librustc: Implement simple `where` clauses.

These `where` clauses are accepted everywhere generics are currently
accepted and desugar during type collection to the type parameter bounds
we have today.

A new keyword, `where`, has been added. Therefore, this is a breaking
change. Change uses of `where` to other identifiers.

[breaking-change]

3 files changed, 30 insertions, 30 deletions

diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index c5d3c73c9bc..68e1529fb17 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -363,7 +363,7 @@ impl Clean<Item> for doctree::Module {
 
         // determine if we should display the inner contents or
         // the outer `mod` item for the source code.
-        let where = {
+        let whence = {
             let ctxt = super::ctxtkey.get().unwrap();
             let cm = ctxt.sess().codemap();
             let outer = cm.lookup_char_pos(self.where_outer.lo);
@@ -380,7 +380,7 @@ impl Clean<Item> for doctree::Module {
         Item {
             name: Some(name),
             attrs: self.attrs.clean(),
-            source: where.clean(),
+            source: whence.clean(),
             visibility: self.vis.clean(),
             stability: self.stab.clean(),
             def_id: ast_util::local_def(self.id),
@@ -781,7 +781,7 @@ impl Clean<Item> for doctree::Function {
         Item {
             name: Some(self.name.clean()),
             attrs: self.attrs.clean(),
-            source: self.where.clean(),
+            source: self.whence.clean(),
             visibility: self.vis.clean(),
             stability: self.stab.clean(),
             def_id: ast_util::local_def(self.id),
@@ -917,7 +917,7 @@ impl Clean<Item> for doctree::Trait {
         Item {
             name: Some(self.name.clean()),
             attrs: self.attrs.clean(),
-            source: self.where.clean(),
+            source: self.whence.clean(),
             def_id: ast_util::local_def(self.id),
             visibility: self.vis.clean(),
             stability: self.stab.clean(),
@@ -1397,7 +1397,7 @@ impl Clean<Item> for doctree::Struct {
         Item {
             name: Some(self.name.clean()),
             attrs: self.attrs.clean(),
-            source: self.where.clean(),
+            source: self.whence.clean(),
             def_id: ast_util::local_def(self.id),
             visibility: self.vis.clean(),
             stability: self.stab.clean(),
@@ -1443,7 +1443,7 @@ impl Clean<Item> for doctree::Enum {
         Item {
             name: Some(self.name.clean()),
             attrs: self.attrs.clean(),
-            source: self.where.clean(),
+            source: self.whence.clean(),
             def_id: ast_util::local_def(self.id),
             visibility: self.vis.clean(),
             stability: self.stab.clean(),
@@ -1466,7 +1466,7 @@ impl Clean<Item> for doctree::Variant {
         Item {
             name: Some(self.name.clean()),
             attrs: self.attrs.clean(),
-            source: self.where.clean(),
+            source: self.whence.clean(),
             visibility: self.vis.clean(),
             stability: self.stab.clean(),
             def_id: ast_util::local_def(self.id),
@@ -1652,7 +1652,7 @@ impl Clean<Item> for doctree::Typedef {
         Item {
             name: Some(self.name.clean()),
             attrs: self.attrs.clean(),
-            source: self.where.clean(),
+            source: self.whence.clean(),
             def_id: ast_util::local_def(self.id.clone()),
             visibility: self.vis.clean(),
             stability: self.stab.clean(),
@@ -1702,7 +1702,7 @@ impl Clean<Item> for doctree::Static {
         Item {
             name: Some(self.name.clean()),
             attrs: self.attrs.clean(),
-            source: self.where.clean(),
+            source: self.whence.clean(),
             def_id: ast_util::local_def(self.id),
             visibility: self.vis.clean(),
             stability: self.stab.clean(),
@@ -1748,7 +1748,7 @@ impl Clean<Item> for doctree::Impl {
         Item {
             name: None,
             attrs: self.attrs.clean(),
-            source: self.where.clean(),
+            source: self.whence.clean(),
             def_id: ast_util::local_def(self.id),
             visibility: self.vis.clean(),
             stability: self.stab.clean(),
@@ -2115,12 +2115,12 @@ impl Clean<Item> for doctree::Macro {
         Item {
             name: Some(format!("{}!", self.name.clean())),
             attrs: self.attrs.clean(),
-            source: self.where.clean(),
+            source: self.whence.clean(),
             visibility: ast::Public.clean(),
             stability: self.stab.clean(),
             def_id: ast_util::local_def(self.id),
             inner: MacroItem(Macro {
-                source: self.where.to_src(),
+                source: self.whence.to_src(),
             }),
         }
     }
diff --git a/src/librustdoc/doctree.rs b/src/librustdoc/doctree.rs
index a5ead46384a..da45321e7fd 100644
--- a/src/librustdoc/doctree.rs
+++ b/src/librustdoc/doctree.rs
@@ -93,7 +93,7 @@ pub struct Struct {
     pub generics: ast::Generics,
     pub attrs: Vec<ast::Attribute>,
     pub fields: Vec<ast::StructField>,
-    pub where: Span,
+    pub whence: Span,
 }
 
 pub struct Enum {
@@ -103,7 +103,7 @@ pub struct Enum {
     pub generics: ast::Generics,
     pub attrs: Vec<ast::Attribute>,
     pub id: NodeId,
-    pub where: Span,
+    pub whence: Span,
     pub name: Ident,
 }
 
@@ -114,7 +114,7 @@ pub struct Variant {
     pub id: ast::NodeId,
     pub vis: ast::Visibility,
     pub stab: Option<attr::Stability>,
-    pub where: Span,
+    pub whence: Span,
 }
 
 pub struct Function {
@@ -125,7 +125,7 @@ pub struct Function {
     pub vis: ast::Visibility,
     pub stab: Option<attr::Stability>,
     pub fn_style: ast::FnStyle,
-    pub where: Span,
+    pub whence: Span,
     pub generics: ast::Generics,
 }
 
@@ -135,7 +135,7 @@ pub struct Typedef {
     pub name: Ident,
     pub id: ast::NodeId,
     pub attrs: Vec<ast::Attribute>,
-    pub where: Span,
+    pub whence: Span,
     pub vis: ast::Visibility,
     pub stab: Option<attr::Stability>,
 }
@@ -149,7 +149,7 @@ pub struct Static {
     pub vis: ast::Visibility,
     pub stab: Option<attr::Stability>,
     pub id: ast::NodeId,
-    pub where: Span,
+    pub whence: Span,
 }
 
 pub struct Trait {
@@ -159,7 +159,7 @@ pub struct Trait {
     pub parents: Vec<ast::TraitRef>,
     pub attrs: Vec<ast::Attribute>,
     pub id: ast::NodeId,
-    pub where: Span,
+    pub whence: Span,
     pub vis: ast::Visibility,
     pub stab: Option<attr::Stability>,
 }
@@ -170,7 +170,7 @@ pub struct Impl {
     pub for_: ast::P<ast::Ty>,
     pub items: Vec<ast::ImplItem>,
     pub attrs: Vec<ast::Attribute>,
-    pub where: Span,
+    pub whence: Span,
     pub vis: ast::Visibility,
     pub stab: Option<attr::Stability>,
     pub id: ast::NodeId,
@@ -180,7 +180,7 @@ pub struct Macro {
     pub name: Ident,
     pub id: ast::NodeId,
     pub attrs: Vec<ast::Attribute>,
-    pub where: Span,
+    pub whence: Span,
     pub stab: Option<attr::Stability>,
 }
 
diff --git a/src/librustdoc/visit_ast.rs b/src/librustdoc/visit_ast.rs
index f7ccad79fda..b67b3c394d6 100644
--- a/src/librustdoc/visit_ast.rs
+++ b/src/librustdoc/visit_ast.rs
@@ -91,7 +91,7 @@ impl<'a> RustdocVisitor<'a> {
             attrs: item.attrs.iter().map(|x| *x).collect(),
             generics: generics.clone(),
             fields: sd.fields.iter().map(|x| (*x).clone()).collect(),
-            where: item.span
+            whence: item.span
         }
     }
 
@@ -107,7 +107,7 @@ impl<'a> RustdocVisitor<'a> {
                 stab: self.stability(x.node.id),
                 id: x.node.id,
                 kind: x.node.kind.clone(),
-                where: x.span,
+                whence: x.span,
             });
         }
         Enum {
@@ -118,7 +118,7 @@ impl<'a> RustdocVisitor<'a> {
             generics: params.clone(),
             attrs: it.attrs.iter().map(|x| *x).collect(),
             id: it.id,
-            where: it.span,
+            whence: it.span,
         }
     }
 
@@ -133,7 +133,7 @@ impl<'a> RustdocVisitor<'a> {
             attrs: item.attrs.iter().map(|x| *x).collect(),
             decl: fd.clone(),
             name: item.ident,
-            where: item.span,
+            whence: item.span,
             generics: gen.clone(),
             fn_style: *fn_style,
         }
@@ -297,7 +297,7 @@ impl<'a> RustdocVisitor<'a> {
                     name: item.ident,
                     id: item.id,
                     attrs: item.attrs.iter().map(|x| *x).collect(),
-                    where: item.span,
+                    whence: item.span,
                     vis: item.vis,
                     stab: self.stability(item.id),
                 };
@@ -311,7 +311,7 @@ impl<'a> RustdocVisitor<'a> {
                     id: item.id,
                     name: item.ident,
                     attrs: item.attrs.iter().map(|x| *x).collect(),
-                    where: item.span,
+                    whence: item.span,
                     vis: item.vis,
                     stab: self.stability(item.id),
                 };
@@ -325,7 +325,7 @@ impl<'a> RustdocVisitor<'a> {
                     parents: tr.iter().map(|x| (*x).clone()).collect(),
                     id: item.id,
                     attrs: item.attrs.iter().map(|x| *x).collect(),
-                    where: item.span,
+                    whence: item.span,
                     vis: item.vis,
                     stab: self.stability(item.id),
                 };
@@ -339,7 +339,7 @@ impl<'a> RustdocVisitor<'a> {
                     items: items.iter().map(|x| *x).collect(),
                     attrs: item.attrs.iter().map(|x| *x).collect(),
                     id: item.id,
-                    where: item.span,
+                    whence: item.span,
                     vis: item.vis,
                     stab: self.stability(item.id),
                 };
@@ -360,7 +360,7 @@ impl<'a> RustdocVisitor<'a> {
             id: item.id,
             attrs: item.attrs.iter().map(|x| *x).collect(),
             name: item.ident,
-            where: item.span,
+            whence: item.span,
             stab: self.stability(item.id),
         }
     }