diff --git a/etc/config/rust.amazon.properties b/etc/config/rust.amazon.properties
index 5e007d6966f..63631a2f8ee 100644
--- a/etc/config/rust.amazon.properties
+++ b/etc/config/rust.amazon.properties
@@ -161,6 +161,8 @@ compiler.gccrs-snapshot.notification=Rust GCC Frontend - Very early snapshot
 group.rustgcc.compilerType=gccrs
 group.rustgcc.compilers=gccrs-snapshot
 group.rustgcc.groupName=Rust-GCC
+## needed, until its support is on-par with rustc (at some arbitrary version).
+group.rustgcc.options=-frust-incomplete-and-experimental-compiler-do-not-use
 
 group.rustccggcc.compilers=rustccggcc-master
 compiler.rustccggcc-master.exe=/opt/compiler-explorer/rustc-cg-gcc-master/bin/rustc