-Zfuel is incompatible with incremental compilation

Author: tmiasko

compiler/rustc_session/src/config.rs

@@ -2640,6 +2640,10 @@ pub fn build_session_options(
         handler.early_error("optimization fuel is incompatible with multiple threads");
     }
 
+    if unstable_opts.fuel.is_some() && cg.incremental.is_some() {
+        handler.early_error("optimization fuel is incompatible with incremental compilation");
+    }
+
     let incremental = cg.incremental.as_ref().map(PathBuf::from);
 
     let assert_incr_state = parse_assert_incr_state(handler, &unstable_opts.assert_incr_state);

tests/ui/invalid-compile-flags/fuel.incremental.stderr

@@ -0,0 +1,2 @@
+error: optimization fuel is incompatible with incremental compilation
+

tests/ui/invalid-compile-flags/fuel.rs

@@ -0,0 +1,10 @@
+// revisions: incremental threads
+//
+// [threads] compile-flags: -Zfuel=a=1 -Zthreads=2
+// [threads] error-pattern:optimization fuel is incompatible with multiple threads
+//
+// [incremental] incremental
+// [incremental] compile-flags: -Zfuel=a=1
+// [incremental] error-pattern:optimization fuel is incompatible with incremental compilation
+
+fn main() {}

tests/ui/invalid-compile-flags/fuel.threads.stderr

@@ -0,0 +1,2 @@
+error: optimization fuel is incompatible with multiple threads
+