diff options
| -rw-r--r-- | compiler/rustc_parse/src/parser/stmt.rs | 8 | ||||
| -rw-r--r-- | tests/ui/parser/suggest-remove-compount-assign-let-ice.rs | 16 | ||||
| -rw-r--r-- | tests/ui/parser/suggest-remove-compount-assign-let-ice.stderr | 26 |
3 files changed, 48 insertions, 2 deletions
diff --git a/compiler/rustc_parse/src/parser/stmt.rs b/compiler/rustc_parse/src/parser/stmt.rs index b3efb87a4a2..a3b782d651d 100644 --- a/compiler/rustc_parse/src/parser/stmt.rs +++ b/compiler/rustc_parse/src/parser/stmt.rs @@ -408,10 +408,14 @@ impl<'a> Parser<'a> { fn parse_initializer(&mut self, eq_optional: bool) -> PResult<'a, Option<P<Expr>>> { let eq_consumed = match self.token.kind { token::BinOpEq(..) => { - // Recover `let x <op>= 1` as `let x = 1` + // Recover `let x <op>= 1` as `let x = 1` We must not use `+ BytePos(1)` here + // because `<op>` can be a multi-byte lookalike that was recovered, e.g. `➖=` (the + // `➖` is a U+2796 Heavy Minus Sign Unicode Character) that was recovered as a + // `-=`. + let extra_op_span = self.psess.source_map().start_point(self.token.span); self.dcx().emit_err(errors::CompoundAssignmentExpressionInLet { span: self.token.span, - suggestion: self.token.span.with_hi(self.token.span.lo() + BytePos(1)), + suggestion: extra_op_span, }); self.bump(); true diff --git a/tests/ui/parser/suggest-remove-compount-assign-let-ice.rs b/tests/ui/parser/suggest-remove-compount-assign-let-ice.rs new file mode 100644 index 00000000000..1affee5678e --- /dev/null +++ b/tests/ui/parser/suggest-remove-compount-assign-let-ice.rs @@ -0,0 +1,16 @@ +//! Previously we would try to issue a suggestion for `let x <op>= 1`, i.e. a compound assignment +//! within a `let` binding, to remove the `<op>`. The suggestion code unfortunately incorrectly +//! assumed that the `<op>` is an exactly-1-byte ASCII character, but this assumption is incorrect +//! because we also recover Unicode-confusables like `➖=` as `-=`. In this example, the suggestion +//! code used a `+ BytePos(1)` to calculate the span of the `<op>` codepoint that looks like `-` but +//! the mult-byte Unicode look-alike would cause the suggested removal span to be inside a +//! multi-byte codepoint boundary, triggering a codepoint boundary assertion. +//! +//! issue: rust-lang/rust#128845 + +fn main() { + // Adapted from #128845 but with irrelevant components removed and simplified. + let x ➖= 1; + //~^ ERROR unknown start of token: \u{2796} + //~| ERROR: can't reassign to an uninitialized variable +} diff --git a/tests/ui/parser/suggest-remove-compount-assign-let-ice.stderr b/tests/ui/parser/suggest-remove-compount-assign-let-ice.stderr new file mode 100644 index 00000000000..59716d69b50 --- /dev/null +++ b/tests/ui/parser/suggest-remove-compount-assign-let-ice.stderr @@ -0,0 +1,26 @@ +error: unknown start of token: \u{2796} + --> $DIR/suggest-remove-compount-assign-let-ice.rs:13:11 + | +LL | let x ➖= 1; + | ^^ + | +help: Unicode character '➖' (Heavy Minus Sign) looks like '-' (Minus/Hyphen), but it is not + | +LL | let x -= 1; + | ~ + +error: can't reassign to an uninitialized variable + --> $DIR/suggest-remove-compount-assign-let-ice.rs:13:11 + | +LL | let x ➖= 1; + | ^^^ + | + = help: if you meant to overwrite, remove the `let` binding +help: initialize the variable + | +LL - let x ➖= 1; +LL + let x = 1; + | + +error: aborting due to 2 previous errors + |