This example compiles on 1.35 but not 1.36 or later:
pub fn foo() -> &'static &'static bool {
{} // equivalent to {}; or ();
&&false
}(The example above was reduced from one involving match ... {...} && false, found by @digama0)
This regression was likely introduced by #60188, due to the definition of can_continue_expr_unambiguously:
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/// This operator could be used to follow a block unambiguously. |
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/// |
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/// This is used for error recovery at the moment, providing a suggestion to wrap blocks with |
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/// parentheses while having a high degree of confidence on the correctness of the suggestion. |
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pub fn can_continue_expr_unambiguously(&self) -> bool { |
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use AssocOp::*; |
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match self { |
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BitXor | // `{ 42 } ^ 3` |
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Assign | // `{ 42 } = { 42 }` |
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Divide | // `{ 42 } / 42` |
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Modulus | // `{ 42 } % 2` |
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ShiftRight | // `{ 42 } >> 2` |
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LessEqual | // `{ 42 } <= 3` |
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Greater | // `{ 42 } > 3` |
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GreaterEqual | // `{ 42 } >= 3` |
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AssignOp(_) | // `{ 42 } +=` |
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LAnd | // `{ 42 } &&foo` |
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As | // `{ 42 } as usize` |
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// Equal | // `{ 42 } == { 42 }` Accepting these here would regress incorrect |
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// NotEqual | // `{ 42 } != { 42 } struct literals parser recovery. |
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Colon => true, // `{ 42 }: usize` |
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_ => false, |
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} |
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} |
That function lists all of the operators that can't start an expression, but only continue it.
LAnd (&&) is incorrectly included, as &&expr is parsed the same as & &expr at the start of an expression.
cc @estebank
This example compiles on 1.35 but not 1.36 or later:
(The example above was reduced from one involving
match ... {...} && false, found by @digama0)This regression was likely introduced by #60188, due to the definition of
can_continue_expr_unambiguously:rust/src/librustc_ast/util/parser.rs
Lines 209 to 232 in daecab3
That function lists all of the operators that can't start an expression, but only continue it.
LAnd(&&) is incorrectly included, as&&expris parsed the same as& &exprat the start of an expression.cc @estebank