Don't produce debug information for compiler-introduced-vars when desugaring assignments. #138818
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…ugaring assignments.
An assignment such as
(a, b) = (b, c);
desugars to the HIR
{ let (lhs, lhs) = (b, c); a = lhs; b = lhs; };
The repeated `lhs` leads to multiple Locals assigned to the same DILocalVariable. Rather than
attempting to fix that, get rid of the debug info for these bindings that don't even exist
in the program to begin with.
Fixes rust-lang#138198
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Some changes occurred in match lowering cc @Nadrieril |
jieyouxu
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Mar 23, 2025
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@bors r+ |
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Comment on lines
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| // For now we only recognize the output of desugaring assigns. | ||
| if name != sym::lhs { | ||
| return true; | ||
| } |
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I do wonder if we are synthesizing other constructs that are not present in the surface syntax that may also need to skip debuginfo generation, but I can't immediately think of other cases. If they crop up, well this (or next to it) is a good place to centralize the handling.
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An assignment such as
(a, b) = (b, c);
desugars to the HIR
{ let (lhs, lhs) = (b, c); a = lhs; b = lhs; };
The repeated
lhsleads to multiple Locals assigned to the same DILocalVariable. Rather than attempting to fix that, get rid of the debug info for these bindings that don't even exist in the program to begin with.Fixes #138198
r? @jieyouxu