logical left, right shifts wip

compiler/rustc_parse/messages.ftl

@@ -397,6 +397,11 @@ parse_invalid_literal_suffix_on_tuple_index = suffixes on a tuple index are inva
     .tuple_exception_line_2 = on proc macros, you'll want to use `syn::Index::from` or `proc_macro::Literal::*_unsuffixed` for code that will desugar to tuple field access
     .tuple_exception_line_3 = see issue #60210 <https://github.com/rust-lang/rust/issues/60210> for more information
 
+
+parser_invalid_shift_operator = invalid shift operator `{$invalid}`
+    .logical_left_shift_operator_invalid = `<<<` is not a valid left shift operator, consider shifting normally and fixing the sign as needed
+    .logical_right_shift_operator_invalid = `>>>` is not a valid right shift operator, consider casting to an unsigned integer and right shifting normally
+
 parse_invalid_logical_operator = `{$incorrect}` is not a logical operator
     .note = unlike in e.g., Python and PHP, `&&` and `||` are used for logical operators
     .use_amp_amp_for_conjunction = use `&&` to perform logical conjunction

compiler/rustc_parse/src/errors.rs

@@ -156,6 +156,25 @@ pub(crate) enum InvalidComparisonOperatorSub {
     Spaceship(#[primary_span] Span),
 }
 
+#[derive(Diagnostic)]
+#[diag(parse_invalid_shift_operator)]
+#[note]
+pub(crate) struct InvalidShiftOperator {
+    #[primary_span]
+    pub Span: Span,
+    pub invalid: String,
+    #[subdiagnostic]
+    pub sub: InvalidShiftOperatorSub
+}
+
+#[derive(SessionSubdiagnostic)]
+pub enum InvalidShiftOperatorSub {
+    #[label(parser_left_shift_operator_invalid)]
+    LogicalLeftShift(#[primary_span] Span),
+    #[label(parser_logical_right_shift_operator)]
+    LogicalRightShift(#[primary_span] Span),
+}
+
 #[derive(Diagnostic)]
 #[diag(parse_invalid_logical_operator)]
 #[note]

compiler/rustc_parse/src/parser/expr.rs

@@ -271,6 +271,29 @@ impl<'a> Parser<'a> {
                 self.bump();
             }
 
+            // Look for the logical right shift operator (`>>>`) and recover
+            if op.node == AssocOp::ShiftRight && self.token.kind == token::Gt && self.prev_token.span.hi() == self.token.span.lo() {
+                let sp = op.span.to(self.token.span);
+                self.sess.emit_err(errors::InvalidShiftOperator {
+                    span: sp,
+                    invalid: ">>>".into(),
+                    sub: errors::InvalidShiftOperatorSub::LogicalRightShift(sp),
+                });
+                self.bump();
+            }
+
+            // Look for the logical left shift operator (`<<<`) and recover
+            if op.node == AssocOp::ShiftLeft && self.token.kind == token::Lt && self.prev_token.span.hi() == self.token.span.lo() {
+                let sp = op.span.to(self.token.span);
+                self.sess.emit_err(errors::InvalidShiftOperator {
+                    span: sp,
+                    invalid: "<<<".into(),
+                    sub: errors::InvalidShiftOperatorSub::LogicalLeftShift(sp),
+                });
+                self.bump();
+            }
+
+
             if self.prev_token == token::BinOp(token::Plus)
                 && self.token == token::BinOp(token::Plus)
                 && self.prev_token.span.between(self.token.span).is_empty()

src/test/ui/operator-recovery/logical-left-shift.rs

@@ -0,0 +1,4 @@
+fn main() {
+    println!("{}", 1 <<< 2);
+    //~^ERROR invalid shift operator `<<<`
+}

src/test/ui/operator-recovery/logical-left-shift.stderr

@@ -0,0 +1,8 @@
+error: invalid shift operator `<<<`
+  --> $DIR/logical-left-shift.rs:2:22
+   |
+LL |     println!("{}", 1 <<< 2);
+   |                      ^^^ `<<<` is not a valid left shift operator, consider shifting normally and fixing the sign as needed.
+
+error: aborting due to previous error
+

src/test/ui/operator-recovery/logical-right-shift.rs

@@ -0,0 +1,4 @@
+fn main() {
+    println!("{}", 1 >>> 2);
+    //~^ERROR invalid shift operator `>>>`
+}

src/test/ui/operator-recovery/logical-right-shift.stderr

@@ -0,0 +1,8 @@
+error: invalid shift operator `>>>`
+  --> $DIR/logical-right-shift.rs:2:22
+   |
+LL |     println!("{}", 1 >>> 2);
+   |                      ^^^ `>>>` is not a valid right shift operator, consider casting to an unsigned integer and right shifting normally.
+
+error: aborting due to previous error
+