Merge pull request #1484 from ethereum/erc-module-location

remix-analyzer/src/solidity-analyzer/modules/erc20Decimals.ts

@@ -29,15 +29,24 @@ export default class erc20Decimals implements AnalyzerModule {
                                                               (f.returns.length === 1 && (f.returns[0].type !== 'uint8' || f.node.visibility !== 'public'))
                                                             )
                                                     )
-
-        if (decimalsVar.length > 0 || decimalsFun.length > 0) {
+        if (decimalsVar.length > 0) {
+          for (const node of decimalsVar) {
+            warnings.push({
+              warning: `ERC20 contract's 'decimals' variable should be 'uint8' type`,
+              location: node.src,
+              more: ' https://eips.ethereum.org/EIPS/eip-20'
+            })
+          }
+        } else if (decimalsFun.length > 0) {
+          for (const fn of decimalsFun) {
             warnings.push({
-            warning: 'ERC20 Contracts decimals function should have uint8 as return type',
-            location: null,
+              warning: `ERC20 contract's 'decimals' function should have 'uint8' as return type`,
+              location: fn.node.src,
               more: ' https://eips.ethereum.org/EIPS/eip-20'
             })
           }
         }
+      }
     })
     return warnings
   }

remix-analyzer/src/types.ts

@@ -24,6 +24,15 @@ export interface ReportObj {
     more?: string
 }
 
+// Regarding location, she source mappings inside the AST use the following notation:
+
+// s:l:f
+
+// Where, 
+//  s is the byte-offset to the start of the range in the source file, 
+//  l is the length of the source range in bytes and 
+//  f is the source index mentioned above.
+
 export interface AnalysisReportObj extends ReportObj {
   error? : string
 }