Simple handling of coroutines

lib/tokenize.cpp

@@ -4811,6 +4811,9 @@ bool Tokenizer::simplifyTokenList1(const char FileName[])
     // convert C++17 style nested namespaces to old style namespaces
     simplifyNestedNamespace();
 
+    // convert c++20 coroutines
+    simplifyCoroutines();
+
     // simplify namespace aliases
     simplifyNamespaceAliases();
 
@@ -12340,6 +12343,29 @@ void Tokenizer::simplifyNestedNamespace()
     }
 }
 
+void Tokenizer::simplifyCoroutines()
+{
+    if (!isCPP() || mSettings->standards.cpp < Standards::CPP20)
+        return;
+    for (Token *tok = list.front(); tok; tok = tok->next()) {
+        if (!tok->isName() || !Token::Match(tok, "co_return|co_yield|co_await"))
+            continue;
+        Token *end = tok->next();
+        while (end && end->str() != ";") {
+            if (Token::Match(end, "[({[]"))
+                end = end->link();
+            else if (Token::Match(end, "[)]}]"))
+                break;
+            end = end->next();
+        }
+        if (Token::simpleMatch(end, ";")) {
+            tok->insertToken("(");
+            end->previous()->insertToken(")");
+            Token::createMutualLinks(tok->next(), end->previous());
+        }
+    }
+}
+
 static bool sameTokens(const Token *first, const Token *last, const Token *other)
 {
     while (other && first->str() == other->str()) {

lib/tokenize.h

@@ -785,6 +785,13 @@ private:
      */
     void simplifyNestedNamespace();
 
+    /**
+     * Simplify coroutines - just put parentheses around arguments for
+     * co_* keywords so they can be handled like function calls in data
+     * flow.
+     */
+    void simplifyCoroutines();
+
     /**
     * Prepare ternary operators with parentheses so that the AST can be created
     * */

test/testtokenize.cpp

@@ -416,6 +416,8 @@ private:
         TEST_CASE(removeExtraTemplateKeywords);
 
         TEST_CASE(removeAlignas);
+
+        TEST_CASE(simplifyCoroutines);
     }
 
     std::string tokenizeAndStringify(const char code[], bool expand = true, Settings::PlatformType platform = Settings::Native, const char* filename = "test.cpp", bool cpp11 = true) {
@@ -6507,6 +6509,23 @@ private:
         const char expected[] = "unsigned char c [ sizeof ( float ) ] ;";
         ASSERT_EQUALS(expected, tokenizeAndStringify(code));
     }
+
+    void simplifyCoroutines() {
+        Settings settings;
+        settings.standards.cpp = Standards::CPP20;
+
+        const char code1[] = "generator<int> f() { co_yield start++; }";
+        const char expected1[] = "generator < int > f ( ) { co_yield ( start ++ ) ; }";
+        ASSERT_EQUALS(expected1, tokenizeAndStringify(code1, settings));
+
+        const char code2[] = "task<> f() { co_await foo(); }";
+        const char expected2[] = "task < > f ( ) { co_await ( foo ( ) ) ; }";
+        ASSERT_EQUALS(expected2, tokenizeAndStringify(code2, settings));
+
+        const char code3[] = "generator<int> f() { co_return 7; }";
+        const char expected3[] = "generator < int > f ( ) { co_return ( 7 ) ; }";
+        ASSERT_EQUALS(expected3, tokenizeAndStringify(code3, settings));
+    }
 };
 
 REGISTER_TEST(TestTokenizer)