Allow base contract string constructor args with open curly braces (#479)

lib/parse.js

@@ -55,8 +55,21 @@ parse.ContractOrLibraryStatement = function(contract, expression) {
   // We need to define a method to pass coverage hashes into at top of each contract.
   // This lets us get a fresh stack for the hash and avoid stack-too-deep errors.
   if (expression.kind !== 'interface'){
-    const start = expression.range[0];
-    const end = contract.instrumented.slice(expression.range[0]).indexOf('{') + 1;
+    let start = 0;
+
+    // It's possible a base contract will have constructor string arg
+    // which contains an open curly brace. Skip ahead pass the bases...
+    if (expression.baseContracts && expression.baseContracts.length){
+      for (let base of expression.baseContracts ){
+        if (base.range[1] > start){
+          start = base.range[1];
+        }
+      }
+    } else {
+      start = expression.range[0];
+    }
+
+    const end = contract.instrumented.slice(start).indexOf('{') + 1;
     const loc = start + end;;
 
     (contract.injectionPoints[loc])

test/sources/solidity/contracts/statements/interpolation.sol

@@ -0,0 +1,13 @@
+pragma solidity ^0.5.0;
+
+contract Interpolated {
+    constructor(string memory a) public {
+      string memory b = a;
+    }
+}
+
+contract Test is Interpolated("abc{defg}"){
+    function a(uint x) public {
+        uint y = x;
+    }
+}

test/units/statements.js

@@ -23,6 +23,11 @@ describe('generic statements', () => {
     util.report(info.solcOutput.errors);
   })
 
+  it('should compile a base contract contructor with a string arg containing "{"', ()=> {
+    const info = util.instrumentAndCompile('statements/interpolation');
+    util.report(info.solcOutput.errors);
+  })
+
   it('should instrument a single statement (first line of function)', () => {
     const info = util.instrumentAndCompile('statements/single');
     util.report(info.solcOutput.errors);