Set debug_assertions and miri cfgs as config defaults, allowing them to be overwritten

crates/project-model/src/env.rs

@@ -1,3 +1,4 @@
+//! Cargo-like environment variables injection.
 use base_db::Env;
 use rustc_hash::FxHashMap;
 use toolchain::Tool;

crates/project-model/src/rustc_cfg.rs

@@ -32,9 +32,6 @@ pub(crate) fn get(
         }
     }
 
-    // Add miri cfg, which is useful for mir eval in stdlib
-    res.push(CfgFlag::Atom("miri".into()));
-
     let rustc_cfgs = get_rust_cfgs(target, extra_env, config);
 
     let rustc_cfgs = match rustc_cfgs {

crates/project-model/src/workspace.rs

@@ -1454,8 +1454,14 @@ fn sysroot_to_crate_graph(
                 None,
                 rustc_cfg,
                 &CfgOverrides {
-                    global: CfgDiff::new(vec![CfgAtom::Flag("debug_assertions".into())], vec![])
-                        .unwrap(),
+                    global: CfgDiff::new(
+                        vec![
+                            CfgAtom::Flag("debug_assertions".into()),
+                            CfgAtom::Flag("miri".into()),
+                        ],
+                        vec![],
+                    )
+                    .unwrap(),
                     ..Default::default()
                 },
                 &WorkspaceBuildScripts::default(),
@@ -1519,6 +1525,7 @@ fn sysroot_to_crate_graph(
                 let mut cfg_options = CfgOptions::default();
                 cfg_options.extend(rustc_cfg);
                 cfg_options.insert_atom("debug_assertions".into());
+                cfg_options.insert_atom("miri".into());
                 cfg_options
             });
             let sysroot_crates: FxHashMap<SysrootCrate, CrateId> = stitched