Fix several trivial problems found by clang 7's scan-build #2205
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Left shift of negative numbers is undefined in the "C" standard. Multiplying by 256 has the intended effect (in the absence of integer overflow, anyway), can be implemented using the same shift instruction, but does not invoke undefined behavior. This problem was found using clang 7's scan-build static analyzer.
The remaining assignment was added in upstream micropython; the deleted assignment was added in circuitpython as part of the long-lived object area feature. During the merge, the redundant assignment was not removed. (since collected is a local variable and no pointers to it escape, it doesn't seem possible for the placement of the assignment before or after GC_ENTER() is important) This diagnostic was found by clang 7's scan-build static analyzer.
Left shift of negative numbers is undefined in the "C" standard. Multiplying by 128 has the intended effect (in the absence of integer overflow, anyway), can be implemented using the same shift instruction, but does not invoke undefined behavior. This problem was found using clang 7's scan-build static analyzer.
If kw_args is NULL then memcpy() gets a NULL source argument. This is undefined behavior under the C standard, even if 0 bytes are being copied. This problem was found using clang 7's scan-build static analyzer.
tannewt
reviewed
Oct 8, 2019
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By invoking
scan-build makeinports/unix, a number of diagnostics are found. This fixes several of the trivial ones.