{"header":{"message":"Fill in some explanations of unsafe code\n\nCloses #14.\n","description":null,"timestamp":"2019-11-17T23:24:35Z","authors":[{"email":"dtolnay@gmail.com","name":"David Tolnay"}]},"hash":"A7XDW47SJ3ZYWRH64PLNI77XZTVX5FY6NX2LMT33L6BMUH3DYBMQC","authors":[],"deps":{"hashes":[["A7XDW47SJ3ZYWRH64PLNI77XZTVX5FY6NX2LMT33L6BMUH3DYBMQC","Fill in some explanations of unsafe code\n\nCloses #14.\n"],["AA",null],["R56UTEJ4GIAYX5WC4MCQQBRAFLMNIIV4ZCUNDQMFJGONE74H2BSQC","Ptr read only needs a const ptr\n"],["ZEYYSYM7QBZG4Q67AN3CHYZQWO2DVVHXRAK6NX44UQD6VO3JTK3AC","Rename the ErrorImpl tail to _object\n\nAvoids _error.error repetition when manipulation ErrorImpl,\nand works well with object_ref / object_mut naming in the vtable.\n"],["YNTEYSW7NVBWQLJU45XRK7AWQR5NWFOB4UUVVQ62ERZOO2QJJGAAC","Move error formatting to fmt.rs\n"],["CITEDKPB6MKVZUEYEDE5ZKTNVY35HCOAXKDPYG7YLLEOVFNMSRXQC","Import implementation from fehler 1.0.0-alpha.1\n"],["LX7EZ6TKJCQI3K7SV56WMTPFY672WN5UOBGXKKXQI7S73GMWNNXAC","Change Error::construct to unsafe fn because TypeId must be correct\n"],["NPOFDGQF4CE72IZBT5Y7KPIBHWPPNOEPBYD5RTUHSVUJ2W4XFRVQC","Deallocate ErrorImpl with the right Layout\n"],["VWTWVVRECX62JABUZYFCTCPWTXXT3DB4635RIAGCKIQMGJ7VXRGAC","Move downcasting into vtable\n"],["Z4YYQXEE4OQPF22I4LD7RVQIBKK67AHCYR6C35MANUCIC4P3EPYQC","Deallocate with the right Layout during downcast\n"],["W5YRNIBZIMTQLOKIBWBF7CHCIOLKXVHV7Y2AIKMKG7GCQSAVZKBAC","Support downcasting ContextError to C and E\n"],["T64LKJ2RTUDFYSJQI7KF4WHZYXZHNEGNOS7ZMMCRIQZ4YN5LOOMAC","Fix potential UB by removing reliance on trait object layout\n\nAdds a raw vtable object (similar to `RawWakerVTable`) that is manually\ncreated and has methods to dynamically cast to `dyn StdError`.\n"],["CZP5PD5NYLDULLW43VOL6V75CH6DDEJO7H6JSGQSIV2WNSQF4A6QC","Rename vtable object ref and mut methods that are no longer raw ptr\n"],["RIKD63GT7RFV3UAV4BYD57GFXKXALWUP6J7AAHB3M6JVAZ3WFTXAC","Add conversion from Error to Box\n"],["LR3QQRO4ZFYYIY4JJ7LJIO4VUK3EWESPIAPLPPIP4W7N75PSVQHQC","Support downcasting ContextError to C and cause\n"],["DFDCD3LPJCYCNINXBXGFAYD4CT2SBI4RBITE7OK5D5QPTIWWMQKAC","Fill in StdError methods for ErrorImpl\n"]],"deps":["R56UTEJ4GIAYX5WC4MCQQBRAFLMNIIV4ZCUNDQMFJGONE74H2BSQC","ZEYYSYM7QBZG4Q67AN3CHYZQWO2DVVHXRAK6NX44UQD6VO3JTK3AC","YNTEYSW7NVBWQLJU45XRK7AWQR5NWFOB4UUVVQ62ERZOO2QJJGAAC"],"known":[]},"hunks":[{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":164,"atom":{"NewVertex":{"up_context":[{"change":7,"pos":972}],"down_context":[{"change":8,"pos":127}],"flag":"BLOCK","start":0,"end":458,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":" // Erase the concrete type of E from the compile-time type system. This"},{"Add":" // is equivalent to the safe unsize coersion from Box> to"},{"Add":" // Box> except that the"},{"Add":" // result is a thin pointer. The necessary behavior for manipulating the"},{"Add":" // underlying ErrorImpl is preserved in the vtable provided by the"},{"Add":" // caller rather than a builtin fat pointer vtable."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":331,"atom":{"NewVertex":{"up_context":[{"change":9,"pos":387}],"down_context":[{"change":9,"pos":387}],"flag":"BLOCK","start":459,"end":591,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":" // Use vtable to find NonNull<()> which points to a value of type E"},{"Add":" // somewhere inside the data structure."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":337,"atom":{"NewVertex":{"up_context":[{"change":9,"pos":568}],"down_context":[{"change":10,"pos":84}],"flag":"BLOCK","start":592,"end":747,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":""},{"Add":" // Prepare to read E out of the data structure. We'll drop the rest"},{"Add":" // of the data structure separately so that E is not dropped."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":341,"atom":{"NewVertex":{"up_context":[{"change":10,"pos":133}],"down_context":[{"change":9,"pos":569}],"flag":"BLOCK","start":748,"end":803,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":""},{"Add":" // Read E from where the vtable found it."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":344,"atom":{"NewVertex":{"up_context":[{"change":9,"pos":631}],"down_context":[{"change":9,"pos":631}],"flag":"BLOCK","start":804,"end":944,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":""},{"Add":" // Read Box> from self. Can't move it out because"},{"Add":" // Error has a Drop impl which we want to not run."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":349,"atom":{"NewVertex":{"up_context":[{"change":9,"pos":738}],"down_context":[{"change":11,"pos":397}],"flag":"BLOCK","start":945,"end":1007,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":""},{"Add":" // Drop rest of the data structure outside of E."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":352,"atom":{"NewVertex":{"up_context":[{"change":11,"pos":459}],"down_context":[{"change":9,"pos":793}],"flag":"BLOCK","start":1008,"end":1009,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":""}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":399,"atom":{"NewVertex":{"up_context":[{"change":9,"pos":873}],"down_context":[{"change":9,"pos":873}],"flag":"BLOCK","start":1010,"end":1142,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":" // Use vtable to find NonNull<()> which points to a value of type E"},{"Add":" // somewhere inside the data structure."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":413,"atom":{"NewVertex":{"up_context":[{"change":9,"pos":1059}],"down_context":[{"change":9,"pos":1059}],"flag":"BLOCK","start":1143,"end":1275,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":" // Use vtable to find NonNull<()> which points to a value of type E"},{"Add":" // somewhere inside the data structure."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":460,"atom":{"NewVertex":{"up_context":[{"change":8,"pos":301}],"down_context":[{"change":2,"pos":0}],"flag":"BLOCK","start":1276,"end":1326,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":" // Read Box> from self."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":463,"atom":{"NewVertex":{"up_context":[{"change":8,"pos":411}],"down_context":[{"change":8,"pos":411}],"flag":"BLOCK","start":1327,"end":1378,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":""},{"Add":" // Invoke the vtable's drop behavior."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":479,"atom":{"NewVertex":{"up_context":[{"change":8,"pos":523}],"down_context":[{"change":8,"pos":523}],"flag":"BLOCK","start":1379,"end":1435,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":"// Safety: requires layout of *e to match ErrorImpl."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":487,"atom":{"NewVertex":{"up_context":[{"change":10,"pos":471}],"down_context":[{"change":11,"pos":522}],"flag":"BLOCK","start":1436,"end":1492,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":"// Safety: requires layout of *e to match ErrorImpl."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":497,"atom":{"NewVertex":{"up_context":[{"change":12,"pos":364}],"down_context":[{"change":13,"pos":264}],"flag":"BLOCK","start":1493,"end":1549,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":"// Safety: requires layout of *e to match ErrorImpl."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":502,"atom":{"NewVertex":{"up_context":[{"change":12,"pos":500}],"down_context":[{"change":3,"pos":29}],"flag":"BLOCK","start":1550,"end":1623,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":" // Attach E's native StdError vtable onto a pointer to self._object."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":506,"atom":{"NewVertex":{"up_context":[{"change":6,"pos":9177}],"down_context":[{"change":13,"pos":351}],"flag":"BLOCK","start":1624,"end":1680,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":"// Safety: requires layout of *e to match ErrorImpl."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":511,"atom":{"NewVertex":{"up_context":[{"change":12,"pos":655}],"down_context":[{"change":3,"pos":97}],"flag":"BLOCK","start":1681,"end":1754,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":" // Attach E's native StdError vtable onto a pointer to self._object."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":515,"atom":{"NewVertex":{"up_context":[{"change":14,"pos":308}],"down_context":[{"change":14,"pos":308}],"flag":"BLOCK","start":1755,"end":1811,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":"// Safety: requires layout of *e to match ErrorImpl."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":520,"atom":{"NewVertex":{"up_context":[{"change":14,"pos":451}],"down_context":[{"change":14,"pos":451}],"flag":"BLOCK","start":1812,"end":1893,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":" // Attach ErrorImpl's native StdError vtable. The StdError impl is below."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":524,"atom":{"NewVertex":{"up_context":[{"change":9,"pos":1378}],"down_context":[{"change":9,"pos":1378}],"flag":"BLOCK","start":1894,"end":1950,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":"// Safety: requires layout of *e to match ErrorImpl."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":530,"atom":{"NewVertex":{"up_context":[{"change":9,"pos":1520}],"down_context":[{"change":9,"pos":1520}],"flag":"BLOCK","start":1951,"end":2062,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":" // Caller is looking for an E pointer and e is ErrorImpl, take a"},{"Add":" // pointer to its E field."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":540,"atom":{"NewVertex":{"up_context":[{"change":11,"pos":619}],"down_context":[{"change":11,"pos":774}],"flag":"BLOCK","start":2063,"end":2136,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":"// Safety: requires layout of *e to match ErrorImpl>."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":559,"atom":{"NewVertex":{"up_context":[{"change":11,"pos":1427}],"down_context":[{"change":11,"pos":1427}],"flag":"BLOCK","start":2137,"end":2210,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":"// Safety: requires layout of *e to match ErrorImpl>."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":582,"atom":{"NewVertex":{"up_context":[{"change":15,"pos":512}],"down_context":[{"change":15,"pos":886}],"flag":"BLOCK","start":2211,"end":2288,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":"// Safety: requires layout of *e to match ErrorImpl>."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":592,"atom":{"NewVertex":{"up_context":[{"change":15,"pos":1262}],"down_context":[{"change":15,"pos":1262}],"flag":"BLOCK","start":2289,"end":2361,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":" // Recurse down the context chain per the inner error's vtable."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":599,"atom":{"NewVertex":{"up_context":[{"change":15,"pos":1482}],"down_context":[{"change":15,"pos":1482}],"flag":"BLOCK","start":2362,"end":2439,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":"// Safety: requires layout of *e to match ErrorImpl>."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":611,"atom":{"NewVertex":{"up_context":[{"change":11,"pos":2040}],"down_context":[{"change":11,"pos":2040}],"flag":"BLOCK","start":2440,"end":2520,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":" // Drop the entire rest of the data structure rooted in the next Error."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":618,"atom":{"NewVertex":{"up_context":[{"change":15,"pos":2065}],"down_context":[{"change":3,"pos":547}],"flag":"BLOCK","start":2521,"end":2597,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":" // Read out a ManuallyDrop>> from the next error."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":622,"atom":{"NewVertex":{"up_context":[{"change":15,"pos":2204}],"down_context":[{"change":15,"pos":2204}],"flag":"BLOCK","start":2598,"end":2671,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":" // Recursively drop the next error using the same target typeid."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":693,"atom":{"NewVertex":{"up_context":[{"change":16,"pos":64}],"down_context":[{"change":16,"pos":64}],"flag":"BLOCK","start":2672,"end":2859,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":" // Erase the concrete type of E but preserve the vtable in self.vtable"},{"Add":" // for manipulating the resulting thin pointer. This is analogous to an"},{"Add":" // unsize coersion."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":702,"atom":{"NewVertex":{"up_context":[{"change":4,"pos":76}],"down_context":[{"change":13,"pos":446}],"flag":"BLOCK","start":2860,"end":2961,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":" // Use vtable to attach E's native StdError vtable for the right"},{"Add":" // original type E."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":708,"atom":{"NewVertex":{"up_context":[{"change":4,"pos":165}],"down_context":[{"change":13,"pos":499}],"flag":"BLOCK","start":2962,"end":3063,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":" // Use vtable to attach E's native StdError vtable for the right"},{"Add":" // original type E."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":769,"atom":{"NewVertex":{"up_context":[{"change":14,"pos":2807}],"down_context":[{"change":14,"pos":2807}],"flag":"BLOCK","start":3064,"end":3204,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":" // Read Box> from error. Can't move it out because"},{"Add":" // Error has a Drop impl which we want to not run."}]}},{"Edit":{"inode":{"change":6,"pos":3238},"path":"src/error.rs","line":773,"atom":{"NewVertex":{"up_context":[{"change":14,"pos":2914}],"down_context":[{"change":14,"pos":2914}],"flag":"BLOCK","start":3205,"end":3326,"inode":{"change":6,"pos":3238}}},"contents":[{"Add":""},{"Add":" // Use vtable to attach ErrorImpl's native StdError vtable for"},{"Add":" // the right original type E."}]}}],"owner":"yaahc","repo":"eyre","token":"lq48/uSrnM9SCjicfdr5/hcCBY/lNm0kd4OwYI1FGcU=","login":null}

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