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+### What it does
+Checks for usage of unconstrained numeric literals which may cause default numeric fallback in type
+inference.
+
+Default numeric fallback means that if numeric types have not yet been bound to concrete
+types at the end of type inference, then integer type is bound to `i32`, and similarly
+floating type is bound to `f64`.
+
+See [RFC0212](https://github.com/rust-lang/rfcs/blob/master/text/0212-restore-int-fallback.md) for more information about the fallback.
+
+### Why is this bad?
+For those who are very careful about types, default numeric fallback
+can be a pitfall that cause unexpected runtime behavior.
+
+### Known problems
+This lint can only be allowed at the function level or above.
+
+### Example
+```
+let i = 10;
+let f = 1.23;
+```
+
+Use instead:
+```
+let i = 10i32;
+let f = 1.23f64;
+```
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