Rip it out

My type ascription
Oh rip it out
Ah
If you think we live too much then
You can sacrifice diagnostics
Don't mix your garbage
Into my syntax
So many weird hacks keep diagnostics alive
Yet I don't even step outside
So many bad diagnostics keep tyasc alive
Yet tyasc doesn't even bother to survive!

compiler/rustc_ast/src/ast.rs

@@ -1589,7 +1589,6 @@ pub enum ClosureBinder {
 pub struct MacCall {
     pub path: Path,
     pub args: P<DelimArgs>,
-    pub prior_type_ascription: Option<(Span, bool)>,
 }
 
 impl MacCall {

compiler/rustc_ast/src/mut_visit.rs

@@ -631,7 +631,7 @@ pub fn noop_visit_attribute<T: MutVisitor>(attr: &mut Attribute, vis: &mut T) {
 }
 
 pub fn noop_visit_mac<T: MutVisitor>(mac: &mut MacCall, vis: &mut T) {
-    let MacCall { path, args, prior_type_ascription: _ } = mac;
+    let MacCall { path, args } = mac;
     vis.visit_path(path);
     visit_delim_args(args, vis);
 }

compiler/rustc_ast/src/util/parser.rs

@@ -53,8 +53,6 @@ pub enum AssocOp {
     DotDot,
     /// `..=` range
     DotDotEq,
-    /// `:`
-    Colon,
 }
 
 #[derive(PartialEq, Debug)]
@@ -96,7 +94,6 @@ impl AssocOp {
             token::DotDotEq => Some(DotDotEq),
             // DotDotDot is no longer supported, but we need some way to display the error
             token::DotDotDot => Some(DotDotEq),
-            token::Colon => Some(Colon),
             // `<-` should probably be `< -`
             token::LArrow => Some(Less),
             _ if t.is_keyword(kw::As) => Some(As),
@@ -133,7 +130,7 @@ impl AssocOp {
     pub fn precedence(&self) -> usize {
         use AssocOp::*;
         match *self {
-            As | Colon => 14,
+            As => 14,
             Multiply | Divide | Modulus => 13,
             Add | Subtract => 12,
             ShiftLeft | ShiftRight => 11,
@@ -156,7 +153,7 @@ impl AssocOp {
             Assign | AssignOp(_) => Fixity::Right,
             As | Multiply | Divide | Modulus | Add | Subtract | ShiftLeft | ShiftRight | BitAnd
             | BitXor | BitOr | Less | Greater | LessEqual | GreaterEqual | Equal | NotEqual
-            | LAnd | LOr | Colon => Fixity::Left,
+            | LAnd | LOr => Fixity::Left,
             DotDot | DotDotEq => Fixity::None,
         }
     }
@@ -166,8 +163,9 @@ impl AssocOp {
         match *self {
             Less | Greater | LessEqual | GreaterEqual | Equal | NotEqual => true,
             Assign | AssignOp(_) | As | Multiply | Divide | Modulus | Add | Subtract
-            | ShiftLeft | ShiftRight | BitAnd | BitXor | BitOr | LAnd | LOr | DotDot | DotDotEq
-            | Colon => false,
+            | ShiftLeft | ShiftRight | BitAnd | BitXor | BitOr | LAnd | LOr | DotDot | DotDotEq => {
+                false
+            }
         }
     }
 
@@ -177,7 +175,7 @@ impl AssocOp {
             Assign | AssignOp(_) => true,
             Less | Greater | LessEqual | GreaterEqual | Equal | NotEqual | As | Multiply
             | Divide | Modulus | Add | Subtract | ShiftLeft | ShiftRight | BitAnd | BitXor
-            | BitOr | LAnd | LOr | DotDot | DotDotEq | Colon => false,
+            | BitOr | LAnd | LOr | DotDot | DotDotEq => false,
         }
     }
 
@@ -202,7 +200,7 @@ impl AssocOp {
             BitOr => Some(BinOpKind::BitOr),
             LAnd => Some(BinOpKind::And),
             LOr => Some(BinOpKind::Or),
-            Assign | AssignOp(_) | As | DotDot | DotDotEq | Colon => None,
+            Assign | AssignOp(_) | As | DotDot | DotDotEq => None,
         }
     }
 
@@ -223,10 +221,9 @@ impl AssocOp {
             Greater | // `{ 42 } > 3`
             GreaterEqual | // `{ 42 } >= 3`
             AssignOp(_) | // `{ 42 } +=`
-            As | // `{ 42 } as usize`
             // Equal | // `{ 42 } == { 42 }`    Accepting these here would regress incorrect
-            // NotEqual | // `{ 42 } != { 42 }` struct literals parser recovery.
-            Colon, // `{ 42 }: usize`
+            // NotEqual | // `{ 42 } != { 42 }  struct literals parser recovery.
+            As // `{ 42 } as usize`
         )
     }
 }
@@ -254,7 +251,6 @@ pub enum ExprPrecedence {
     Binary(BinOpKind),
 
     Cast,
-    Type,
 
     Assign,
     AssignOp,
@@ -313,7 +309,6 @@ impl ExprPrecedence {
             // Binop-like expr kinds, handled by `AssocOp`.
             ExprPrecedence::Binary(op) => AssocOp::from_ast_binop(op).precedence() as i8,
             ExprPrecedence::Cast => AssocOp::As.precedence() as i8,
-            ExprPrecedence::Type => AssocOp::Colon.precedence() as i8,
 
             ExprPrecedence::Assign |
             ExprPrecedence::AssignOp => AssocOp::Assign.precedence() as i8,