fix #13561: Syntax error reported when a _Generic is used in if condition (danmar#7282)

Author: ludviggunne

lib/tokenlist.cpp

@@ -451,6 +451,7 @@ namespace {
         bool cpp;
         int assign{};
         bool inCase{}; // true from case to :
+        bool inGeneric{};
         bool stopAtColon{}; // help to properly parse ternary operators
         const Token* functionCallEndPar{};
         explicit AST_state(bool cpp) : cpp(cpp) {}
@@ -706,11 +707,31 @@ static void compileUnaryOp(Token *&tok, AST_state& state, void (*f)(Token *&tok,
     state.op.push(unaryop);
 }
 
+static void skipGenericType(Token *&tok)
+{
+    Token *skip = tok;
+    while (Token::Match(skip, "%name%|*|:|(")) {
+        if (skip->link()) {
+            skip = skip->link()->next();
+            continue;
+        }
+        if (Token::simpleMatch(skip, ":")) {
+            tok = skip->next();
+            return;
+        }
+        skip = skip->next();
+    }
+}
+
 static void compileBinOp(Token *&tok, AST_state& state, void (*f)(Token *&tok, AST_state& state))
 {
     Token *binop = tok;
     if (f) {
         tok = tok->next();
+        if (Token::simpleMatch(binop, ",") && state.inGeneric)
+            skipGenericType(tok);
+        const bool inGenericSaved = state.inGeneric;
+        state.inGeneric = false;
         if (Token::Match(binop, "::|. ~"))
             tok = tok->next();
         state.depth++;
@@ -719,6 +740,7 @@ static void compileBinOp(Token *&tok, AST_state& state, void (*f)(Token *&tok, A
         if (state.depth > AST_MAX_DEPTH)
             throw InternalError(tok, "maximum AST depth exceeded", InternalError::AST);
         state.depth--;
+        state.inGeneric = inGenericSaved;
     }
 
     // TODO: Should we check if op is empty.
@@ -1048,6 +1070,9 @@ static void compilePrecedence2(Token *&tok, AST_state& state)
             continue;
         } else if (tok->str() == "(" &&
                    (!iscast(tok, state.cpp) || Token::Match(tok->previous(), "if|while|for|switch|catch"))) {
+            const bool inGenericSaved = state.inGeneric;
+            if (Token::simpleMatch(tok->previous(), "_Generic"))
+                state.inGeneric = true;
             Token* tok2 = tok;
             tok = tok->next();
             const bool opPrevTopSquare = !state.op.empty() && state.op.top() && state.op.top()->str() == "[";
@@ -1066,6 +1091,7 @@ static void compilePrecedence2(Token *&tok, AST_state& state)
                 else
                     compileUnaryOp(tok, state, nullptr);
             }
+            state.inGeneric = inGenericSaved;
             tok = tok->link()->next();
             if (Token::simpleMatch(tok, "::"))
                 compileBinOp(tok, state, compileTerm);

test/testtokenize.cpp

@@ -464,6 +464,8 @@ class TestTokenizer : public TestFixture {
         TEST_CASE(funcnameInParenthesis1); // #13554
         TEST_CASE(funcnameInParenthesis2); // #13578
         TEST_CASE(funcnameInParenthesis3); // #13585
+
+        TEST_CASE(genericInIf); // #13561
     }
 
 #define tokenizeAndStringify(...) tokenizeAndStringify_(__FILE__, __LINE__, __VA_ARGS__)
@@ -8389,6 +8391,12 @@ class TestTokenizer : public TestFixture {
         ASSERT_EQUALS(par->astOperand1(), f->astParent() /* :: */);
         ASSERT(Token::simpleMatch(par->astOperand2(), ","));
     }
+
+    void genericInIf() { // #13561
+        const char code[] = "  if (_Generic(s, char * : 1, const float * : (a ? b, c : d), volatile int * : 3, default : 0)) {}";
+        const char ast[] = "(( if (( _Generic (, (, (, (, s 1) (? a (: (, b c) d))) 3) 0)))";
+        ASSERT_EQUALS(ast, testAst(code, AstStyle::Z3));
+    }
 };
 
 REGISTER_TEST(TestTokenizer)