[C] static_assert in a for loop is not an extension #151955
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The original wording can be squinted at to pretend this was always allowed. GCC squints at it that way, so we're doing the same and no longer issuing an extension diagnostic for use of static_assert in the condition-1 of a for loop in C. Fixes llvm#149633
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Adding this to the 21.x milestone so we remember to backport it because the original changes introducing this diagnostic were added for 21.x |
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@llvm/pr-subscribers-clang Author: Aaron Ballman (AaronBallman) ChangesThe original wording can be squinted at to pretend this was always allowed. GCC squints at it that way, so we're doing the same and no longer issuing an extension diagnostic for use of static_assert in the condition-1 of a for loop in C. Fixes #149633 Full diff: https://github.com/llvm/llvm-project/pull/151955.diff 2 Files Affected:
diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index 3f89843a9081a..a5f92020f49f8 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -2284,7 +2284,11 @@ StmtResult Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
// we can diagnose if we don't see any variable declarations. This
// covers a case like declaring a typedef, function, or structure
// type rather than a variable.
- NonVarSeen = DI;
+ //
+ // Note, _Static_assert is acceptable because it does not declare an
+ // identifier at all, so "for object having" does not apply.
+ if (!isa<StaticAssertDecl>(DI))
+ NonVarSeen = DI;
}
}
// Diagnose if we saw a non-variable declaration but no variable
diff --git a/clang/test/Sema/for.c b/clang/test/Sema/for.c
index e16169aac0c4c..35c4720ef3305 100644
--- a/clang/test/Sema/for.c
+++ b/clang/test/Sema/for.c
@@ -26,6 +26,5 @@ void b11 (void) { for (static _Thread_local struct { int i; } s;s.i;); } /* c11-
#endif
void b12(void) {
- for(_Static_assert(1, "");;) {} /* c11-warning {{non-variable declaration in 'for' loop is a C23 extension}}
- c23-warning {{non-variable declaration in 'for' loop is incompatible with C standards before C23}} */
+ for(_Static_assert(1, "");;) {} /* okay, _Static_assert declares *no* identifiers */
}
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/cherry-pick cb50d78 |
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/pull-request #151999 |
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The original wording can be squinted at to pretend this was always allowed. GCC squints at it that way, so we're doing the same and no longer issuing an extension diagnostic for use of static_assert in the condition-1 of a for loop in C. Fixes llvm#149633 (cherry picked from commit cb50d78)
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The original wording can be squinted at to pretend this was always allowed. GCC squints at it that way, so we're doing the same and no longer issuing an extension diagnostic for use of static_assert in the condition-1 of a for loop in C.
Fixes #149633