Merge pull request #1020 from fitzgen/move-by-value-debug-asserts

Only emit JS glue assertions for move arguments in debug mode
rustwasm · Nov 8, 2018 · 227e836 · 227e836
2 parents d646b29 + 75c18f0
commit 227e836
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Showing 2 changed files with 19 additions and 7 deletions.
diff --git a/crates/cli-support/src/js/js2rust.rs b/crates/cli-support/src/js/js2rust.rs
@@ -85,7 +85,7 @@ impl<'a, 'b> Js2Rust<'a, 'b> {
             if self.cx.config.debug {
                 self.prelude(
                     "if (this.ptr === 0) {
-                        throw new Error('Attempt to use a moved value');
+                         throw new Error('Attempt to use a moved value');
                     }",
                 );
             }
@@ -330,14 +330,26 @@ impl<'a, 'b> Js2Rust<'a, 'b> {
                 self.prelude(&format!(
                     "\
                     const ptr{i} = {arg}.ptr;\n\
-                    if (ptr{i} === 0) {{
-                        throw new Error('Attempt to use a moved value');
-                    }}
-                    {arg}.ptr = 0;\n\
-                ",
+                    ",
                     i = i,
                     arg = name
                 ));
+                if self.cx.config.debug {
+                    self.prelude(&format!(
+                        "\
+                        if (ptr{i} === 0) {{
+                            throw new Error('Attempt to use a moved value');
+                        }}
+                        ",
+                        i = i,
+                    ));
+                }
+                self.prelude(&format!(
+                    "\
+                    {arg}.ptr = 0;\n\
+                    ",
+                    arg = name
+                ));
                 self.rust_arguments.push(format!("ptr{}", i));
             }
             return Ok(self);

diff --git a/tests/wasm/classes.js b/tests/wasm/classes.js
@@ -124,7 +124,7 @@ exports.js_readonly_fields = () => {
 
 exports.js_double_consume = () => {
     const r = new wasm.DoubleConsume();
-    assert.throws(() => r.consume(r), /Attempt to use a moved value/);
+    assert.throws(() => r.consume(r));
 };