Bug 23509 – ImportC: need statement expressions extension for GLibC's assert()

Just tried building the Mosquitto MQTT library (specifically just the client library) on Artix Linux x64 solely with DMD master. I tried the following: cd lib dmd-master -P=-I../ -P=-I../deps *.c ...and got some errors on every mention of assert(). Try just one file to see what I mean: dmd-master -P=-I../ -P=-I../deps messages_mosq.c messages_mosq.c(52): Error: expression expected, not `{` messages_mosq.c(52): Error: found `if` when expecting `)` messages_mosq.c(52): Error: found `;` when expecting `)` messages_mosq.c(52): Error: found `else` when expecting `;` following statement messages_mosq.c(52): Error: no type for declarator before `)` messages_mosq.c(54): Error: no type for declarator before `for` messages_mosq.c(54): Error: no type for declarator before `(` messages_mosq.c(54): Error: no type for declarator before `(` messages_mosq.c(56): Error: no type-specifier for declarator messages_mosq.c(56): Error: found `;` when expecting `)` messages_mosq.c(57): Error: `=`, `;` or `,` expected to end declaration instead of `}` messages_mosq.c(58): Error: no type for declarator before `(` messages_mosq.c(58): Error: no type for declarator before `(` messages_mosq.c(60): Error: no type-specifier for declarator messages_mosq.c(60): Error: found `;` when expecting `)` messages_mosq.c(61): Error: `=`, `;` or `,` expected to end declaration instead of `}` messages_mosq.c(68): Error: no type-specifier for declarator messages_mosq.c(69): Error: no type-specifier for declarator messages_mosq.c(70): Error: no type for declarator before `if` messages_mosq.c(71): Error: no type-specifier for declarator If I comment out all uses of assert() (including in deps/utlist.h), I get similar errors from the use of the DL_DELETE macro in deps/utlist.h: messages_mosq.c(154): Error: found `else` when expecting `while` messages_mosq.c(154): Error: found `{` when expecting `(` messages_mosq.c(157): Error: found `;` when expecting `)` messages_mosq.c(158): Error: found `}` when expecting `;` following terminating `;` required after do-while statement messages_mosq.c(193): Error: `=`, `;` or `,` expected to end declaration instead of `{` messages_mosq.c(246): Error: found `}` when expecting `while` messages_mosq.c(247): Error: found `;` when expecting `(` messages_mosq.c(248): Error: expression expected, not `if` messages_mosq.c(248): Error: found `{` when expecting `)` messages_mosq.c(249): Error: found `return` when expecting `;` following terminating `;` required after do-while statement messages_mosq.c(249): Error: type-specifier missing for declaration of `MOSQ_ERR_SUCCESS` messages_mosq.c(253): Error: found `else` without a corresponding `if` statement messages_mosq.c(267): Error: found `}` when expecting `while` messages_mosq.c(269): Error: found `;` when expecting `(` messages_mosq.c(270): Error: expression expected, not `if` messages_mosq.c(270): Error: found `{` when expecting `)` messages_mosq.c(271): Error: found `return` when expecting `;` following terminating `;` required after do-while statement messages_mosq.c(271): Error: type-specifier missing for declaration of `MOSQ_ERR_SUCCESS` messages_mosq.c(279): Error: `=`, `;` or `,` expected to end declaration instead of `{` Wondering what the deal is here...

Link to Mosquitto library: https://github.com/eclipse/mosquitto

I accidentally hit the same bug while trying to compile the Nuklear library with DMD 2.101.1 on Manjaro Linux. Based on the error message and source code of assert.h I think ImportC is trying to use the following definition of assert: # define assert(expr) \ ((void) sizeof ((expr) ? 1 : 0), __extension__ ({ \ if (expr) \ ; /* empty */ \ else \ __assert_fail (#expr, __FILE__, __LINE__, __ASSERT_FUNCTION); \ })) The problem seems to be caused by 2 GCC extensions used in the assert macro which are not supported by ImportC: 1. Statement expressions (https://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html) (basically GCC treats code like this: ({statement1; statement2;}) as an expression) 2. __PRETTY_FUNCTION__ - this one is hidden inside the __ASSERT_FUNCTION macro

I also stumbled on this when trying to compile the tree-sitter run time library.

Might be able to support statement expressions by converting them to a nested function with no arguments. This won't work, though, with jumping into or out of a statement expression.

*** Issue 23619 has been marked as a duplicate of this issue. ***

@WalterBright created dlang/dmd pull request #15093 "fix Issue 23509 - ImportC: need statement expressions extension" fixing this issue: - fix Issue 23509 - ImportC: need statement expressions extension for GLibC's assert() https://github.com/dlang/dmd/pull/15093

dlang/dmd pull request #15093 "fix Issue 23509 - ImportC: need statement expressions extension" was merged into master: - a2e50cdbdcb4749c6198d06365054a5a292b4a0c by Walter Bright: fix Issue 23509 - ImportC: need statement expressions extension for GLibC's assert() https://github.com/dlang/dmd/pull/15093