[clang] Enable unguarded availability diagnostic on instantiated template functions (PR #91699)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Helena Kotas (hekota)

<details>
<summary>Changes</summary>

Availability diagnostic in instantiated template functions was intentionally skipped in the original [commit](https://github.com/llvm/llvm-project/commit/5cd57177a51abc7b0bfe18f70566572dbccab9a0) years ago with a FIXME note.

I ran into this when working on diagnostics for HLSL. When I remove the skip, it seems to be working just fine outputting expected messages. So, unless I am missing something, I would keep it enabled and use it for checking availability in HLSL templates as well.

---
Full diff: https://github.com/llvm/llvm-project/pull/91699.diff


2 Files Affected:

- (modified) clang/lib/Sema/SemaAvailability.cpp (-5) 
- (modified) clang/test/SemaObjC/unguarded-availability.m (+7-4) 


``````````diff
diff --git a/clang/lib/Sema/SemaAvailability.cpp b/clang/lib/Sema/SemaAvailability.cpp
index 846a31a796730..5b0f34d1aa3aa 100644
--- a/clang/lib/Sema/SemaAvailability.cpp
+++ b/clang/lib/Sema/SemaAvailability.cpp
@@ -928,11 +928,6 @@ void Sema::DiagnoseUnguardedAvailabilityViolations(Decl *D) {
   Stmt *Body = nullptr;
 
   if (auto *FD = D->getAsFunction()) {
-    // FIXME: We only examine the pattern decl for availability violations now,
-    // but we should also examine instantiated templates.
-    if (FD->isTemplateInstantiation())
-      return;
-
     Body = FD->getBody();
 
     if (auto *CD = dyn_cast<CXXConstructorDecl>(FD))
diff --git a/clang/test/SemaObjC/unguarded-availability.m b/clang/test/SemaObjC/unguarded-availability.m
index d0e23eabcb598..3a38c3b40c4d6 100644
--- a/clang/test/SemaObjC/unguarded-availability.m
+++ b/clang/test/SemaObjC/unguarded-availability.m
@@ -177,16 +177,19 @@ void justAtAvailable(void) {
 
 #ifdef OBJCPP
 
-int f(char) AVAILABLE_10_12;
+int f(char) AVAILABLE_10_12; // #f_char_def
 int f(int);
 
 template <class T> int use_f() {
-  // FIXME: We should warn here!
-  return f(T());
+  // expected-warning@#f_call {{'f' is only available on macOS 10.12 or newer}}
+  // expected-note@#f_char_inst {{in instantiation of function template specialization 'use_f<char>' requested here}}
+  // expected-note@#f_char_def {{'f' has been marked as being introduced in macOS 10.12 here, but the deployment target is macOS 10.9}}
+  // expected-note@#f_call {{enclose 'f' in an @available check to silence this warning}}
+  return f(T()); // #f_call
 }
 
 int a = use_f<int>();
-int b = use_f<char>();
+int b = use_f<char>(); // #f_char_inst
 
 template <class> int use_at_available() {
   if (@available(macos 10.12, *))

``````````

</details>


https://github.com/llvm/llvm-project/pull/91699