================
@@ -1,45 +1,99 @@
-// RUN: %clang_cc1 -verify -std=c2y -Wall -pedantic -Wno-unused %s
+// RUN: %clang_cc1 -verify=expected,c2y -std=c2y -Wall -pedantic -Wno-unused %s
+// RUN: %clang_cc1 -verify=expected,c89-23 -std=c23 -Wall -pedantic
-Wno-unused %s
+// RUN: %clang_cc1 -verify=expected,c89-23 -std=c17 -Wall -pedantic
-Wno-unused %s
+// RUN: %clang_cc1 -verify=expected,c89-23 -std=c11 -Wall -pedantic
-Wno-unused %s
+// RUN: %clang_cc1 -verify=expected,c89-23 -std=c99 -Wall -pedantic
-Wno-unused %s
+// RUN: %clang_cc1 -verify=expected,c89-23 -std=c89 -Wall -pedantic
-Wno-unused -Wno-comment %s
-/* WG14 N3410: No
+/* WG14 N3410: Clang 24
* Slay Some Earthly Demons XI
*
* It is now ill-formed for the same identifier within a TU to have both
* internal and external linkage.
*/
-void func1() {
- extern int a; // #a
+void func1(void) {
+ extern int a; /* #a */
}
-// This 'a' is the same as the one declared extern above.
-static int a; /* expected-error {{static declaration of 'a' follows non-static
declaration}}
+/* This 'a' is the same as the one declared extern above. */
+static int a; /* c2y-error {{static declaration of 'a' follows non-static
declaration}}
+ c89-23-error {{static declaration of 'a' follows non-static
declaration; behavior is undefined}}
expected-note@#a {{previous declaration is here}}
*/
static int b;
-void func2() {
- // This 'b' is the same as the one declaraed static above, but this is not
- // ill-formed because of C2y 6.2.2p4, which gives this variable internal
- // linkage because the previous declaration had internal linkage.
- extern int b; // Ok
+void func2(void) {
+ /* This 'b' is well-formed, because C2y 6.2.2p6 makes it "inherit" the
+ static linkage of `static int b` above, because the latter is visible.
+ */
+ extern int b; /* Ok */
}
-static int c, d;
-void func3() {
- int c; // no linkage, different object from the one declared above.
- for (int d;;) {
- // This 'c' is the same as the one declared at file scope, but because of
- // the local scope 'c', the file scope 'c' is not visible.
- // FIXME: This should be diagnosed under N3410.
- extern int c;
- // This 'd' is the same as the one declared at file scope as well, but
- // because of the 'd' declared within the for loop, the file scope 'd' is
- // also not visible, same as with 'c'.
- // FIXME: This should be diagnosed under N3410.
- extern int d;
+static int c, d; /* expected-note 2 {{previous definition is here}} */
+void func3(void) {
+ int c; /* no linkage, different object from the one declared above. */
+ {
+ int d; /* no linkage, different object from the file-scope 'd'. */
+ {
+ /* This 'c' is the same as the one declared at file scope, but because
+ of the local scope 'c', the file scope 'c' is not visible. */
+ extern int c; /* c2y-error {{variable 'c' cannot be declared with
external linkage following a declaration with internal linkage}}
----------------
AaronBallman wrote:
Here's an additional test case; I suspect we're going to get surprising (but
correct) diagnostic behavior, but I think it's fine to have a FIXME comment
saying it would be nice to improve the behavior:
```
static int c;
int main() {
{
extern int c; // note: lol, surprise, this has internal linkage
}
int c;
{
extern int c; // error: cannot be declared extern following internal
}
}
```
We can address the usability issue if a user ever hits the problem, which I
would be surprised if they did because you have to work at it.
https://github.com/llvm/llvm-project/pull/193567
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