3 files changed, 15 insertions, 1 deletions
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriter.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriter.java
index 43442d2..19b194f 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriter.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriter.java
@@ -405,6 +405,7 @@ public class RustWriter implements AutoCloseable {
     private void writePrefixExpression(RustPrefixExpression prefixExpression) throws IOException {
         this.writer.write(switch (prefixExpression.operator()) {
             case BORROW -> "&";
+            case BORROW_MUTABLE -> "&mut ";
         });
         this.writeExpression(prefixExpression.operand());
     }
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustPrefixOperator.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustPrefixOperator.java
index d5c69c1..f2c0aa8 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustPrefixOperator.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustPrefixOperator.java
@@ -6,7 +6,8 @@ package org.zwobble.hobgoblin.compiler.output.lang.rust.ast;
 // Custom area end: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixOperator imports
 
 public enum RustPrefixOperator {
-    BORROW
+    BORROW,
+    BORROW_MUTABLE
 
     // Custom area start: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixOperator body
     // Custom area end: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixOperator body
diff --git a/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriterTests.java b/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriterTests.java
index aa6c887..e4cee1e 100644
--- a/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriterTests.java
+++ b/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriterTests.java
@@ -549,6 +549,18 @@ public class RustWriterTests {
         assertThat(string, equalTo("&x"));
     }
 
+    @Test
+    public void borrowMutableExpression() throws IOException {
+        var rust = RustPrefixExpression.arbitrary()
+            .withOperator(RustPrefixOperator.BORROW_MUTABLE)
+            .withOperand(RustPath.of("x"))
+            .build();
+
+        var string = write(writer -> writer.writeExpression(rust));
+
+        assertThat(string, equalTo("&mut x"));
+    }
+
     // === Struct expressions ===
 
     @Test