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July 11, 2018 Multiple functions, same signature | ||||
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I was surprised to find out today that this compiles: void foo() {} void foo() {} void main() {} Is it a bug, or just a weird design decision? "alphaglosined" on IRC seemed to think it was a regression. Please confirm, so that I can file a bug, or understand the design decision rationale. |
July 11, 2018 Re: Multiple functions, same signature | ||||
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Posted in reply to Luís Marques | On Wednesday, 11 July 2018 at 15:58:05 UTC, Luís Marques wrote: > I was surprised to find out today that this compiles: > > void foo() {} > void foo() {} > void main() {} > > Is it a bug, or just a weird design decision? "alphaglosined" on IRC seemed to think it was a regression. Please confirm, so that I can file a bug, or understand the design decision rationale. Definitely a change, but it always compiled, it just used to fail to link https://run.dlang.io/is/b0JxD9 |
July 12, 2018 Re: Multiple functions, same signature | ||||
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Posted in reply to Luís Marques | On 12/07/2018 3:58 AM, Luís Marques wrote: > I was surprised to find out today that this compiles: > > void foo() {} > void foo() {} > void main() {} > > Is it a bug, or just a weird design decision? "alphaglosined" on IRC seemed to think it was a regression. Please confirm, so that I can file a bug, or understand the design decision rationale. The reason I think that it is a regression is because of [0]. Either the change log didn't include some changes, environment/linker or its a regression IMHO. ``` Up to 2.071.2: Failure with output: ----- onlineapp.o: In function `_D9onlineapp3fooFiZv': /sandbox/onlineapp.d:2: multiple definition of `_D9onlineapp3fooFiZv' onlineapp.o:onlineapp.d:(.text._D9onlineapp3fooFiZv+0x0): first defined here collect2: error: ld returned 1 exit status --- errorlevel 1 ----- 2.072.2 to 2.074.1: Failure with output: ----- onlineapp.o: In function `_D9onlineapp3fooFiZv': /sandbox/onlineapp.d:2: multiple definition of `_D9onlineapp3fooFiZv' onlineapp.o:onlineapp.d:(.text._D9onlineapp3fooFiZv+0x0): first defined here collect2: error: ld returned 1 exit status Error: linker exited with status 1 ----- Since 2.075.1: Success and no output ``` [0] https://run.dlang.io/is/AGuM6P |
July 11, 2018 Re: Multiple functions, same signature | ||||
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Posted in reply to John Colvin | On Wednesday, 11 July 2018 at 16:01:48 UTC, John Colvin wrote:
> On Wednesday, 11 July 2018 at 15:58:05 UTC, Luís Marques wrote:
> Definitely a change, but it always compiled, it just used to fail to link
Do you know why the frontend doesn't complain about a redefinition, like C++ does?
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July 11, 2018 Re: Multiple functions, same signature | ||||
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Posted in reply to Luís Marques | On 2018-07-11 17:58, Luís Marques wrote: > I was surprised to find out today that this compiles: > > void foo() {} > void foo() {} > void main() {} > > Is it a bug, or just a weird design decision? "alphaglosined" on IRC seemed to think it was a regression. Please confirm, so that I can file a bug, or understand the design decision rationale. You'll get an error if you call "foo". -- /Jacob Carlborg |
July 11, 2018 Re: Multiple functions, same signature | ||||
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Posted in reply to Jacob Carlborg | On Wednesday, 11 July 2018 at 16:21:26 UTC, Jacob Carlborg wrote:
> You'll get an error if you call "foo".
I understand that. Still seems like something that the frontend should detect, unless there's a good use case for multiple (re)definitions. If I had to guess, it's probably to support generic code which may have the same or different type modifiers applied, possibly resulting in a collision.
In my specific case, due to the functions being manipulated by generic code, it led to a harder to diagnose bug, since the functions weren't called directly (or at all, of course). Instead, the openmethods library builds a list of dispatch targets, but it didn't detect at compile-time that the targets were redundant, which led to a *runtime* error, and a harder to diagnose situation. openmethods.d could be changed to deal with that, but it seems like the frontend would be the ideal place to check it, unless D should really support redundant functions.
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July 11, 2018 Re: Multiple functions, same signature | ||||
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Posted in reply to Luís Marques | On Wednesday, 11 July 2018 at 15:58:05 UTC, Luís Marques wrote: > I was surprised to find out today that this compiles: > > void foo() {} > void foo() {} > void main() {} > > Is it a bug, or just a weird design decision? "alphaglosined" on IRC seemed to think it was a regression. Please confirm, so that I can file a bug, or understand the design decision rationale. This will be deprecated soon: https://github.com/dlang/dmd/pull/8429 |
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