From e23f90e41c177552aa7e1bde98c6ba1b7acb9d4f Mon Sep 17 00:00:00 2001
From: Leonid Logvinov <logvinov.leon@gmail.com>
Date: Wed, 30 Jan 2019 13:31:01 +0100
Subject: Fix the cannot read property range of null bug

---
 packages/sol-tracing-utils/CHANGELOG.json     | 4 ++++
 packages/sol-tracing-utils/src/ast_visitor.ts | 4 +++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/packages/sol-tracing-utils/CHANGELOG.json b/packages/sol-tracing-utils/CHANGELOG.json
index 16a12ca63..024e896da 100644
--- a/packages/sol-tracing-utils/CHANGELOG.json
+++ b/packages/sol-tracing-utils/CHANGELOG.json
@@ -17,6 +17,10 @@
             {
                 "note": "Print resasonable error message on bytecode collision",
                 "pr": 1535
+            },
+            {
+                "note": "Fix the bug in `ASTVisitor` causing the 'cannot read property `range` of `null`' error",
+                "pr": 1557
             }
         ]
     },
diff --git a/packages/sol-tracing-utils/src/ast_visitor.ts b/packages/sol-tracing-utils/src/ast_visitor.ts
index 1ac9cd1de..27f19378b 100644
--- a/packages/sol-tracing-utils/src/ast_visitor.ts
+++ b/packages/sol-tracing-utils/src/ast_visitor.ts
@@ -89,7 +89,9 @@ export class ASTVisitor {
         this._visitStatement(ast);
     }
     public ExpressionStatement(ast: Parser.ExpressionStatement): void {
-        this._visitStatement(ast.expression);
+        if (!_.isNull(ast.expression)) {
+            this._visitStatement(ast.expression);
+        }
     }
     public InlineAssemblyStatement(ast: Parser.InlineAssemblyStatement): void {
         this._visitStatement(ast);
-- 
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