Bug 15384 – assignment is sometimes still accepted as a condition

Problem seen with: DMD64 D Compiler v2.067.1 bool cond = true; do { // stuff } while (cond = false); yields: Error: assignment cannot be used as a condition, perhaps == was meant? But: bool cond = true; do { // stuff } while (cond = false, cond = false); passes the compiler without complaint, even though it also uses an assignment as a condition.

I assume that this has to do with the way in which the comma operator works. The compiler then sees it not as two assignments, but the output of the comma operator (which is just a value). Not sure how difficult it would be to get the compiler to track down into a comma operator, since you can do arbitrary work inside it.

Commits pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/95453495fdb38b9c596a977595ce23966fa55be7 fix Issue 15384 - assignment is sometimes still accepted as a condition 1. Add CommaExp.toBoolean to show error message. 2. Add checkAssignmentAsCondition and call it before semantic analysis to provide informative diagnostic. https://github.com/D-Programming-Language/dmd/commit/66ca6fe6cfe45f251664abed7304814c4e07af68 Merge pull request #5293 from 9rnsr/fix15384 Issue 15384 - assignment is sometimes still accepted as a condition

Commits pushed to stable at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/95453495fdb38b9c596a977595ce23966fa55be7 fix Issue 15384 - assignment is sometimes still accepted as a condition https://github.com/D-Programming-Language/dmd/commit/66ca6fe6cfe45f251664abed7304814c4e07af68 Merge pull request #5293 from 9rnsr/fix15384

Commit pushed to dmd-cxx at https://github.com/dlang/dmd https://github.com/dlang/dmd/commit/9ea575a943ae532743aa085400835e007c4f26c4 fix Issue 15384 - assignment is sometimes still accepted as a condition