macros: fix span of body variable #5244
Merged
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Motivation
Fixes #5243
Solution
This is basically the same problem as dtolnay/async-trait#104 and dtolnay/async-trait#46, and can be fixed by assigning a consistent span to the same variable. See also dtolnay/async-trait#105 (comment). (The root cause is a compiler bug that overwrites spans of non-
:tt
metavariables during declarative macro expansion.)