digitalmars.D.bugs - [Issue 23229] New: struct used as UDA with opDispatch errors with
- d-bugmail puremagic.com (45/45) Jul 04 2022 https://issues.dlang.org/show_bug.cgi?id=23229
https://issues.dlang.org/show_bug.cgi?id=23229 Issue ID: 23229 Summary: struct used as UDA with opDispatch errors with "variable `impl` cannot be modified at compile time" if it includes a call to writeln Product: D Version: D2 Hardware: x86_64 OS: Linux Status: NEW Severity: normal Priority: P1 Component: dmd Assignee: nobody puremagic.com Reporter: zorael gmail.com Manjaro/Arch x86_64, dmd v2.100.0, ldc 1.29.0. A struct used as a UDA fails to compile if it has an `opDispatch` which invokes writeln. --- import std.stdio; struct UDA { string _hello; void opDispatch(string var, T)(T value) { writeln("opDispatch ", var); enum realVar = '_' ~ var; mixin(realVar) = value; } } (UDA() .hello("hi") ) struct Foo {} void main() {} --- /dlang/dmd/linux/bin64/../../src/phobos/std/stdio.d(5190): Error: variable `impl` cannot be modified at compile time /dlang/dmd/linux/bin64/../../src/phobos/std/stdio.d(4130): called from here: `makeGlobal()` /dlang/dmd/linux/bin64/../../src/phobos/std/stdio.d(4235): called from here: `trustedStdout()` onlineapp.d(9): called from here: `writeln("opDispatch ", "hello")` onlineapp.d(16): called from here: `UDA(null).opDispatch("hi")` --
Jul 04 2022