keyword "interface" not accepted (compile fails)

[d10r]

This has already been asked in the Gitter channel by others, but not answered (as far as I could see).

---

Issue

Compiling files containing interface definitions fails with

SyntaxError: Error parsing /somepath/somefile.sol: Expected "contract", "import", "library", "pragma", "using", comment, end of input, end of line, or whitespace but "i" found.

Steps to Reproduce

Create a solidity file containing an interface definition, e.g.

interface IDummy {
    function dummy();
}

and try to have it compiled with truffle compile.

Expected Behavior

Since the interface keyword is supported since Solidity 0.4.11 (seeChangelog), truffle - which is using solc 0.4.15 - should recognize it.

In Remix IDE, the behaviour is as expected. If the compiler version is at least 0.4.11, files with interface definitions compile.

Actual Results

$ truffle compile
SyntaxError: Error parsing /home/didi/src/p4p/blockchain/contracts/PlayToken.sol: Expected "contract", "import", "library", "pragma", "using", comment, end of input, end of line, or whitespace but "i" found. Line: 4, Column: 1
    at peg$buildStructuredError (/home/didi/.nvm/versions/node/v6.11.0/lib/node_modules/truffle/build/cli.bundled.js:181971:12)
    at Object.peg$parse [as parse] (/home/didi/.nvm/versions/node/v6.11.0/lib/node_modules/truffle/build/cli.bundled.js:185570:11)
    at Object.parse (/home/didi/.nvm/versions/node/v6.11.0/lib/node_modules/truffle/build/cli.bundled.js:83782:23)
    at /home/didi/.nvm/versions/node/v6.11.0/lib/node_modules/truffle/build/cli.bundled.js:59136:36
    at /home/didi/.nvm/versions/node/v6.11.0/lib/node_modules/truffle/build/cli.bundled.js:49114:5
    at /home/didi/.nvm/versions/node/v6.11.0/lib/node_modules/truffle/build/cli.bundled.js:60660:16
    at next (/home/didi/.nvm/versions/node/v6.11.0/lib/node_modules/truffle/build/cli.bundled.js:69109:18)
    at /home/didi/.nvm/versions/node/v6.11.0/lib/node_modules/truffle/build/cli.bundled.js:49099:7
    at /home/didi/.nvm/versions/node/v6.11.0/lib/node_modules/truffle/build/cli.bundled.js:96498:5
    at /home/didi/.nvm/versions/node/v6.11.0/lib/node_modules/truffle/build/cli.bundled.js:69014:16

Environment

• Operating System: Ubuntu 14.04.5 LTS
• Truffle version: Truffle v3.4.9 (core: 3.4.8), Solidity v0.4.15 (solc-js)
• Ethereum client:
• node version: v6.11.0 (also tested with v8.4.0)
• npm version: 3.10.10 (also tested with 5.3.0)

[mrhn]

Having the same problem with solc 0.4.15 also... fresh install this friday.

[kevbry]

Same issue.

Environment:

• OS: Windows 7
• Truffle v3.4.9 (core: 3.4.8)
• Solidity v0.4.15 (solc-js)
• Node version 8.4.0
• NPM version 5.3.0

[hotblade]

Same problem.

• MacOS Sierra
• Truffle 3.4.9
• Solc 0.4.16+commit.d7661dd9.Darwin.appleclang

[dlocation]

We must wait for update solidity-parser package that implement interface support PR has been merged yet but realease not published yet https://github.com/ConsenSys/solidity-parser/pull/68

OR You can swap to beta version of truffle.