0x8000-0000 marked an inline comment as done.
0x8000-0000 added inline comments.
================
Comment at: clang-tools-extra/clang-tidy/readability/MagicNumbersCheck.cpp:129
+ // expanded class enumeration value.
+ if (Parent.get<CStyleCastExpr>())
+ return true;
----------------
0x8000-0000 wrote:
> aaron.ballman wrote:
> > So will this no longer treat *any* C-style cast as being a magic number?
> > e.g., `int i; i = (int)12;`
> Sadly, it would seem so.
>
> if (ValueArray[(int)4] > ValueArray[1]) produces the following AST:
>
> ```
> | | | | `-ArraySubscriptExpr 0x11545f0 <col:7, col:24> 'int' lvalue
> | | | | |-ImplicitCastExpr 0x11545d8 <col:7> 'int *' <ArrayToPointerDecay>
> | | | | | `-DeclRefExpr 0x1154558 <col:7> 'int [5]' lvalue Var 0x1153cb0
> 'ValueArray' 'int [5]'
>
> | | | | `-CStyleCastExpr 0x11545b0 <col:18, col:23> 'int' <NoOp>
> | | | | `-IntegerLiteral 0x1154578 <col:23> 'int' 4
> ```
>
> While the test case we're trying to avoid is:
> ```
> `-TemplateSpecializationType 0x1169ee0 'holder<(Letter)9U>' sugar holder
> |-TemplateArgument expr
> | `-ConstantExpr 0x1169dc0 <col:59> 'Letter' 9
> | `-SubstNonTypeTemplateParmExpr 0x1169da0 <col:59> 'Letter'
> | `-CStyleCastExpr 0x1169d78 <col:59> 'Letter' <IntegralCast>
> | `-IntegerLiteral 0x1169d48 <col:59> 'unsigned int' 9
> `-RecordType 0x1169ec0 'holder<Letter::J>'
> `-ClassTemplateSpecialization 0x1169de0 'holder'
> ```
>
> Now, the question is - do we care? How many people use a C cast with a bare
> integer?
>
> I suppose I can add a check for the grandparent node to be
> SubstNonTypeTemplateParmExpr, in order to filter this out?
An interesting fact is that the C-style cast does not produce a warning now
anyway (even before applying this change.) and I don't have any idea why.
Adding these lines does not create a test failure:
```
+ 79 if (((int)4) > IntSquarer[10])
+ 80 return 0;
```
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D71686/new/
https://reviews.llvm.org/D71686
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