Partial fix for #11552 Handle lambda return types (#5188)

Author: chrchr-github

lib/symboldatabase.cpp

@@ -2447,7 +2447,7 @@ Function::Function(const Tokenizer *mTokenizer,
     const Token *tok1 = setFlags(tok, scope);
 
     // find the return type
-    if (!isConstructor() && !isDestructor() && !isLambda()) {
+    if (!isConstructor() && !isDestructor()) {
         // @todo auto type deduction should be checked
         // @todo attributes and exception specification can also precede trailing return type
         if (Token::Match(argDef->link()->next(), "const|volatile| &|&&| .")) { // Trailing return type
@@ -2458,7 +2458,7 @@ Function::Function(const Tokenizer *mTokenizer,
                 retDef = argDef->link()->tokAt(3);
             else if (argDef->link()->strAt(3) == ".")
                 retDef = argDef->link()->tokAt(4);
-        } else {
+        } else if (!isLambda()) {
             if (tok1->str() == ">")
                 tok1 = tok1->next();
             while (Token::Match(tok1, "extern|virtual|static|friend|struct|union|enum"))
@@ -6895,6 +6895,23 @@ static const Function *getOperatorFunction(const Token * const tok)
     return nullptr;
 }
 
+static const Function* getFunction(const Token* tok) {
+    if (!tok)
+        return nullptr;
+    if (tok->function() && tok->function()->retDef)
+        return tok->function();
+    if (const Variable* lvar = tok->variable()) { // lambda
+        const Function* lambda{};
+        if (Token::Match(lvar->nameToken()->next(), "; %varid% = [", lvar->declarationId()))
+            lambda = lvar->nameToken()->tokAt(4)->function();
+        else if (Token::simpleMatch(lvar->nameToken()->next(), "{ ["))
+            lambda = lvar->nameToken()->tokAt(2)->function();
+        if (lambda && lambda->retDef)
+            return lambda;
+    }
+    return nullptr;
+}
+
 void SymbolDatabase::setValueTypeInTokenList(bool reportDebugWarnings, Token *tokens)
 {
     if (!tokens)
@@ -7012,10 +7029,10 @@ void SymbolDatabase::setValueTypeInTokenList(bool reportDebugWarnings, Token *to
 
             }
 
-            // function
-            else if (tok->previous() && tok->previous()->function() && tok->previous()->function()->retDef) {
+            // function or lambda
+            else if (const Function* f = getFunction(tok->previous())) {
                 ValueType valuetype;
-                if (parsedecl(tok->previous()->function()->retDef, &valuetype, mDefaultSignedness, mSettings, mIsCpp))
+                if (parsedecl(f->retDef, &valuetype, mDefaultSignedness, mSettings, mIsCpp))
                     setValueType(tok, valuetype);
             }
 

lib/tokenlist.cpp

@@ -735,11 +735,6 @@ static void compileTerm(Token *&tok, AST_state& state)
                     tok = tok->next();
                 else
                     throw InternalError(tok, "Syntax error. Unexpected tokens in designated initializer.", InternalError::AST);
-            } else if (Token::simpleMatch(tok, "{ }")) {
-                tok->astOperand1(state.op.top());
-                state.op.pop();
-                state.op.push(tok);
-                tok = tok->tokAt(2);
             }
         } else if (!state.cpp || !Token::Match(tok, "new|delete %name%|*|&|::|(|[")) {
             std::vector<Token*> inner;

test/testfunctions.cpp

@@ -119,6 +119,16 @@ class TestFunctions : public TestFixture {
         std::istringstream istr(code);
         ASSERT_LOC(tokenizer.tokenize(istr, filename), file, line);
 
+        // filter out ValueFlow messages..
+        const std::string debugwarnings = errout.str();
+        errout.str("");
+        std::istringstream istr2(debugwarnings);
+        std::string errline;
+        while (std::getline(istr2, errline)) {
+            if (errline.find("valueflow.cpp") == std::string::npos)
+                errout << errline << "\n";
+        }
+
         runChecks<CheckFunctions>(&tokenizer, settings_, this);
     }
 
@@ -1819,6 +1829,7 @@ class TestFunctions : public TestFixture {
     void checkLibraryMatchFunctions() {
         Settings s = settingsBuilder(settings).checkLibrary().build();
         s.daca = true;
+        s.debugwarnings = true;
 
         check("void f() {\n"
               "    lib_func();"
@@ -1934,6 +1945,8 @@ class TestFunctions : public TestFixture {
               "    q->push_back(1);\n"
               "}\n", "test.cpp", &s);
         TODO_ASSERT_EQUALS("",
+                           "[test.cpp:2]: (debug) auto token with no type.\n"
+                           "[test.cpp:4]: (debug) auto token with no type.\n"
                            "[test.cpp:3]: (information) --check-library: There is no matching configuration for function auto::push_back()\n"
                            "[test.cpp:5]: (information) --check-library: There is no matching configuration for function auto::push_back()\n",
                            errout.str());
@@ -1949,7 +1962,9 @@ class TestFunctions : public TestFixture {
         check("auto f() {\n"
               "    return std::runtime_error(\"abc\");\n"
               "}\n", "test.cpp", &s);
-        ASSERT_EQUALS("", errout.str());
+        TODO_ASSERT_EQUALS("",
+                           "[test.cpp:1]: (debug) auto token with no type.\n",
+                           errout.str());
 
         check("struct S {\n" // #11543
               "    S() {}\n"
@@ -2007,6 +2022,16 @@ class TestFunctions : public TestFixture {
               "    void f(int i) { push_back(i); }\n"
               "};\n", "test.cpp", &s);
         ASSERT_EQUALS("", errout.str());
+
+        check("void f() {\n"
+              "    auto g = []() -> std::string { return \"abc\"; };\n"
+              "    auto s = g();\n"
+              "    if (s.at(0)) {}\n"
+              "    auto h{ []() -> std::string { return \"xyz\"; } };\n"
+              "    auto t = h();\n"
+              "    if (t.at(0)) {}\n"
+              "};\n", "test.cpp", &s);
+        ASSERT_EQUALS("", errout.str());
     }
 
     void checkUseStandardLibrary1() {

test/testtokenize.cpp

@@ -6336,6 +6336,7 @@ class TestTokenizer : public TestFixture {
         ASSERT_EQUALS("var{{,{{,{", testAst("auto var{ {{},{}}, {} };"));
         ASSERT_EQUALS("fXYabcfalse==CD:?,{,{(", testAst("f({X, {Y, abc == false ? C : D}});"));
         ASSERT_EQUALS("stdvector::p0[{(return", testAst("return std::vector<int>({ p[0] });"));
+        ASSERT_EQUALS("vstdvector::{=", testAst("auto v = std::vector<int>{ };"));
 
         // Initialization with decltype(expr) instead of a type
         ASSERT_EQUALS("decltypex((", testAst("decltype(x)();"));

test/testvalueflow.cpp

@@ -6611,7 +6611,7 @@ class TestValueFlow : public TestFixture {
         ASSERT_EQUALS("", isKnownContainerSizeValue(tokenValues(code, "( ) ;"), 0));
 
         code = "std::vector<int> f() { return std::vector<int>{}; }";
-        TODO_ASSERT_EQUALS("", "values.size():0", isKnownContainerSizeValue(tokenValues(code, "{ } ;"), 0));
+        ASSERT_EQUALS("", isKnownContainerSizeValue(tokenValues(code, "{ } ;"), 0));
 
         code = "std::vector<int> f() { return {}; }";
         ASSERT_EQUALS("", isKnownContainerSizeValue(tokenValues(code, "{ } ;"), 0));