fix catch variable reference in IE8 (#1587)

`AST_Scope.def_variable()` will overwrite `AST_Symbol.thedef`, so save a copy before calling.

fixes #1586

1 files changed, 36 insertions, 0 deletions

diff --git a/test/compress/screw-ie8.js b/test/compress/screw-ie8.js
index 36eb4d3a..4fbb95c8 100644
--- a/test/compress/screw-ie8.js
+++ b/test/compress/screw-ie8.js
@@ -182,3 +182,39 @@ reduce_vars: {
         }
     }
 }
+
+issue_1586_1: {
+    options = {
+        screw_ie8: false,
+    }
+    mangle = {
+        screw_ie8: false,
+    }
+    input: {
+        function f() {
+            try {
+            } catch (err) {
+                console.log(err.message);
+            }
+        }
+    }
+    expect_exact: "function f(){try{}catch(c){console.log(c.message)}}"
+}
+
+issue_1586_2: {
+    options = {
+        screw_ie8: true,
+    }
+    mangle = {
+        screw_ie8: true,
+    }
+    input: {
+        function f() {
+            try {
+            } catch (err) {
+                console.log(err.message);
+            }
+        }
+    }
+    expect_exact: "function f(){try{}catch(c){console.log(c.message)}}"
+}