Fix #14613 Crash in compilePrecedence2() (function called requires)

Author: web-flow

lib/tokenlist.cpp

@@ -1058,10 +1058,12 @@ static void compilePrecedence2(Token *&tok, AST_state& state)
             else
                 compileUnaryOp(tok, state, compileExpression);
             tok = tok2->link()->next();
-        } else if (Token::simpleMatch(tok->previous(), "requires {")
-                   || (Token::simpleMatch(tok->previous(), ")")
+        } else if ((Token::simpleMatch(tok->tokAt(-1), "requires {") && tok->tokAt(-1)->isKeyword())
+                   || (Token::simpleMatch(tok->tokAt(-1), ")")
                        && tok->linkAt(-1)
-                       && Token::simpleMatch(tok->linkAt(-1)->previous(), "requires ("))) {
+                       && Token::simpleMatch(tok->linkAt(-1)->tokAt(-1), "requires (") && tok->linkAt(-1)->tokAt(-1)->isKeyword())) {
+            if (!tok->link())
+                throw InternalError(tok, "Syntax error, token has no link.", InternalError::AST);
             tok->astOperand1(state.op.top());
             state.op.pop();
             state.op.push(tok);

test/testtokenize.cpp

@@ -8328,6 +8328,19 @@ class TestTokenizer : public TestFixture {
 
     void cppKeywordInCSource() {
         ASSERT_NO_THROW(tokenizeAndStringify("int throw() {}", dinit(TokenizeOptions, $.cpp = false)));
+
+        ASSERT_NO_THROW(tokenizeAndStringify("void requires(const char*);\n" // #14613
+                                             "void f() { requires(\"abc\"); }\n",
+                                             dinit(TokenizeOptions, $.cpp = false)));
+
+        ASSERT_NO_THROW(tokenizeAndStringify("void requires(const char*);\n"
+                                             "void f() { requires(\"abc\"); }\n",
+                                             dinit(TokenizeOptions, $.cpp = true, $.cppstd = Standards::CPP17)));
+
+        ASSERT_THROW_INTERNAL(tokenizeAndStringify("void requires(const char*);\n"
+                                                   "void f() { requires(\"abc\"); }\n",
+                                                   dinit(TokenizeOptions, $.cpp = true, $.cppstd = Standards::CPP20)),
+                                                   AST);
     }
 
     void cppcast() {