Add information about the syntax used in ranges

... or ..=

src/librustc/hir/lowering.rs

@@ -1869,7 +1869,7 @@ impl<'a> LoweringContext<'a> {
 
     fn lower_range_end(&mut self, e: &RangeEnd) -> hir::RangeEnd {
         match *e {
-            RangeEnd::Included => hir::RangeEnd::Included,
+            RangeEnd::Included(_) => hir::RangeEnd::Included,
             RangeEnd::Excluded => hir::RangeEnd::Excluded,
         }
     }

src/libsyntax/ast.rs

@@ -538,10 +538,16 @@ pub enum BindingMode {
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub enum RangeEnd {
-    Included,
+    Included(RangeSyntax),
     Excluded,
 }
 
+#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+pub enum RangeSyntax {
+    DotDotDot,
+    DotDotEq,
+}
+
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub enum PatKind {
     /// Represents a wildcard pattern (`_`)
@@ -578,7 +584,7 @@ pub enum PatKind {
     Ref(P<Pat>, Mutability),
     /// A literal
     Lit(P<Expr>),
-    /// A range pattern, e.g. `1...2` or `1..2`
+    /// A range pattern, e.g. `1...2`, `1..=2` or `1..2`
     Range(P<Expr>, P<Expr>, RangeEnd),
     /// `[a, b, ..i, y, z]` is represented as:
     ///     `PatKind::Slice(box [a, b], Some(i), box [y, z])`

src/libsyntax/parse/parser.rs

@@ -38,7 +38,7 @@ use ast::{Ty, TyKind, TypeBinding, TyParam, TyParamBounds};
 use ast::{ViewPath, ViewPathGlob, ViewPathList, ViewPathSimple};
 use ast::{Visibility, WhereClause};
 use ast::{BinOpKind, UnOp};
-use ast::RangeEnd;
+use ast::{RangeEnd, RangeSyntax};
 use {ast, attr};
 use codemap::{self, CodeMap, Spanned, respan};
 use syntax_pos::{self, Span, BytePos};
@@ -3557,7 +3557,8 @@ impl<'a> Parser<'a> {
                     token::DotDotDot | token::DotDotEq | token::DotDot => {
                         let end_kind = match self.token {
                             token::DotDot => RangeEnd::Excluded,
-                            token::DotDotDot | token::DotDotEq => RangeEnd::Included,
+                            token::DotDotDot => RangeEnd::Included(RangeSyntax::DotDotDot),
+                            token::DotDotEq => RangeEnd::Included(RangeSyntax::DotDotEq),
                             _ => panic!("can only parse `..`/`...`/`..=` for ranges \
                                          (checked above)"),
                         };
@@ -3600,10 +3601,12 @@ impl<'a> Parser<'a> {
                     Ok(begin) => {
                         if self.eat(&token::DotDotDot) {
                             let end = self.parse_pat_range_end()?;
-                            pat = PatKind::Range(begin, end, RangeEnd::Included);
+                            pat = PatKind::Range(begin, end,
+                                    RangeEnd::Included(RangeSyntax::DotDotDot));
                         } else if self.eat(&token::DotDotEq) {
                             let end = self.parse_pat_range_end()?;
-                            pat = PatKind::Range(begin, end, RangeEnd::Included);
+                            pat = PatKind::Range(begin, end,
+                                    RangeEnd::Included(RangeSyntax::DotDotEq));
                         } else if self.eat(&token::DotDot) {
                             let end = self.parse_pat_range_end()?;
                             pat = PatKind::Range(begin, end, RangeEnd::Excluded);

src/libsyntax/print/pprust.rs

@@ -11,7 +11,7 @@
 pub use self::AnnNode::*;
 
 use abi::{self, Abi};
-use ast::{self, BlockCheckMode, PatKind, RangeEnd};
+use ast::{self, BlockCheckMode, PatKind, RangeEnd, RangeSyntax};
 use ast::{SelfKind, RegionTyParamBound, TraitTyParamBound, TraitBoundModifier};
 use ast::Attribute;
 use util::parser::{self, AssocOp, Fixity};
@@ -2590,7 +2590,8 @@ impl<'a> State<'a> {
                 self.print_expr(begin)?;
                 self.s.space()?;
                 match *end_kind {
-                    RangeEnd::Included => self.s.word("...")?,
+                    RangeEnd::Included(RangeSyntax::DotDotDot) => self.s.word("...")?,
+                    RangeEnd::Included(RangeSyntax::DotDotEq) => self.s.word("..=")?,
                     RangeEnd::Excluded => self.s.word("..")?,
                 }
                 self.print_expr(end)?;