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Tests/Docs after stricter explicit conversion.

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hrkrshnn
2020-12-03 16:51:05 +01:00
committed by chriseth
parent 92ab32e532
commit 40244c5469
25 changed files with 183 additions and 64 deletions
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docs/080-breaking-changes.rst
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@@ -49,6 +49,26 @@ New Restrictions
3. Explicit conversions between literals and enums are only allowed if the literal can
represent a value in the enum.
* There are new restrictions on explicit conversions between two different types. The conversion is
only allowed when there is at most one change in sign, width or 'kind' / different type (``int``,
``address``, ``bytesNN``, etc.) For example, the conversion ``uint16(int8)`` is disallowed since
the conversion changes width (8 bits to 16 bits) and sign (signed integer to unsigned integer.) To
get the previous behaviour, use an intermediate conversion. In the previous example, this would be
``uint16(uint8(int8))`` or ``uint16(int16(int8))``. The following are some examples of conversions
that are disallowed by this rule. Note that, given types ``T`` and ``S``, the notation ``T(S)``
refers to the explicit conversion ``T(x)``, where ``x`` is any arbitrary variable of type ``S``.
- ``address(uint)`` and ``uint(address)``: converting both 'kind' and width. Replace this by
``address(uint160(uint))`` and ``uint(uint160(address))`` respectively.
- ``int80(bytes10)`` and ``bytes10(int80)``: converting both 'kind' and sign. Replace this by
``int80(uint80(bytes10))`` and ``bytes10(uint80(int80)`` respectively.
- ``Contract(uint)``: converting 'kind' and width. Replace this by
``Contract(address(uint160(uint)))``.
These conversions were disallowed since there was ambiguity in such conversions. For example, in
the expression ``uint16 x = uint16(int8(-1))``, the value of ``x`` would depend on whether the sign or
the width conversion was applied first.
* Function call options can only be given once, i.e. ``c.f{gas: 10000}{value: 1}()`` is invalid and has to be changed to ``c.f{gas: 10000, value: 1}()``.
* The global functions ``log0``, ``log1``, ``log2``, ``log3`` and ``log4`` have been removed.