Add some more tests and comments

Author: localspook

clang-tools-extra/clang-tidy/utils/ExceptionAnalyzer.cpp

@@ -591,11 +591,14 @@ ExceptionAnalyzer::throwsException(const Stmt *St,
       Results.merge(Excs);
     }
   } else {
+    // Check whether any of this node's subexpressions throws.
     for (const Stmt *Child : St->children()) {
       ExceptionInfo Excs = throwsException(Child, Caught, CallStack);
       Results.merge(Excs);
     }
 
+    // If this node is a call to a function or constructor, also check
+    // whether the call itself throws.
     if (const auto *Call = dyn_cast<CallExpr>(St)) {
       if (const FunctionDecl *Func = Call->getDirectCallee()) {
         ExceptionInfo Excs =

clang-tools-extra/test/clang-tidy/checkers/bugprone/exception-escape.cpp

@@ -964,13 +964,27 @@ void throw_in_function_arg() noexcept {
 }
 // CHECK-MESSAGES: :[[@LINE-2]]:17: note: frame #0: unhandled exception of type 'int' may be thrown in function 'throw_in_function_arg' here
 
+int g(int, int, int);
+void throw_in_last_function_arg() noexcept {
+// CHECK-MESSAGES: :[[@LINE-1]]:6: warning: an exception may be thrown in function 'throw_in_last_function_arg' which should not throw exceptions
+  g(42, 67, false ? 0 : throw 1);
+}
+// CHECK-MESSAGES: :[[@LINE-2]]:25: note: frame #0: unhandled exception of type 'int' may be thrown in function 'throw_in_last_function_arg' here
+
 void indirect_throw_in_function_arg() noexcept {
 // CHECK-MESSAGES: :[[@LINE-1]]:6: warning: an exception may be thrown in function 'indirect_throw_in_function_arg' which should not throw exceptions
   f(thrower());
 }
-// CHECK-MESSAGES: :[[@LINE-19]]:3: note: frame #0: unhandled exception of type 'int' may be thrown in function 'thrower' here
+// CHECK-MESSAGES: :[[@LINE-26]]:3: note: frame #0: unhandled exception of type 'int' may be thrown in function 'thrower' here
 // CHECK-MESSAGES: :[[@LINE-3]]:5: note: frame #1: function 'indirect_throw_in_function_arg' calls function 'thrower' here
 
+void indirect_throw_from_lambda_in_function_arg() noexcept {
+// CHECK-MESSAGES: :[[@LINE-1]]:6: warning: an exception may be thrown in function 'indirect_throw_from_lambda_in_function_arg' which should not throw exceptions
+  f([] { throw 1; return 0; }());
+}
+// CHECK-MESSAGES: :[[@LINE-2]]:10: note: frame #0: unhandled exception of type 'int' may be thrown in function 'operator()' here
+// CHECK-MESSAGES: :[[@LINE-3]]:30: note: frame #1: function 'indirect_throw_from_lambda_in_function_arg' calls function 'operator()' here
+
 struct S {
   S(int) noexcept {}
 };
@@ -985,7 +999,7 @@ void indirect_throw_in_constructor_arg() noexcept {
 // CHECK-MESSAGES: :[[@LINE-1]]:6: warning: an exception may be thrown in function 'indirect_throw_in_constructor_arg' which should not throw exceptions
   S s = thrower();
 }
-// CHECK-MESSAGES: :[[@LINE-36]]:3: note: frame #0: unhandled exception of type 'int' may be thrown in function 'thrower' here
+// CHECK-MESSAGES: :[[@LINE-50]]:3: note: frame #0: unhandled exception of type 'int' may be thrown in function 'thrower' here
 // CHECK-MESSAGES: :[[@LINE-3]]:9: note: frame #1: function 'indirect_throw_in_constructor_arg' calls function 'thrower' here
 
 void weird_throw_in_call_subexpression() noexcept {