Fix #14894: false positive: co_return not recognized as return in combination with {} (#8741)

Author: ludviggunne

lib/astutils.cpp

@@ -3918,3 +3918,23 @@ const Token *skipUnreachableBranch(const Token *tok)
 
     return tok;
 }
+
+bool isEscapeKeyword(const Token *tok, const Settings &settings)
+{
+    if (!tok)
+        return false;
+
+    if (tok->str() == "return")
+        return true;
+
+    if (!tok->isCpp())
+        return false;
+
+    if (tok->str() == "throw")
+        return true;
+
+    if (settings.standards.cpp < Standards::CPP20)
+        return false;
+
+    return tok->str() == "co_return";
+}

lib/astutils.h

@@ -463,4 +463,6 @@ bool isUnreachableOperand(const Token *tok);
 
 const Token *skipUnreachableBranch(const Token *tok);
 
+bool isEscapeKeyword(const Token *tok, const Settings &settings);
+
 #endif // astutilsH

lib/forwardanalyzer.cpp

@@ -144,7 +144,7 @@ namespace {
                 // If we are in a loop then jump to the end
                 if (out)
                     *out = loopEnds.back();
-            } else if (Token::Match(tok, "return|throw")) {
+            } else if (isEscapeKeyword(tok, settings)) {
                 traverseRecursive(tok->astOperand2(), f, traverseUnknown);
                 traverseRecursive(tok->astOperand1(), f, traverseUnknown);
                 return Break(Analyzer::Terminate::Escape);

test/testnullpointer.cpp

@@ -146,6 +146,7 @@ class TestNullPointer : public TestFixture {
         TEST_CASE(nullpointer106); // #13682
         TEST_CASE(nullpointer107); // #13682 (FP/FN cases around guards that depend on the pointer indirectly)
         TEST_CASE(nullpointer108);
+        TEST_CASE(nullpointer109);
         TEST_CASE(nullpointer_addressOf); // address of
         TEST_CASE(nullpointerSwitch); // #2626
         TEST_CASE(nullpointer_cast); // #4692
@@ -3115,6 +3116,18 @@ class TestNullPointer : public TestFixture {
         ASSERT_EQUALS("[test.cpp:4:10]: (error) Null pointer dereference: r [nullPointer]\n", errout_str());
     }
 
+    void nullpointer109()
+    {
+        check("boost::asio::awaitable<int> test()\n"
+              "{\n"
+              "    const auto *s = getStr();\n"
+              "    if(!s) co_return int{1};\n"
+              "    std::print(\"{}\",*s);\n"
+              "    co_return int{9};\n"
+              "}\n");
+        ASSERT_EQUALS("", errout_str());
+    }
+
     void nullpointer_addressOf() { // address of
         check("void f() {\n"
               "  struct X *x = 0;\n"