Bug 14831 – Each function local symbols should have unique mangled name

Typical example: module test; void main() { { int x; pragma(msg, x.mangleof); } // _D4test4mainFZ1xi { int x; pragma(msg, x.mangleof); } // _D4test4mainFZ1xi } Even if two or more different function local symbols have same name, their mangled name should be unique. --- Currently the mangling issue causes many pragmatic problems. https://issues.dlang.org/show_bug.cgi?id=10619 If the same name symbols are captured by TemplateAliasParameter, the corresponding template instances will be entangled. https://issues.dlang.org/show_bug.cgi?id=14820 If the symbols declared in unrolled loop (compile-time iterated foreach) statement, they're easily entangled. https://issues.dlang.org/show_bug.cgi?id=9748 The problem is not only for variables, but also function local templates and template functions. --- Currently function local functions, type definitions, and static variables are not allowed. module test; void main() { { void f() {} pragma(msg, f.mangleof); } { void f() {} pragma(msg, f.mangleof); } // error { struct S {} pragma(msg, S.mangleof); } { struct S {} pragma(msg, S.mangleof); } // ICE { class C {} pragma(msg, C.mangleof); } { class C {} pragma(msg, C.mangleof); } // ICE { enum E { a } pragma(msg, E.mangleof); } { enum E { a } pragma(msg, E.mangleof); } // error { static int v = 0; pragma(msg, v.mangleof); } { static int v = 1; pragma(msg, v.mangleof); } // error } However, I think the rejections are not so meaningful. I cannot see any reason to limit such the static function local symbols to unique.

(In reply to Kenji Hara from comment #0) > Currently function local functions, type definitions, and static variables > are not allowed. > [snip] > > However, I think the rejections are not so meaningful. I cannot see any > reason to limit such the static function local symbols to unique. I'll separate that suggestion into the issue 3031

*** Issue 10619 has been marked as a duplicate of this issue. ***

*** Issue 14820 has been marked as a duplicate of this issue. ***

*** Issue 9748 has been marked as a duplicate of this issue. ***

*** Issue 16608 has been marked as a duplicate of this issue. ***

A bounty has been set on this issue: https://www.flipcause.com/secure/cause_pdetails/NjI2NjY=

Test case compiles and reports unique manglings. Tested with DMD64 D Compiler v2.095.1-beta.1-171-gdf3c9e093

Test case still produces two identical manglings on DMD git master (7a0382177f35b2766c2d0ba60dae5e541d8033e0): Output of OP's test case: ------- _D4test4mainFZ1xi _D4test4mainFZ1xi ------- This is wrong because `x` in each case refers to a different local variable in a different scope.

Furthermore, all the test cases posted in issue #10619 still fail on DMD git master.

(In reply to hsteoh from comment #9) > Test case still produces two identical manglings on DMD git master > (7a0382177f35b2766c2d0ba60dae5e541d8033e0): Sorry, missed the first example.

@MoonlightSentinel updated dlang/dmd pull request #12235 "Fix 14831 - Each function local symbols should have unique mangled name" fixing this issue: - Fix 14831 - Each function local symbols should have unique mangled name PR #12119 already fixed collisions for several declarations but missed local variables. The check for `isDataSeg` was a remnant of the old error raised for `static`/`__gshared` variables. Removing it enables the mangling fixup for local variables. Note that this doesn't fix https://issues.dlang.org/show_bug.cgi?id=10619 which is unrelated to the mangling. https://github.com/dlang/dmd/pull/12235

dlang/dmd pull request #12235 "Fix 14831 - Each function local symbols should have unique mangled name" was merged into stable: - 1d2b5ec75d3bad4f33ccacdf5fe4913d2b512a47 by MoonlightSentinel: Fix 14831 - Each function local symbols should have unique mangled name PR #12119 already fixed collisions for several declarations but missed local variables. The check for `isDataSeg` was a remnant of the old error raised for `static`/`__gshared` variables. Removing it enables the mangling fixup for local variables. Note that this doesn't fix https://issues.dlang.org/show_bug.cgi?id=10619 which is unrelated to the mangling. https://github.com/dlang/dmd/pull/12235

dlang/dmd pull request #12253 "merge stable" was merged into master: - 8b653c5629b930fe8bf956b4be109781f67cb59a by MoonlightSentinel: Fix 14831 - Each function local symbols should have unique mangled name PR #12119 already fixed collisions for several declarations but missed local variables. The check for `isDataSeg` was a remnant of the old error raised for `static`/`__gshared` variables. Removing it enables the mangling fixup for local variables. Note that this doesn't fix https://issues.dlang.org/show_bug.cgi?id=10619 which is unrelated to the mangling. https://github.com/dlang/dmd/pull/12253

*** Issue 19674 has been marked as a duplicate of this issue. ***