[Clang] FunctionEffect analysis was missing a CXXBindTemporaryExpr's implicit call to a destructor. (#166110)

This example is reduced from a discovery: resetting a shared pointer
from a nonblocking function is not diagnosed.

```
void nb23()
{
	struct X {
		int *ptr = nullptr;
		X() {}
		~X() { delete ptr; }
	};

	auto inner = []() [[clang::nonblocking]] {
		X();
	};
}
```

`shared_ptr<T>::reset()` creates a temporary `shared_ptr` and swaps it
with its current state. The temporary `shared_ptr` constructor is
nonblocking but its destructor potentially deallocates memory and is
unsafe.

Analysis was ignoring the implicit call in the AST to destroy the
temporary.

---------

Co-authored-by: Doug Wyatt <[email protected]>

Author: dougsonos

clang/docs/ReleaseNotes.rst

@@ -460,6 +460,7 @@ Bug Fixes to Attribute Support
 - Fix a crash when the function name is empty in the `swift_name` attribute. (#GH157075)
 - Fixes crashes or missing diagnostics with the `device_kernel` attribute. (#GH161905)
 - Fix handling of parameter indexes when an attribute is applied to a C++23 explicit object member function.
+- Fixed several false positives and false negatives in function effect (`nonblocking`) analysis. (#GH166078) (#GH166101) (#GH166110)
 
 Bug Fixes to C++ Support
 ^^^^^^^^^^^^^^^^^^^^^^^^

clang/lib/Sema/SemaFunctionEffects.cpp

@@ -1279,7 +1279,15 @@ class Analyzer {
       const CXXConstructorDecl *Ctor = Construct->getConstructor();
       CallableInfo CI(*Ctor);
       followCall(CI, Construct->getLocation());
+      return true;
+    }
 
+    bool VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *BTE) override {
+      const CXXDestructorDecl *Dtor = BTE->getTemporary()->getDestructor();
+      if (Dtor != nullptr) {
+        CallableInfo CI(*Dtor);
+        followCall(CI, BTE->getBeginLoc());
+      }
       return true;
     }
 

clang/test/Sema/attr-nonblocking-constraints.cpp

@@ -373,6 +373,33 @@ struct Unsafe {
   Unsafe(float y) [[clang::nonblocking]] : Unsafe(int(y)) {} // expected-warning {{constructor with 'nonblocking' attribute must not call non-'nonblocking' constructor 'Unsafe::Unsafe'}}
 };
 
+// Exercise cases of a temporary with a safe constructor and unsafe destructor.
+void nb23()
+{
+	struct X {
+		int *ptr = nullptr;
+		X() {}
+		~X() { delete ptr; } // expected-note 2 {{destructor cannot be inferred 'nonblocking' because it allocates or deallocates memory}}
+	};
+
+	auto inner = []() [[clang::nonblocking]] {
+		X(); // expected-warning {{lambda with 'nonblocking' attribute must not call non-'nonblocking' destructor 'nb23()::X::~X'}}
+	};
+
+	auto inner2 = [](X x) [[clang::nonblocking]] { // expected-warning {{lambda with 'nonblocking' attribute must not call non-'nonblocking' destructor 'nb23()::X::~X'}}
+	};
+
+}
+
+struct S2 { ~S2(); }; // expected-note 2 {{declaration cannot be inferred 'nonblocking' because it has no definition in this translation unit}}
+void nb24() {
+    S2 s;
+    [&]() [[clang::nonblocking]] {
+        [s]{ auto x = &s; }(); // expected-warning {{lambda with 'nonblocking' attribute must not call non-'nonblocking' destructor}} expected-note {{destructor cannot be inferred 'nonblocking' because it calls non-'nonblocking' destructor 'S2::~S2'}}
+        [=]{ auto x = &s; }(); // expected-warning {{lambda with 'nonblocking' attribute must not call non-'nonblocking' destructor}} expected-note {{destructor cannot be inferred 'nonblocking' because it calls non-'nonblocking' destructor 'S2::~S2'}}
+    }();
+}
+
 struct DerivedFromUnsafe : public Unsafe {
   DerivedFromUnsafe() [[clang::nonblocking]] {} // expected-warning {{constructor with 'nonblocking' attribute must not call non-'nonblocking' constructor 'Unsafe::Unsafe'}}
   DerivedFromUnsafe(int x) [[clang::nonblocking]] : Unsafe(x) {} // expected-warning {{constructor with 'nonblocking' attribute must not call non-'nonblocking' constructor 'Unsafe::Unsafe'}}