"pragma-on-top" rule can fix position of "pragma experimental" statements

lib/rules/pragma-on-top.js

@@ -5,6 +5,8 @@
 
 "use strict";
 
+const { EOL } = require("os");
+
 module.exports = {
 
     meta: {
@@ -62,7 +64,7 @@ module.exports = {
                 message: `"${pragmaCode}" should be at the top of the file.`,
                 fix: function(fixer) {
                     return [fixer.remove(node),
-                        fixer.insertTextBefore(pragmaParent.body [0], pragmaCode + "\n")];
+                        fixer.insertTextBefore(pragmaParent.body [0], `${pragmaCode}${EOL}`)];
                 }
             });
 
@@ -86,15 +88,20 @@ module.exports = {
                     return;
                 }
 
-                // The moment we find 1 node not allowed above exp. pragma, report and exit.
-                // TODO: write fix() for this issue:
-                //   - Remove exp. pragma from current position
-                //   - Place it right before childNode.start
+                // We found the first node not allowed above experimental pragma, report and exit.
+                const pragmaCode = context.getSourceCode().getText(node);
+
                 if (nodesAllowedAbove.indexOf(childNode.type) < 0) {
-                    return context.report({
+                    const errObject = {
                         node,
+                        fix(fixer) {
+                            return [fixer.remove(node),
+                                fixer.insertTextBefore(childNode, `${pragmaCode}${EOL}`)];
+                        },
                         message: "Experimental Pragma must precede everything except Solidity Pragma."
-                    });
+                    };
+
+                    return context.report(errObject);
                 }
             }
         }

test/lib/rules/pragma-on-top/pragma-on-top.js

@@ -5,7 +5,8 @@
 
 "use strict";
 
-let Solium = require("../../../../lib/solium");
+const { EOL } = require("os");
+const Solium = require("../../../../lib/solium");
 
 let userConfig = {
     "custom-rules-filename": null,
@@ -188,4 +189,31 @@ describe("[RULE] pragma-on-top: Fixes", function() {
         done();
     });
 
+    it("should move an existing experimental pragma statement to top of file (above all code) when fix is enabled", done => {
+        const config = {
+            "rules": {
+                "pragma-on-top": "error"
+            }
+        };
+
+        const unfixedCode = `pragma solidity ^0.4.0;${EOL}contract Foo {}${EOL}pragma experimental \"^0.5.0\";`,
+            fixedCode = `pragma solidity ^0.4.0;${EOL}pragma experimental \"^0.5.0\";${EOL}contract Foo {}${EOL}`;
+
+        let fixed = Solium.lintAndFix(unfixedCode, config);
+
+        fixed.should.be.type("object");
+        fixed.should.have.ownProperty("fixedSourceCode");
+        fixed.should.have.ownProperty("errorMessages");
+        fixed.should.have.ownProperty("fixesApplied");
+
+        fixed.fixedSourceCode.should.equal(fixedCode);
+        fixed.errorMessages.should.be.Array();
+        fixed.errorMessages.should.be.empty();
+        fixed.fixesApplied.should.be.Array();
+        fixed.fixesApplied.should.have.size(1);
+
+        Solium.reset();
+        done();
+    });
+
 });