7 +69,7 @@ pub fn expand_deriving_partial_eq(cx: &mut ExtCtxt,
                 name: $name,
                 generics: LifetimeBounds::empty(),
                 explicit_self: borrowed_explicit_self(),
-                nested_match: true,
+                nested_match: None,
                 args: vec!(borrowed_self()),
                 ret_ty: Literal(path_local!(bool)),
                 attributes: attrs,
diff --git a/src/libsyntax_ext/deriving/cmp/partial_ord.rs b/src/libsyntax_ext/deriving/cmp/partial_ord.rs
@@ -34,7 +34,7 @@ pub fn expand_deriving_partial_ord(cx: &mut ExtCtxt,
                 name: $name,
                 generics: LifetimeBounds::empty(),
                 explicit_self: borrowed_explicit_self(),
-                nested_match: true,
+                nested_match: None,
                 args: vec!(borrowed_self()),
                 ret_ty: Literal(path_local!(bool)),
                 attributes: attrs,
@@ -59,7 +59,7 @@ pub fn expand_deriving_partial_ord(cx: &mut ExtCtxt,
         name: "partial_cmp",
         generics: LifetimeBounds::empty(),
         explicit_self: borrowed_explicit_self(),
-        nested_match: true,
+        nested_match: None,
         args: vec![borrowed_self()],
         ret_ty: ret_ty,
         attributes: attrs,
diff --git a/src/libsyntax_ext/deriving/debug.rs b/src/libsyntax_ext/deriving/debug.rs
@@ -41,7 +41,7 @@ pub fn expand_deriving_debug(cx: &mut ExtCtxt,
                 name: "fmt",
                 generics: LifetimeBounds::empty(),
                 explicit_self: borrowed_explicit_self(),
-                nested_match: true,
+                nested_match: None,
                 args: vec!(fmtr),
                 ret_ty: Literal(path_std!(cx, core::fmt::Result)),
                 attributes: Vec::new(),
diff --git a/src/libsyntax_ext/deriving/decodable.rs b/src/libsyntax_ext/deriving/decodable.rs
@@ -73,7 +73,7 @@ fn expand_deriving_decodable_imp(cx: &mut ExtCtxt,
                                   vec![Path::new_(vec!(krate, "Decoder"), None, vec!(), true)])]
                 },
                 explicit_self: None,
-                nested_match: true,
+                nested_match: None,
                 args: vec!(Ptr(Box::new(Literal(Path::new_local(typaram))),
                            Borrowed(None, Mutability::Mutable))),
                 ret_ty: Literal(Path::new_(
diff --git a/src/libsyntax_ext/deriving/default.rs b/src/libsyntax_ext/deriving/default.rs
@@ -38,7 +38,7 @@ pub fn expand_deriving_default(cx: &mut ExtCtxt,
                 name: "default",
                 generics: LifetimeBounds::empty(),
                 explicit_self: None,
-                nested_match: true,
+                nested_match: None,
                 args: Vec::new(),
                 ret_ty: Self_,
                 attributes: attrs,
diff --git a/src/libsyntax_ext/deriving/encodable.rs b/src/libsyntax_ext/deriving/encodable.rs
@@ -149,7 +149,7 @@ fn expand_deriving_encodable_imp(cx: &mut ExtCtxt,
                                   vec![Path::new_(vec![krate, "Encoder"], None, vec!(), true)])]
                 },
                 explicit_self: borrowed_explicit_self(),
-                nested_match: true,
+                nested_match: None,
                 args: vec!(Ptr(Box::new(Literal(Path::new_local(typaram))),
                            Borrowed(None, Mutability::Mutable))),
                 ret_ty: Literal(Path::new_(
diff --git a/src/libsyntax_ext/deriving/generic/mod.rs b/src/libsyntax_ext/deriving/generic/mod.rs
@@ -249,7 +249,7 @@ pub struct MethodDef<'a> {
 
     /// Whether the function structure is a nested `match` statement with the result of
     /// combine_substructe() inside, or just the result of combine_substructure()
-    pub nested_match: bool,
+    pub nested_match: Option<RefCell<EncloseFunc<'a>>>,
 
     /// Arguments other than the self argument
     pub args: Vec<Ty<'a>>,
@@ -331,6 +331,9 @@ pub enum SubstructureFields<'a> {
 pub type CombineSubstructureFunc<'a> =
     Box<FnMut(&mut ExtCtxt, Span, &Substructure) -> P<Expr> + 'a>;
 
+pub type EncloseFunc<'a> =
+    Box<FnMut(&mut ExtCtxt, Span, P<Expr>) -> P<Expr> + 'a>;
+
 /// Deal with non-matching enum variants.  The tuple is a list of
 /// identifiers (one for each `Self` argument, which could be any of the
 /// variants since they have been collapsed together) and the identifiers
@@ -344,6 +347,13 @@ pub fn combine_substructure<'a>(f: CombineSubstructureFunc<'a>)
     RefCell::new(f)
 }
 
+pub fn enclose<'a, F>(f: F)
+    -> Option<RefCell<EncloseFunc<'a>>>
+    where F: FnMut(&mut ExtCtxt, Span, P<Expr>) -> P<Expr> + 'a
+{
+    Some(RefCell::new(Box::new(f)))
+}
+
 /// This method helps to extract all the type parameters referenced from a
 /// type. For a type parameter `<T>`, it looks for either a `TyPath` that
 /// is not global and starts with `T`, or a `TyQPath`.
@@ -861,7 +871,14 @@ impl<'a> MethodDef<'a> {
                      abi: Abi,
                      explicit_self: ast::ExplicitSelf,
                      arg_types: Vec<(Ident, P<ast::Ty>)> ,
-                     body: P<Expr>) -> ast::ImplItem {
+                     mut body: P<Expr>) -> ast::ImplItem {
+
+        if self.nested_match.is_some() {
+            let mut f = self.nested_match.as_ref().unwrap().borrow_mut();
+            let f: &mut _ = &mut *f;
+            body = f(cx, trait_.span, body);
+        }
+
         // create the generics that aren't for Self
         let fn_generics = self.generics.to_generics(cx, trait_.span, type_ident, generics);
 
@@ -988,14 +1005,12 @@ impl<'a> MethodDef<'a> {
             nonself_args,
             &Struct(struct_def, fields));
 
-        if self.nested_match {
-            // make a series of nested matches, to destructure the
-            // structs. This is actually right-to-left, but it shouldn't
-            // matter.
-            for (arg_expr, pat) in self_args.iter().zip(patterns) {
-                body = cx.expr_match(trait_.span, arg_expr.clone(),
-                                         vec!( cx.arm(trait_.span, vec!(pat.clone()), body) ))
-            }
+        // make a series of nested matches, to destructure the
+        // structs. This is actually right-to-left, but it shouldn't
+        // matter.
+        for (arg_expr, pat) in self_args.iter().zip(patterns) {
+            body = cx.expr_match(trait_.span, arg_expr.clone(),
+                                     vec!( cx.arm(trait_.span, vec!(pat.clone()), body) ))
         }
 
         body
diff --git a/src/libsyntax_ext/deriving/hash.rs b/src/libsyntax_ext/deriving/hash.rs
@@ -47,7 +47,7 @@ pub fn expand_deriving_hash(cx: &mut ExtCtxt,
                                   vec![path_std!(cx, core::hash::Hasher)])],
                 },
                 explicit_self: borrowed_explicit_self(),
-                nested_match: true,
+                nested_match: None,
                 args: vec!(Ptr(Box::new(Literal(arg)), Borrowed(None, Mutability::Mutable))),
                 ret_ty: nil_ty(),
                 attributes: vec![],
diff --git a/src/test/auxiliary/custom_derive_plugin.rs b/src/test/auxiliary/custom_derive_plugin.rs
@@ -55,7 +55,7 @@ fn expand(cx: &mut ExtCtxt,
                 generics: LifetimeBounds::empty(),
                 explicit_self: borrowed_explicit_self(),
                 args: vec![],
-                nested_match: true,
+                nested_match: None,
                 ret_ty: Literal(Path::new_local("isize")),
                 attributes: vec![],
                 is_unsafe: false,
diff --git a/src/test/auxiliary/custom_derive_plugin_attr.rs b/src/test/auxiliary/custom_derive_plugin_attr.rs
@@ -57,7 +57,7 @@ fn expand(cx: &mut ExtCtxt,
                 generics: LifetimeBounds::empty(),
                 explicit_self: borrowed_explicit_self(),
                 args: vec![],
-                nested_match: true,
+                nested_match: None,
                 ret_ty: Literal(Path::new_local("isize")),
                 attributes: vec![],
                 is_unsafe: false,
diff --git a/src/test/run-make/expand-derive/Makefile b/src/test/run-make/expand-derive/Makefile
@@ -1,21 +1,10 @@
 -include ../tools.mk
 
-REPLACEMENT := s/[0-9][0-9]*\#[0-9][0-9]*//g
-
 all:
 	# pretty-expand both input.rs and input_pp.rs
 	$(RUSTC) -o $(TMPDIR)/input.pretty -Z unstable-options \
-		--pretty expanded,hygiene input.rs
+		--pretty expanded input.rs
 	$(RUSTC) -o $(TMPDIR)/input_pp.pretty -Z unstable-options \
-		--pretty expanded,hygiene input_pp.rs
-
-	# the name/ctxt numbers are very internals-dependent and thus
-	# change relatively frequently, and testing for their exact values
-	# them will fail annoyingly, so we just remove them
-	#
-	# (These need to be out-of-place because OSX/BSD & GNU sed
-	# differ.)
-	sed "$(REPLACEMENT)" $(TMPDIR)/input.pretty    > $(TMPDIR)/input.replaced
-	sed "$(REPLACEMENT)" $(TMPDIR)/input_pp.pretty > $(TMPDIR)/input_pp.replaced
+		--pretty expanded input_pp.rs
 
-	diff -u $(TMPDIR)/input.replaced $(TMPDIR)/input_pp.replaced
+	diff -u $(TMPDIR)/input.pretty $(TMPDIR)/input_pp.pretty
diff --git a/src/test/run-make/expand-derive/input_pp.rs b/src/test/run-make/expand-derive/input_pp.rs
@@ -19,7 +19,16 @@ struct A {
 #[allow(unused_qualifications)]
 impl ::clone::Clone for A {
     #[inline]
-    fn clone(&self) -> A { *self }
+    fn clone(&self) -> A {
+        {
+            match *self {
+                A { a: ref __self_0_0 } => {
+                    ::clone::assert_receiver_is_clone(&(*__self_0_0));
+                }
+            };
+            *self
+        }
+    }
 }
 #[automatically_derived]
 #[allow(unused_qualifications)]
