Fix #15008 internalAstError for c++23 lambda (#8821)

Co-authored-by: chrchr-github <noreply@github.com>

Author: chrchr-github

lib/astutils.cpp

@@ -3304,12 +3304,12 @@ static T* findLambdaEndTokenGeneric(T* first)
         return nullptr;
     if (!maybeLambda(first->previous()))
         return nullptr;
-    if (!Token::Match(first->link(), "] (|{|<"))
+    if (!Token::Match(first->link(), "] [({<.]"))
         return nullptr;
     const Token* roundOrCurly = first->link()->next();
     if (roundOrCurly->link() && roundOrCurly->str() == "<")
         roundOrCurly = roundOrCurly->link()->next();
-    if (first->astOperand1() != roundOrCurly)
+    if (first->astOperand1() != roundOrCurly && roundOrCurly->str() != ".")
         return nullptr;
     T * tok = first;
 

lib/tokenlist.cpp

@@ -969,6 +969,21 @@ static bool isPrefixUnary(const Token* tok, bool cpp)
     return tok->strAt(-1) == ")" && iscast(tok->linkAt(-1), cpp);
 }
 
+template<class T, REQUIRES("T must be a Token class", std::is_convertible<T*, const Token*> )>
+static T* skipTrailingReturnType(T* tok)
+{
+    if (!Token::Match(tok, ".|->")) // TODO: fix simplification (see garbageCode228)
+        return tok;
+    tok = tok->next();
+    while (Token::Match(tok, "%type%|%name%|::|&|&&|*|<|(")) {
+        if (tok->link())
+            tok = tok->link()->next();
+        else
+            tok = tok->next();
+    }
+    return tok;
+}
+
 /**
  * @throws InternalError thrown if unexpected tokens are encountered
  */
@@ -1013,7 +1028,7 @@ static void compilePrecedence2(Token *&tok, AST_state& state)
             else
                 compileUnaryOp(tok, state, compileScope);
         } else if (tok->str() == "[") {
-            if (state.cpp && isPrefixUnary(tok, /*cpp*/ true) && Token::Match(tok->link(), "] (|{|<")) { // Lambda
+            if (state.cpp && isPrefixUnary(tok, /*cpp*/ true) && Token::Match(tok->link(), "] [({<.]")) { // Lambda
                 // What we do here:
                 // - Nest the round bracket under the square bracket.
                 // - Nest what follows the lambda (if anything) with the lambda opening [
@@ -1062,7 +1077,10 @@ static void compilePrecedence2(Token *&tok, AST_state& state)
                         continue;
                     }
                 } else {
-                    Token* const curlyBracket = squareBracket->link()->next();
+                    Token* curlyBracket = squareBracket->link()->next();
+                    curlyBracket = skipTrailingReturnType(curlyBracket);
+                    if (!Token::simpleMatch(curlyBracket, "{"))
+                        throw InternalError(tok, "Syntax error in lambda", InternalError::AST);
                     squareBracket->astOperand1(curlyBracket);
                     state.op.push(squareBracket);
                     tok = curlyBracket->link() ? curlyBracket->link()->next() : nullptr;
@@ -1507,15 +1525,7 @@ const Token* findLambdaEndTokenWithoutAST(const Token* tok) {
         tok = tok->link()->next();
     if (Token::simpleMatch(tok, "mutable"))
         tok = tok->next();
-    if (Token::Match(tok, ".|->")) { // trailing return type
-        tok = tok->next();
-        while (Token::Match(tok, "%type%|%name%|::|&|&&|*|<|(")) {
-            if (tok->link())
-                tok = tok->link()->next();
-            else
-                tok = tok->next();
-        }
-    }
+    tok = skipTrailingReturnType(tok);
     if (!(Token::simpleMatch(tok, "{") && tok->link()))
         return nullptr;
     return tok->link()->next();

test/testtokenize.cpp

@@ -7664,6 +7664,8 @@ class TestTokenizer : public TestFixture {
         ASSERT_EQUALS("sf.{(i[{={", testAst("void g(int i) { S s{ .f = { [i]() {} } }; }\n"));
 
         ASSERT_EQUALS("{([", testAst("void f() { []() {}; }\n")); // #13471
+
+        ASSERT_EQUALS("x{=[= 0return", testAst("void f() { auto x = [=] -> int { return 0; }; }\n")); // #15008
     }
 
     void astcase() {

test/testvalueflow.cpp

@@ -8097,7 +8097,7 @@ class TestValueFlow : public TestFixture {
         code = "void f(int& r) {\n" // #13515
                "    [0].p = &r;\n"
                "}\n";
-        (void)valueOfTok(code, "=");
+        ASSERT_THROW_INTERNAL(valueOfTok(code, "="), AST);
     }
 
     void valueFlowCrash() {