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Bug in comptime function memoization? #639

thejoshwolfe opened this Issue Dec 2, 2017 · 0 comments


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thejoshwolfe commented Dec 2, 2017

I haven't pinned down exactly what's going wrong here, but I think it's a bug in logic that the comptime evaluator uses to determine if a function call can be skipped because it's identical to the last time we called the function.

On commit 67b8b00 :

~/dev/zig/build$ ./zig test ../std/sort.zig
/home/josh/dev/zig/std/debug.zig:55:13: error: unable to evaluate constant expression
            @panic("assertion failure")
/home/josh/dev/zig/std/sort.zig:118:19: note: called from here
            assert(item.value == expected[i].value);
/home/josh/dev/zig/std/sort.zig:76:28: note: called from here
    comptime testStableSort();

By throwing @compileLog()s all over the place, my best guess is that sort_stable() is only really getting called for the first case, not the second.

@thejoshwolfe thejoshwolfe added the bug label Dec 2, 2017

@thejoshwolfe thejoshwolfe reopened this Dec 2, 2017

@andrewrk andrewrk added this to the 0.2.0 milestone Dec 3, 2017

@andrewrk andrewrk closed this in 6db9be8 Mar 9, 2018

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