Fix #11370 FP constStatement with lambda (#4570)

* Update tokenlist.cpp

* Update testincompletestatement.cpp

* Fix #11370 FP constStatement with lambda

* Format

lib/tokenlist.cpp

@@ -493,6 +493,17 @@ static Token * createAstAtToken(Token *tok, bool cpp);
 
 static Token* skipDecl(Token* tok, std::vector<Token*>* inner = nullptr)
 {
+    auto isDecltypeFuncParam = [](const Token* tok) -> bool {
+        if (!Token::simpleMatch(tok, ")"))
+            return false;
+        tok = tok->next();
+        while (Token::Match(tok, "*|&|&&|const"))
+            tok = tok->next();
+        if (Token::simpleMatch(tok, "("))
+            tok = tok->link()->next();
+        return Token::Match(tok, "%name%| ,|)");
+    };
+
     if (!Token::Match(tok->previous(), "( %name%"))
         return tok;
     Token *vartok = tok;
@@ -504,7 +515,7 @@ static Token* skipDecl(Token* tok, std::vector<Token*>* inner = nullptr)
                 return tok;
         } else if (Token::Match(vartok, "%var% [:=(]")) {
             return vartok;
-        } else if (Token::Match(vartok, "decltype|typeof (") && !Token::Match(tok->linkAt(1), ") [,)]")) {
+        } else if (Token::Match(vartok, "decltype|typeof (") && !isDecltypeFuncParam(tok->linkAt(1))) {
             if (inner)
                 inner->push_back(vartok->tokAt(2));
             return vartok->linkAt(1)->next();

test/testincompletestatement.cpp

@@ -709,6 +709,12 @@ private:
               "    (*s).i;\n"
               "}\n");
         ASSERT_EQUALS("[test.cpp:3]: (warning) Redundant code: Found unused member access.\n", errout.str());
+
+        check("int a[2];\n" // #11370
+              "void f() {\n"
+              "    auto g = [](decltype(a[0]) i) {};\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void vardecl() {

test/testtokenize.cpp

@@ -6243,6 +6243,10 @@ private:
         ASSERT_EQUALS("decltypexy+(yx+{", testAst("decltype(x+y){y+x};"));
         ASSERT_EQUALS("adecltypeac::(,decltypead::(,",
                       testAst("template <typename a> void b(a &, decltype(a::c), decltype(a::d));"));
+        ASSERT_EQUALS("g{([= decltypea0[(",
+                      testAst("auto g = [](decltype(a[0]) i) {};"));
+        ASSERT_EQUALS("g{([= decltypea0[(i&",
+                      testAst("auto g = [](decltype(a[0])& i) {};"));
 
         ASSERT_NO_THROW(tokenizeAndStringify("struct A;\n" // #10839
                                              "struct B { A* hash; };\n"