rust/tests/ui/btreemap/btreemap-index-mut-2.stderr

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error[E0594]: cannot assign to data in an index of `BTreeMap<u32, u32>`
--> $DIR/btreemap-index-mut-2.rs:6:9
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LL | map[&0] = 1;
| ^^^^^^^^^^^ cannot assign
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= help: trait `IndexMut` is required to modify indexed content, but it is not implemented for `BTreeMap<u32, u32>`
help: use `.insert()` to insert a value into a `BTreeMap<u32, u32>`, `.get_mut()` to modify it, or the entry API for more flexibility
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LL - map[&0] = 1;
LL + map.insert(&0, 1);
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LL - map[&0] = 1;
LL + if let Some(val) = map.get_mut(&0) { *val = 1; };
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LL - map[&0] = 1;
LL + let val = map.entry(&0).or_insert(1);
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error: aborting due to 1 previous error
For more information about this error, try `rustc --explain E0594`.