Auto merge of #27296 - jroesch:type-macros, r=huonw

This pull request implements the functionality for [RFC 873](https://github.com/rust-lang/rfcs/blob/master/text/0873-type-macros.md). This is currently just an update of @freebroccolo's branch from January, the corresponding commits are linked in each commit message.

@nikomatsakis and I had talked about updating the macro language to support a lifetime fragment specifier, and it is possible to do that work on this branch as well. If so we can (collectively) talk about it next week during the pre-RustCamp work week.

1 files changed, 20 insertions, 0 deletions

diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs
index b2cff3ed53c..d4b5e67eeb4 100644
--- a/src/libsyntax/ext/base.rs
+++ b/src/libsyntax/ext/base.rs
@@ -290,6 +290,10 @@ pub trait MacResult {
     fn make_stmts(self: Box<Self>) -> Option<SmallVector<P<ast::Stmt>>> {
         make_stmts_default!(self)
     }
+
+    fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
+        None
+    }
 }
 
 macro_rules! make_MacEager {
@@ -322,6 +326,7 @@ make_MacEager! {
     items: SmallVector<P<ast::Item>>,
     impl_items: SmallVector<P<ast::ImplItem>>,
     stmts: SmallVector<P<ast::Stmt>>,
+    ty: P<ast::Ty>,
 }
 
 impl MacResult for MacEager {
@@ -359,6 +364,10 @@ impl MacResult for MacEager {
         }
         None
     }
+
+    fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
+        self.ty
+    }
 }
 
 /// Fill-in macro expansion result, to allow compilation to continue
@@ -405,15 +414,24 @@ impl DummyResult {
         }
     }
 
+    pub fn raw_ty(sp: Span) -> P<ast::Ty> {
+        P(ast::Ty {
+            id: ast::DUMMY_NODE_ID,
+            node: ast::TyInfer,
+            span: sp
+        })
+    }
 }
 
 impl MacResult for DummyResult {
     fn make_expr(self: Box<DummyResult>) -> Option<P<ast::Expr>> {
         Some(DummyResult::raw_expr(self.span))
     }
+
     fn make_pat(self: Box<DummyResult>) -> Option<P<ast::Pat>> {
         Some(P(DummyResult::raw_pat(self.span)))
     }
+
     fn make_items(self: Box<DummyResult>) -> Option<SmallVector<P<ast::Item>>> {
         // this code needs a comment... why not always just return the Some() ?
         if self.expr_only {
@@ -422,6 +440,7 @@ impl MacResult for DummyResult {
             Some(SmallVector::zero())
         }
     }
+
     fn make_impl_items(self: Box<DummyResult>) -> Option<SmallVector<P<ast::ImplItem>>> {
         if self.expr_only {
             None
@@ -429,6 +448,7 @@ impl MacResult for DummyResult {
             Some(SmallVector::zero())
         }
     }
+
     fn make_stmts(self: Box<DummyResult>) -> Option<SmallVector<P<ast::Stmt>>> {
         Some(SmallVector::one(P(
             codemap::respan(self.span,