test(coverage): lexer contract testing (#54)

source: https://gitlab.com/veox/pygments-lexer-solidity/-/blob/master/example.sol

Author: sambacha

tests/Lexer_Coverage.t.sol

@@ -0,0 +1,255 @@
+/// SPDX-License-Identifier: BSD-2-Clause
+
+pragma solidity ^0.6.0 <0.8.0;
+pragma ABIEncoderV2;
+pragma experimental SMTChecker;
+
+/**********************************************************************
+ *                             example.sol                            *
+ **********************************************************************/
+
+// Code in this contract is not meant to work (or be a good example).
+// It is meant to demonstrate good syntax highlighting by the lexer,
+// even if otherwise hazardous.
+
+// Comments relevant to the lexer are single-line.
+/* Comments relevant to the code are multi-line. */
+
+library Assembly {
+    function junk(address _addr) private returns (address _ret) {
+        assembly {
+            let tmp := 0
+
+            // nested code block
+            let mulmod_ := 0 { // evade collision with `mulmod`
+                let tmp:=sub(mulmod_,1) // `tmp` is not a label
+                mulmod_ := tmp
+            }
+            /* guess what mulmod_ is now... */
+        _loop: // JIC, dots are invalid in labels
+            let i := 0x10
+        loop:
+            // Escape sequences in comments are not parsed.
+            /* Not sure what's going on here, but it sure is funky!
+             \o/ \o/ \o/ \o/ \o/ \o/ \o/ \o/ \o/ \o/ \o/ \o/ \o/ */
+            mulmod(_addr, mulmod_, 160)
+            
+            0x1 i sub // instructional style
+            i =: tmp /* tmp not used */
+            
+            jumpi(loop, not(iszero(i)))
+            
+            mstore(0x0, _addr)
+            return(0x0, 160)
+        }
+    }
+}
+
+contract Strings {
+    // `double` is not a keyword (yet)
+    string double = "This\ is a string\nwith \"escapes\",\
+and it's multi-line. // no comment"; // comment ok // even nested :)
+    string single = 'This\ is a string\nwith "escapes",\
+and it\'s multi-line. // no comment'; // same thing, single-quote
+    string hexstr = hex'537472696e67732e73656e6428746869732e62616c616e6365293b';
+
+    fallback() external payable virtual {}
+
+    receive() external payable {
+        revert();
+    }
+}
+
+contract Types is Strings {
+    using Assembly for Assembly;
+
+    bytes stringsruntime = type(Strings).runtimeCode;
+    
+    // typesM (compiler chokes on invalid)
+    int8 i8;           // valid
+    //int10 i10;       // invalid
+    uint256 ui256;     // valid
+    //uint9001 ui9001; // invalid
+    bytes1 b1;         //valid
+    //bytes42 b42;     // invalid - M out of range for `bytes`
+    
+    // typesMxN (compiler chokes on invalid)
+    fixed8x0 f8x0;           // valid
+    fixed8x1 f8x1;           // valid
+    fixed8x8 f8x8;           // valid
+    //fixed0x8 f0x8;         // invalid since MxN scheme changed
+    ufixed256x80 uf256x80;   // valid
+    //ufixed42x217 uf42x217; // invalid - M must be multiple of 8, N <= 80
+
+    // special cases (internally not types)
+    string str; // dynamic array (not a value-type)
+    bytes bs; // same as above
+    //var v = 5; // `var` is a keyword, not a type, and compiler chokes
+    uint unu$ed; // `var` is highlighted, though, and `$` is a valid char
+
+    address a = "0x1"; // lexer parses as string
+    struct AddressMap {
+        address origin;
+        address result;
+        address sender;
+        bool touched;
+    }
+    mapping (address => AddressMap) touchedMe;
+
+    function failOnNegative(int8 _arg)
+        private
+        pure
+        returns (uint256)
+    {
+        /* implicit type conversion from `int8` to `uint256` */
+        return _arg;
+    }
+
+    // some arithmetic operators + built-in names
+    function opportunisticSend(address k) private {
+        /* `touchedMe[k].result` et al are addresses, so
+           `send()` available */
+        touchedMe[k].origin.send(uint256(k)**2 % 100 finney);
+        touchedMe[k].result.send(1 wei);
+        touchedMe[k].sender.send(mulmod(1 szabo, k, 42));
+    }
+
+    fallback() external payable override {
+        /* inferred type: address */
+        var k = msg.sender;
+        /* inferred type: `ufixed0x256` */
+        var v = 1/42;
+        /* can't be `var` - location specifier requires explicit type */
+        int negative = -1;
+
+        // valid syntax, unexpected result - not our problem
+        ui256 = failOnNegative(negative);
+        
+        // logic operators
+        if ((!touchedMe[msg.sender].touched &&
+             !touchedMe[tx.origin].touched) ||
+            ((~(msg.sender * v + a)) % 256 == 42)
+        ) {
+            address garbled = Assembly.junk(a + msg.sender);
+
+            /* create a new AddressMap struct in storage */
+            AddressMap storage tmp;
+
+            // TODO: highlight all known internal keywords?
+            tmp.origin = tx.origin;
+            tmp.result = garbled;
+            tmp.sender = msg.sender;
+            tmp.touched = true;
+
+            /* does this link-by-reference as expected?.. */
+            touchedMe[msg.sender] = tmp;
+            touchedMe[tx.origin] = tmp;
+        }
+        else {
+            /* weak guard against re-entry */
+            touchedMe[k].touched = false;
+            
+            opportunisticSend(k);
+            
+            delete touchedMe[k];
+            /* these probably do nothing... */
+            delete touchedMe[msg.sender];
+            delete touchedMe[tx.origin];
+        }
+    }
+}
+
+/**
+   \brief Examples of bad practices.
+
+   TODO: This special NatSpec notation is not parsed yet.
+
+   @author Noel Maersk
+ */
+/// Triple-slash NatSpec should work.
+/// @title Some examples of bad practices.
+/// @author Noel Maersk
+/// @notice Very old, might've been "fixed" by obsoletion.
+/// @dev This is a dummy comment.
+/// @custom:unmaintained This code is not maintained.
+
+contract BadPractices {
+    address constant creator; /* `internal` by default */
+    address private owner; /* forbid inheritance */
+    bool mutex;
+
+    modifier critical {
+        assert(!mutex);
+        mutex = true;
+        _;
+        mutex = false;
+    }
+    
+    constructor() external {
+        creator = tx.origin;
+        owner = msg.sender;
+    }
+
+    /* Dangerous - function public, and doesn't check who's calling. */
+    function withdraw(uint _amount)
+        public
+        critical
+        returns (bool)
+    { /* `mutex` set via modifier */
+        /* Throwing on failed call may be dangerous. Consider
+           returning false instead?.. */
+        require(msg.sender.call.value(_amount)());
+        return true;
+    } /* `mutex` reset via modifier */
+    
+    /* fallback */
+    fallback() external payable {
+        /* `i` will be `uint8`, so this is an endless loop
+           that will consume all gas and eventually throw.
+         */
+        for (var i = 0; i < 257; i++) {
+            owner++;
+        }
+    }
+
+    /* receive()?.. nah, why bother */
+}
+
+/* /* /* /* /* /* /* /* /* /* /* /* /* /* /* /* /* /* /* /* /* /* /*
+// A regular multi-line comment closure, including an escaped variant as
+// demonstrated shortly, should close the comment; note that the lexer
+// should not be nesting multi-line comments.
+//
+// If the comment is still shown as "open", then a
+//
+//                !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+//                !!! MALICIOUS CODE SEGMENT !!!
+//                !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+//
+// can be erroneously thought of as inactive, and left unread.
+// In fact, the compiler will produce executable code it, possibly
+// overriding the program above.
+//
+// It is imperative that syntax highlighters do parse it if either of
+// `* /` or `\* /` (with space removed) are present.
+//
+// Now, let's party! :) \*/
+
+contract MoreBadPractices is BadPractices {
+    uint balance;
+
+    fallback() external payable override {
+        balance += msg.value;
+        if (!msg.sender.send(this.balance / 10)) throw;
+        balance -= this.balance;
+    }
+}
+
+/*
+// Open comment to EOF. Compiler chokes on this, but it's useful for
+// highlighting to show that there's an unmatched multi-line comment
+// open.
+
+contract CommentToEndOfFile is MoreBadPractices {
+    fallback() external payable override {}
+}