Fix invoking cargo without consulting CARGO or standard installation paths

Cargo.lock

@@ -1364,6 +1364,7 @@ dependencies = [
  "ra_syntax",
  "ra_text_edit",
  "ra_tt",
+ "ra_toolchain",
  "ra_vfs",
  "rand",
  "relative-path",

crates/rust-analyzer/Cargo.toml

@@ -48,6 +48,7 @@ hir = { path = "../ra_hir", package = "ra_hir" }
 hir_def = { path = "../ra_hir_def", package = "ra_hir_def" }
 hir_ty = { path = "../ra_hir_ty", package = "ra_hir_ty" }
 ra_proc_macro_srv = { path = "../ra_proc_macro_srv" }
+ra_toolchain = { path = "../ra_toolchain" }
 
 [target.'cfg(windows)'.dependencies]
 winapi = "0.3.8"

crates/rust-analyzer/src/main_loop/handlers.rs

@@ -40,6 +40,7 @@ use crate::{
     world::WorldSnapshot,
     LspError, Result,
 };
+use anyhow::Context;
 
 pub fn handle_analyzer_status(world: WorldSnapshot, _: ()) -> Result<String> {
     let _p = profile("handle_analyzer_status");
@@ -982,10 +983,15 @@ fn to_lsp_runnable(
             target.map_or_else(|| "run binary".to_string(), |t| format!("run {}", t))
         }
     };
+    let cargo_path = ra_toolchain::cargo()
+        .to_str()
+        .context("Path to cargo executable contains invalid UTF8 characters")?
+        .to_owned();
+
     Ok(lsp_ext::Runnable {
         range: to_proto::range(&line_index, runnable.range),
         label,
-        bin: "cargo".to_string(),
+        bin: cargo_path,
         args,
         extra_args,
         env: {

editors/code/src/cargo.ts

@@ -126,8 +126,8 @@ export class Cargo {
     }
 }
 
-// Mirrors `ra_env::get_path_for_executable` implementation
-function getCargoPathOrFail(): string {
+// Mirrors `ra_toolchain::cargo()` implementation
+export function getCargoPathOrFail(): string {
     const envVar = process.env.CARGO;
     const executableName = "cargo";
 

editors/code/src/tasks.ts

@@ -1,4 +1,5 @@
 import * as vscode from 'vscode';
+import { getCargoPathOrFail } from "./cargo";
 
 // This ends up as the `type` key in tasks.json. RLS also uses `cargo` and
 // our configuration should be compatible with it so use the same key.
@@ -24,6 +25,8 @@ class CargoTaskProvider implements vscode.TaskProvider {
         // set of tasks that always exist. These tasks cannot be removed in
         // tasks.json - only tweaked.
 
+        const cargoPath = getCargoPathOrFail();
+
         return [
             { command: 'build', group: vscode.TaskGroup.Build },
             { command: 'check', group: vscode.TaskGroup.Build },
@@ -46,7 +49,7 @@ class CargoTaskProvider implements vscode.TaskProvider {
                     `cargo ${command}`,
                     'rust',
                     // What to do when this command is executed.
-                    new vscode.ShellExecution('cargo', [command]),
+                    new vscode.ShellExecution(cargoPath, [command]),
                     // Problem matchers.
                     ['$rustc'],
                 );