Pass cargo.target to rustc

crates/ra_project_model/src/lib.rs

@@ -543,7 +543,7 @@ pub fn workspace_root_for(&self, path: &Path) -> Option<&Path> {
     }
 }
 
-pub fn get_rustc_cfg_options() -> CfgOptions {
+pub fn get_rustc_cfg_options(target: Option<&String>) -> CfgOptions {
     let mut cfg_options = CfgOptions::default();
 
     // Some nightly-only cfgs, which are required for stdlib
@@ -558,10 +558,18 @@ pub fn get_rustc_cfg_options() -> CfgOptions {
 
     match (|| -> Result<String> {
         // `cfg(test)` and `cfg(debug_assertion)` are handled outside, so we suppress them here.
-        let output = Command::new("rustc")
-            .args(&["--print", "cfg", "-O"])
-            .output()
-            .context("Failed to get output from rustc --print cfg -O")?;
+        let output = if let Some(target) = target {
+            Command::new("rustc")
+                .args(&["--print", "cfg", "-O", "--target", target.as_str()])
+                .output()
+                .context("Failed to get output from rustc --print cfg -O")?
+        } else {
+            Command::new("rustc")
+                .args(&["--print", "cfg", "-O"])
+                .output()
+                .context("Failed to get output from rustc --print cfg -O")?
+        };
+
         if !output.status.success() {
             bail!(
                 "rustc --print cfg -O exited with exit code ({})",

crates/rust-analyzer/src/cli/load_cargo.rs

@@ -149,7 +149,7 @@ pub(crate) fn load(
 
     // FIXME: cfg options?
     let default_cfg_options = {
-        let mut opts = get_rustc_cfg_options();
+        let mut opts = get_rustc_cfg_options(None);
         opts.insert_atom("test".into());
         opts.insert_atom("debug_assertion".into());
         opts

crates/rust-analyzer/src/world.rs

@@ -131,7 +131,7 @@ pub fn new(
 
         // FIXME: Read default cfgs from config
         let default_cfg_options = {
-            let mut opts = get_rustc_cfg_options();
+            let mut opts = get_rustc_cfg_options(config.cargo.target.as_ref());
             opts.insert_atom("test".into());
             opts.insert_atom("debug_assertion".into());
             opts