12_compilerbugs.md

see here

77. Storage array with signed Integers with ABIEncoderV2:

Assigning an array of signed integers to a storage array of different type can lead to data corruption in that array.

This is due to a compiler bug introduced in v0.4.7 and fixed in v0.5.10.

78. Dynamic constructor arguments clipped with ABIEncoderV2:

A contract's constructor which takes structs or arrays that contain dynamically sized arrays reverts or decodes to invalid data when apiencoder v2 is used.

This is due to a compiler bug introduced in v0.4.16 and fixed in v0.5.9.

79. Storage array with multiSlot element with ABIEncoderV2:

Storage arrays containing structs or other statically sized arrays are not read properly when directly encoded in external function calls or in abi.encode().

This is due to a compiler bug introduced in v0.4.16 and fixed in v0.5.10.

80. Calldata structs with statically sized and dynamically encoded members with ABIEncoderV2:

Reading from calldata structs that contain dynamically encoded, but statically sized members can result in incorrect values.

This is due to a compiler bug introduced in v0.5.6 and fixed in v0.5.11.

81. Packed storage with ABIEncoderV2:

Storage structs and arrays with types shorter than 32 bytes can cause data corruption if encoded directly from storage using ABIEncoderV2.

This is due to a compiler bug introduced in v0.5.0 and fixed in v0.5.7.

82. Incorrect loads with Yul optimizer and ABIEncoderV2:

The Yul optimizer incorrectly replaces MLOAD and SLOAD calls with values that have been previously written to the load location. This can only happen if ABIEncoderV2 is activated and the experimental Yul optimizer has been activated manually in addition to the regular optimizer in the compiler settings.

This is due to a compiler bug introduced in v0.5.14 and fixed in v0.5.15.

83. Array slice dynamically encoded base type with ABIEncoderV2:

Accessing array slices of arrays with dynamically encoded base types (e.g. multi-dimensional arrays) can result in invalid data being read.

This is due to a compiler bug introduced in v0.6.0 and fixed in v0.6.8.

84. Missing escaping in formatting with ABIEncoderV2:

String literals containing double backslash characters passed directly to external or encoding function calls can lead to a different string being used when ABIEncoderV2 is enabled.

This is due to a compiler bug introduced in v0.5.14 and fixed in v0.6.8.

85. Double shift size overflow:

Double bitwise shifts by large constants whose sum overflows 256 bits can result in unexpected values. Nested logical shift operations whose total shift size is 2**256 or more are incorrectly optimized. This only applies to shifts by numbers of bits that are compile-time constant expressions. This happens when the optimizer is used and evmVersion >= Constantinople.

This is due to a compiler bug introduced in v0.5.5 and fixed in v0.5.6.

86. Incorrect byte instruction optimization:

The optimizer incorrectly handles byte opcodes whose second argument is 31 or a constant expression that evaluates to 31. This can result in unexpected values. This can happen when performing index access on bytesNN types with a compile time constant value (not index) of 31 or when using the byte opcode in inline assembly.

This is due to a compiler bug introduced in v0.5.5 and fixed in v0.5.7.

87. Essential assignments removed with Yul Optimizer :

The Yul optimizer can remove essential assignments to variables declared inside for loops when Yul's continue or break statement is used mostly while using inline assembly with for loops and continue and break statements.

This is due to a compiler bug introduced in v0.5.8/v0.6.0 and fixed in v0.5.16/v0.6.1.

88. Private methods overridden:

While private methods of base contracts are not visible and cannot be called directly from the derived contract, it is still possible to declare a function of the same name and type and thus change the behaviour of the base contract's function.

This is due to a compiler bug introduced in v0.3.0 and fixed in v0.5.17.

89. Tuple assignment multi stack slot components:

Tuple assignments with components that occupy several stack slots, i.e. nested tuples, pointers to external functions or references to dynamically sized calldata arrays, can result in invalid values.

This is due to a compiler bug introduced in v0.1.6 and fixed in v0.6.6.

90. Dynamic array cleanup:

When assigning a dynamically sized array with types of size at most 16 bytes in storage causing the assigned array to shrink, some parts of deleted slots were not zeroed out.

This is due to a compiler bug fixed in v0.7.3.

91. Empty byte array copy:

Copying an empty byte array (or string) from memory or calldata to storage can result in data corruption if the target array's length is increased subsequently without storing new data.

This is due to a compiler bug fixed in v0.7.4.

92. Memory array creation overflow:

The creation of very large memory arrays can result in overlapping memory regions and thus memory corruption.

This is due to a compiler bug introduced in v0.2.0 and fixed in v0.6.5.

93. Calldata using for:

Function calls to internal library functions with calldata parameters called via “using for” can result in invalid data being read.

This is due to a compiler bug introduced in v0.6.9 and fixed in v0.6.10.

94. Free function redefinition:

The compiler does not flag an error when two or more free functions (functions outside of a contract) with the same name and parameter types are defined in a source unit or when an imported free function alias shadows another free function with a different name but identical parameter types.

This is due to a compiler bug introduced in v0.7.1 and fixed in v0.7.2.