[clang] [alpha.webkit.UncountedLocalVarsChecker] Ignore a VarDecl in "if" with trivial "then" (PR #171764)

[Balázs Benics via cfe-commits]

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@@ -492,4 +492,42 @@ namespace virtual_function {
     auto* baz = &*obj;
     // expected-warning at -1{{Local variable 'baz' is uncounted and unsafe [alpha.webkit.UncountedLocalVarsChecker]}}
   }
-}
\ No newline at end of file
+}
+
+namespace vardecl_in_if_condition {
+  RefCountable* provide();
+
+  RefCountable* get() {
+    if (auto* obj = provide())
+      return obj; // no warning
+    return nullptr;
+  }
+
+  RefCountable* get_non_trivial_then() {
+    if (auto* obj = provide()) // expected-warning{{Local variable 'obj' is uncounted and unsafe [alpha.webkit.UncountedLocalVarsChecker]}}
+      return obj->next();
+    return nullptr;
+  }
+
+  RefCountable* get_non_trivial_else() {
+    if (auto* obj = provide())
+      return obj;
+    else
+      return provide()->next();
+    return nullptr;
+  }
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steakhal wrote:

As you wish.

https://github.com/llvm/llvm-project/pull/171764