Support suppressing opportunistic compiler warnings #4598
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lib/compiler/doc/src/compile.xml
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| disabling all warnings).</p> | ||
| <p>Another kind of warnings is <em>opportunistic | ||
| warnings</em>. They are generated when the compiler | ||
| <strong>happens</strong> to notice potential issues during |
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Should this stress "potential" and not "happens"? Or is it not a given that in some cases e.g. unused returned values would be missed by the compiler?
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I wanted to emphasize the other kind of problem with opportunistic warnings, namely that not all potential problems are reported. I think it is better to remove the emphasis on "happens".
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Classify the warnings from the v3_core, sys_core_fold, and
v3_kernel into three different categories:
* {nomatch,Term} - a pattern will not match for some reason.
* {failed,Term} - an expression or term construction will fail for some reason.
* {ignored,Term} - an expression or constructed term is ignored.
The classification will make it easier to selectively disable certain
categories of warnings.
It has never been possible to disable the opportunistic warnings generated by the code generation and optimization passes. It is high time to allow the user to disable those warnings, especially since using funs to suppress warnings may no longer work since commit 72675ba that introduced inlining of funs that were immediately used.
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michaelklishin
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To work around erlang-lager/lager#546. The flag was introduced in erlang/otp#4598, which is more recent than 24-rc.1.
michaelklishin
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To work around erlang-lager/lager#546. The flag was introduced in erlang/otp#4598, which is more recent than 24-rc.1.
michaelklishin
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To work around erlang-lager/lager#546. The flag was introduced in erlang/otp#4598, which is more recent than 24-rc.1.
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Opportunistic warnings are the warnings that the compiler's optimization and code generating passes emit when they happen to notice potential issues.
One problem with the opportunistic warnings is that there can be inappropriate warnings for perfectly good code, especially if inlining or macros are involved. Therefore, it has been our TO DO list for a long time to implement a way to turn off those warnings.
#4545, which was recently merged, can cause more spurious warnings to appear (because a
funthat is now inlined could suppress warnings intentionally or unintentionally). Therefore, it's high time to add options to suppress opportunistic warnings.