6 files changed, 222 insertions, 98 deletions

diff --git a/editors/code/package-lock.json b/editors/code/package-lock.json
index e11cffd68..55ba5351d 100644
--- a/editors/code/package-lock.json
+++ b/editors/code/package-lock.json
@@ -25,25 +25,27 @@
             }
         },
         "@rollup/plugin-commonjs": {
-            "version": "11.0.2",
-            "resolved": "https://registry.npmjs.org/@rollup/plugin-commonjs/-/plugin-commonjs-11.0.2.tgz",
-            "integrity": "sha512-MPYGZr0qdbV5zZj8/2AuomVpnRVXRU5XKXb3HVniwRoRCreGlf5kOE081isNWeiLIi6IYkwTX9zE0/c7V8g81g==",
+            "version": "11.1.0",
+            "resolved": "https://registry.npmjs.org/@rollup/plugin-commonjs/-/plugin-commonjs-11.1.0.tgz",
+            "integrity": "sha512-Ycr12N3ZPN96Fw2STurD21jMqzKwL9QuFhms3SD7KKRK7oaXUsBU9Zt0jL/rOPHiPYisI21/rXGO3jr9BnLHUA==",
             "dev": true,
             "requires": {
-                "@rollup/pluginutils": "^3.0.0",
+                "@rollup/pluginutils": "^3.0.8",
+                "commondir": "^1.0.1",
                 "estree-walker": "^1.0.1",
+                "glob": "^7.1.2",
                 "is-reference": "^1.1.2",
                 "magic-string": "^0.25.2",
                 "resolve": "^1.11.0"
             }
         },
         "@rollup/plugin-node-resolve": {
-            "version": "7.1.1",
-            "resolved": "https://registry.npmjs.org/@rollup/plugin-node-resolve/-/plugin-node-resolve-7.1.1.tgz",
-            "integrity": "sha512-14ddhD7TnemeHE97a4rLOhobfYvUVcaYuqTnL8Ti7Jxi9V9Jr5LY7Gko4HZ5k4h4vqQM0gBQt6tsp9xXW94WPA==",
+            "version": "7.1.3",
+            "resolved": "https://registry.npmjs.org/@rollup/plugin-node-resolve/-/plugin-node-resolve-7.1.3.tgz",
+            "integrity": "sha512-RxtSL3XmdTAE2byxekYLnx+98kEUOrPHF/KRVjLH+DEIHy6kjIw7YINQzn+NXiH/NTrQLAwYs0GWB+csWygA9Q==",
             "dev": true,
             "requires": {
-                "@rollup/pluginutils": "^3.0.6",
+                "@rollup/pluginutils": "^3.0.8",
                 "@types/resolve": "0.0.8",
                 "builtin-modules": "^3.1.0",
                 "is-module": "^1.0.0",
@@ -51,12 +53,14 @@
             }
         },
         "@rollup/pluginutils": {
-            "version": "3.0.8",
-            "resolved": "https://registry.npmjs.org/@rollup/pluginutils/-/pluginutils-3.0.8.tgz",
-            "integrity": "sha512-rYGeAc4sxcZ+kPG/Tw4/fwJODC3IXHYDH4qusdN/b6aLw5LPUbzpecYbEJh4sVQGPFJxd2dBU4kc1H3oy9/bnw==",
+            "version": "3.0.9",
+            "resolved": "https://registry.npmjs.org/@rollup/pluginutils/-/pluginutils-3.0.9.tgz",
+            "integrity": "sha512-TLZavlfPAZYI7v33wQh4mTP6zojne14yok3DNSLcjoG/Hirxfkonn6icP5rrNWRn8nZsirJBFFpijVOJzkUHDg==",
             "dev": true,
             "requires": {
-                "estree-walker": "^1.0.1"
+                "@types/estree": "0.0.39",
+                "estree-walker": "^1.0.1",
+                "micromatch": "^4.0.2"
             }
         },
         "@types/color-name": {
@@ -84,15 +88,15 @@
             "dev": true
         },
         "@types/node": {
-            "version": "12.12.34",
-            "resolved": "https://registry.npmjs.org/@types/node/-/node-12.12.34.tgz",
-            "integrity": "sha512-BneGN0J9ke24lBRn44hVHNeDlrXRYF+VRp0HbSUNnEZahXGAysHZIqnf/hER6aabdBgzM4YOV4jrR8gj4Zfi0g==",
+            "version": "12.12.37",
+            "resolved": "https://registry.npmjs.org/@types/node/-/node-12.12.37.tgz",
+            "integrity": "sha512-4mXKoDptrXAwZErQHrLzpe0FN/0Wmf5JRniSVIdwUrtDf9wnmEV1teCNLBo/TwuXhkK/bVegoEn/wmb+x0AuPg==",
             "dev": true
         },
         "@types/node-fetch": {
-            "version": "2.5.5",
-            "resolved": "https://registry.npmjs.org/@types/node-fetch/-/node-fetch-2.5.5.tgz",
-            "integrity": "sha512-IWwjsyYjGw+em3xTvWVQi5MgYKbRs0du57klfTaZkv/B24AEQ/p/IopNeqIYNy3EsfHOpg8ieQSDomPcsYMHpA==",
+            "version": "2.5.6",
+            "resolved": "https://registry.npmjs.org/@types/node-fetch/-/node-fetch-2.5.6.tgz",
+            "integrity": "sha512-2w0NTwMWF1d3NJMK0Uiq2UNN8htVCyOWOD0jIPjPgC5Ph/YP4dVhs9YxxcMcuLuwAslz0dVEcZQUaqkLs3IzOQ==",
             "dev": true,
             "requires": {
                 "@types/node": "*",
@@ -115,25 +119,25 @@
             "dev": true
         },
         "@typescript-eslint/eslint-plugin": {
-            "version": "2.27.0",
-            "resolved": "https://registry.npmjs.org/@typescript-eslint/eslint-plugin/-/eslint-plugin-2.27.0.tgz",
-            "integrity": "sha512-/my+vVHRN7zYgcp0n4z5A6HAK7bvKGBiswaM5zIlOQczsxj/aiD7RcgD+dvVFuwFaGh5+kM7XA6Q6PN0bvb1tw==",
+            "version": "2.29.0",
+            "resolved": "https://registry.npmjs.org/@typescript-eslint/eslint-plugin/-/eslint-plugin-2.29.0.tgz",
+            "integrity": "sha512-X/YAY7azKirENm4QRpT7OVmzok02cSkqeIcLmdz6gXUQG4Hk0Fi9oBAynSAyNXeGdMRuZvjBa0c1Lu0dn/u6VA==",
             "dev": true,
             "requires": {
-                "@typescript-eslint/experimental-utils": "2.27.0",
+                "@typescript-eslint/experimental-utils": "2.29.0",
                 "functional-red-black-tree": "^1.0.1",
                 "regexpp": "^3.0.0",
                 "tsutils": "^3.17.1"
             }
         },
         "@typescript-eslint/experimental-utils": {
-            "version": "2.27.0",
-            "resolved": "https://registry.npmjs.org/@typescript-eslint/experimental-utils/-/experimental-utils-2.27.0.tgz",
-            "integrity": "sha512-vOsYzjwJlY6E0NJRXPTeCGqjv5OHgRU1kzxHKWJVPjDYGbPgLudBXjIlc+OD1hDBZ4l1DLbOc5VjofKahsu9Jw==",
+            "version": "2.29.0",
+            "resolved": "https://registry.npmjs.org/@typescript-eslint/experimental-utils/-/experimental-utils-2.29.0.tgz",
+            "integrity": "sha512-H/6VJr6eWYstyqjWXBP2Nn1hQJyvJoFdDtsHxGiD+lEP7piGnGpb/ZQd+z1ZSB1F7dN+WsxUDh8+S4LwI+f3jw==",
             "dev": true,
             "requires": {
                 "@types/json-schema": "^7.0.3",
-                "@typescript-eslint/typescript-estree": "2.27.0",
+                "@typescript-eslint/typescript-estree": "2.29.0",
                 "eslint-scope": "^5.0.0",
                 "eslint-utils": "^2.0.0"
             },
@@ -150,21 +154,21 @@
             }
         },
         "@typescript-eslint/parser": {
-            "version": "2.27.0",
-            "resolved": "https://registry.npmjs.org/@typescript-eslint/parser/-/parser-2.27.0.tgz",
-            "integrity": "sha512-HFUXZY+EdwrJXZo31DW4IS1ujQW3krzlRjBrFRrJcMDh0zCu107/nRfhk/uBasO8m0NVDbBF5WZKcIUMRO7vPg==",
+            "version": "2.29.0",
+            "resolved": "https://registry.npmjs.org/@typescript-eslint/parser/-/parser-2.29.0.tgz",
+            "integrity": "sha512-H78M+jcu5Tf6m/5N8iiFblUUv+HJDguMSdFfzwa6vSg9lKR8Mk9BsgeSjO8l2EshKnJKcbv0e8IDDOvSNjl0EA==",
             "dev": true,
             "requires": {
                 "@types/eslint-visitor-keys": "^1.0.0",
-                "@typescript-eslint/experimental-utils": "2.27.0",
-                "@typescript-eslint/typescript-estree": "2.27.0",
+                "@typescript-eslint/experimental-utils": "2.29.0",
+                "@typescript-eslint/typescript-estree": "2.29.0",
                 "eslint-visitor-keys": "^1.1.0"
             }
         },
         "@typescript-eslint/typescript-estree": {
-            "version": "2.27.0",
-            "resolved": "https://registry.npmjs.org/@typescript-eslint/typescript-estree/-/typescript-estree-2.27.0.tgz",
-            "integrity": "sha512-t2miCCJIb/FU8yArjAvxllxbTiyNqaXJag7UOpB5DVoM3+xnjeOngtqlJkLRnMtzaRcJhe3CIR9RmL40omubhg==",
+            "version": "2.29.0",
+            "resolved": "https://registry.npmjs.org/@typescript-eslint/typescript-estree/-/typescript-estree-2.29.0.tgz",
+            "integrity": "sha512-3YGbtnWy4az16Egy5Fj5CckkVlpIh0MADtAQza+jiMADRSKkjdpzZp/5WuvwK/Qib3Z0HtzrDFeWanS99dNhnA==",
             "dev": true,
             "requires": {
                 "debug": "^4.1.1",
@@ -287,6 +291,15 @@
                 "concat-map": "0.0.1"
             }
         },
+        "braces": {
+            "version": "3.0.2",
+            "resolved": "https://registry.npmjs.org/braces/-/braces-3.0.2.tgz",
+            "integrity": "sha512-b8um+L1RzM3WDSzvhm6gIz1yfTbBt6YTlcEKAvsmqCZZFw46z626lVj9j1yEPW33H5H+lBQpZMP1k8l+78Ha0A==",
+            "dev": true,
+            "requires": {
+                "fill-range": "^7.0.1"
+            }
+        },
         "buffer-crc32": {
             "version": "0.2.13",
             "resolved": "https://registry.npmjs.org/buffer-crc32/-/buffer-crc32-0.2.13.tgz",
@@ -387,6 +400,12 @@
             "integrity": "sha512-aE2Y4MTFJ870NuB/+2z1cXBhSBBzRydVVjzhFC4gtenEhpnj15yu0qptWGJsO9YGrcPZ3ezX8AWb1VA391MKpQ==",
             "dev": true
         },
+        "commondir": {
+            "version": "1.0.1",
+            "resolved": "https://registry.npmjs.org/commondir/-/commondir-1.0.1.tgz",
+            "integrity": "sha1-3dgA2gxmEnOTzKWVDqloo6rxJTs=",
+            "dev": true
+        },
         "concat-map": {
             "version": "0.0.1",
             "resolved": "https://registry.npmjs.org/concat-map/-/concat-map-0.0.1.tgz",
@@ -728,6 +747,15 @@
                 "flat-cache": "^2.0.1"
             }
         },
+        "fill-range": {
+            "version": "7.0.1",
+            "resolved": "https://registry.npmjs.org/fill-range/-/fill-range-7.0.1.tgz",
+            "integrity": "sha512-qOo9F+dMUmC2Lcb4BbVvnKJxTPjCm+RRpe4gDuGrzkL7mEVl/djYSu2OdQ2Pa302N4oqkSg9ir6jaLWJ2USVpQ==",
+            "dev": true,
+            "requires": {
+                "to-regex-range": "^5.0.1"
+            }
+        },
         "flat-cache": {
             "version": "2.0.1",
             "resolved": "https://registry.npmjs.org/flat-cache/-/flat-cache-2.0.1.tgz",
@@ -763,9 +791,9 @@
             "dev": true
         },
         "fsevents": {
-            "version": "2.1.2",
-            "resolved": "https://registry.npmjs.org/fsevents/-/fsevents-2.1.2.tgz",
-            "integrity": "sha512-R4wDiBwZ0KzpgOWetKDug1FZcYhqYnUYKtfZYt4mD5SBz76q0KR4Q9o7GIPamsVPGmW3EYPPJ0dOOjvx32ldZA==",
+            "version": "2.1.3",
+            "resolved": "https://registry.npmjs.org/fsevents/-/fsevents-2.1.3.tgz",
+            "integrity": "sha512-Auw9a4AxqWpa9GUfj370BMPzzyncfBABW8Mab7BGWBYDj4Isgq+cDKtx0i6u9jcX9pQDnswsaaOTgTmA5pEjuQ==",
             "dev": true,
             "optional": true
         },
@@ -983,6 +1011,12 @@
             "integrity": "sha1-Mlj7afeMFNW4FdZkM2tM/7ZEFZE=",
             "dev": true
         },
+        "is-number": {
+            "version": "7.0.0",
+            "resolved": "https://registry.npmjs.org/is-number/-/is-number-7.0.0.tgz",
+            "integrity": "sha512-41Cifkg6e8TylSpdtTpeLVMqvSBEVzTttHvERD741+pnZ8ANv0004MRL43QKPDlK9cGvNp6NZWZUBlbGXYxxng==",
+            "dev": true
+        },
         "is-promise": {
             "version": "2.1.0",
             "resolved": "https://registry.npmjs.org/is-promise/-/is-promise-2.1.0.tgz",
@@ -1114,6 +1148,16 @@
             "integrity": "sha1-/oWy7HWlkDfyrf7BAP1sYBdhFS4=",
             "dev": true
         },
+        "micromatch": {
+            "version": "4.0.2",
+            "resolved": "https://registry.npmjs.org/micromatch/-/micromatch-4.0.2.tgz",
+            "integrity": "sha512-y7FpHSbMUMoyPbYUSzO6PaZ6FyRnQOpHuKwbo1G+Knck95XVU4QAiKdGEnj5wwoS7PlOgthX/09u5iFJ+aYf5Q==",
+            "dev": true,
+            "requires": {
+                "braces": "^3.0.1",
+                "picomatch": "^2.0.5"
+            }
+        },
         "mime": {
             "version": "1.6.0",
             "resolved": "https://registry.npmjs.org/mime/-/mime-1.6.0.tgz",
@@ -1322,6 +1366,12 @@
             "integrity": "sha1-elfrVQpng/kRUzH89GY9XI4AelA=",
             "dev": true
         },
+        "picomatch": {
+            "version": "2.2.2",
+            "resolved": "https://registry.npmjs.org/picomatch/-/picomatch-2.2.2.tgz",
+            "integrity": "sha512-q0M/9eZHzmr0AulXyPwNfZjtwZ/RBZlbN3K3CErVrk50T2ASYI7Bye0EvekFY3IP1Nt2DHu0re+V2ZHIpMkuWg==",
+            "dev": true
+        },
         "prelude-ls": {
             "version": "1.1.2",
             "resolved": "https://registry.npmjs.org/prelude-ls/-/prelude-ls-1.1.2.tgz",
@@ -1373,9 +1423,9 @@
             "dev": true
         },
         "resolve": {
-            "version": "1.15.1",
-            "resolved": "https://registry.npmjs.org/resolve/-/resolve-1.15.1.tgz",
-            "integrity": "sha512-84oo6ZTtoTUpjgNEr5SJyzQhzL72gaRodsSfyxC/AXRvwu0Yse9H8eF9IpGo7b8YetZhlI6v7ZQ6bKBFV/6S7w==",
+            "version": "1.16.1",
+            "resolved": "https://registry.npmjs.org/resolve/-/resolve-1.16.1.tgz",
+            "integrity": "sha512-rmAglCSqWWMrrBv/XM6sW0NuRFiKViw/W4d9EbC4pt+49H8JwHy+mcGmALTEg504AUDcLTvb1T2q3E9AnmY+ig==",
             "dev": true,
             "requires": {
                 "path-parse": "^1.0.6"
@@ -1407,9 +1457,9 @@
             }
         },
         "rollup": {
-            "version": "2.3.3",
-            "resolved": "https://registry.npmjs.org/rollup/-/rollup-2.3.3.tgz",
-            "integrity": "sha512-uJ9VNWk80mb4wDCSfd1AyHoSc9TrWbkZtnO6wbsMTp9muSWkT26Dvc99MX1yGCOTvUN1Skw/KpFzKdUDuZKTXA==",
+            "version": "2.7.1",
+            "resolved": "https://registry.npmjs.org/rollup/-/rollup-2.7.1.tgz",
+            "integrity": "sha512-c1FCjY8HK1nAq0bTZHaR72ZknpP7p0EjxbcVc6BcmtOosurK//P5jtwxX+f/4fgtbrjczqf0uvR+EdtxpriE8g==",
             "dev": true,
             "requires": {
                 "fsevents": "~2.1.2"
@@ -1629,6 +1679,15 @@
                 "os-tmpdir": "~1.0.2"
             }
         },
+        "to-regex-range": {
+            "version": "5.0.1",
+            "resolved": "https://registry.npmjs.org/to-regex-range/-/to-regex-range-5.0.1.tgz",
+            "integrity": "sha512-65P7iz6X5yEr1cwcgvQxbbIw7Uk3gOy5dIdtZ4rDveLqhrdJP+Li/Hx6tyK0NEb+2GCyneCMJiGqrADCSNk8sQ==",
+            "dev": true,
+            "requires": {
+                "is-number": "^7.0.0"
+            }
+        },
         "tslib": {
             "version": "1.11.1",
             "resolved": "https://registry.npmjs.org/tslib/-/tslib-1.11.1.tgz",
diff --git a/editors/code/package.json b/editors/code/package.json
index 5ce59e54a..b8aaa07d8 100644
--- a/editors/code/package.json
+++ b/editors/code/package.json
@@ -37,15 +37,15 @@
         "vscode-languageclient": "7.0.0-next.1"
     },
     "devDependencies": {
-        "@rollup/plugin-commonjs": "^11.0.2",
-        "@rollup/plugin-node-resolve": "^7.1.1",
-        "@types/node": "^12.12.34",
-        "@types/node-fetch": "^2.5.5",
+        "@rollup/plugin-commonjs": "^11.1.0",
+        "@rollup/plugin-node-resolve": "^7.1.3",
+        "@types/node": "^12.12.37",
+        "@types/node-fetch": "^2.5.6",
         "@types/vscode": "^1.44.0",
-        "@typescript-eslint/eslint-plugin": "^2.27.0",
-        "@typescript-eslint/parser": "^2.27.0",
+        "@typescript-eslint/eslint-plugin": "^2.29.0",
+        "@typescript-eslint/parser": "^2.29.0",
         "eslint": "^6.8.0",
-        "rollup": "^2.3.3",
+        "rollup": "^2.7.1",
         "tslib": "^1.11.1",
         "typescript": "^3.8.3",
         "typescript-formatter": "^7.2.2",
@@ -166,11 +166,6 @@
                 "command": "rust-analyzer.joinLines",
                 "key": "ctrl+shift+j",
                 "when": "editorTextFocus && editorLangId == rust"
-            },
-            {
-                "command": "rust-analyzer.onEnter",
-                "key": "enter",
-                "when": "editorTextFocus && !suggestWidgetVisible && editorLangId == rust && !vim.active || vim.mode == 'Insert' && editorTextFocus && !suggestWidgetVisible && editorLangId == rust"
             }
         ],
         "configuration": {
@@ -389,7 +384,7 @@
                     "type": "boolean",
                     "default": false
                 },
-                "rust-analyzer.procMacro.enabled": {
+                "rust-analyzer.procMacro.enable": {
                     "description": "Enable Proc macro support, cargo.loadOutDirsFromCheck must be enabled.",
                     "type": "boolean",
                     "default": false
@@ -517,6 +512,10 @@
                 "id": "union",
                 "description": "Style for C-style untagged unions",
                 "superType": "type"
+            },
+            {
+                "id": "unresolvedReference",
+                "description": "Style for names which can not be resolved due to compilation errors"
             }
         ],
         "semanticTokenModifiers": [
diff --git a/editors/code/ra_syntax_tree.tmGrammar.json b/editors/code/ra_syntax_tree.tmGrammar.json
index 0d72a3e36..431d414f6 100644
--- a/editors/code/ra_syntax_tree.tmGrammar.json
+++ b/editors/code/ra_syntax_tree.tmGrammar.json
@@ -9,7 +9,7 @@
     ],
     "repository": {
         "node_type": {
-            "match": "^\\s*([A-Z_]+?)@",
+            "match": "^\\s*([A-Z_][A-Z_0-9]*?)@",
             "captures": {
                 "1": {
                     "name": "entity.name.class"
diff --git a/editors/code/src/commands/syntax_tree.ts b/editors/code/src/commands/syntax_tree.ts
index b7a397414..cfcf47b2f 100644
--- a/editors/code/src/commands/syntax_tree.ts
+++ b/editors/code/src/commands/syntax_tree.ts
@@ -198,7 +198,7 @@ class AstInspector implements vscode.HoverProvider, vscode.DefinitionProvider, D
         return new vscode.Hover(["```rust\n" + rustSourceCode + "\n```"], astFileRange);
     }
 
-    private findAstNodeRange(astLine: vscode.TextLine) {
+    private findAstNodeRange(astLine: vscode.TextLine): vscode.Range {
         const lineOffset = astLine.range.start;
         const begin = lineOffset.translate(undefined, astLine.firstNonWhitespaceCharacterIndex);
         const end = lineOffset.translate(undefined, astLine.text.trimEnd().length);
@@ -209,10 +209,43 @@ class AstInspector implements vscode.HoverProvider, vscode.DefinitionProvider, D
         const parsedRange = /\[(\d+); (\d+)\)/.exec(astLine);
         if (!parsedRange) return;
 
-        const [begin, end] = parsedRange.slice(1).map(off => doc.positionAt(+off));
+        const [begin, end] = parsedRange
+            .slice(1)
+            .map(off => this.positionAt(doc, +off));
 
         return new vscode.Range(begin, end);
     }
+
+    // Memoize the last value, otherwise the CPU is at 100% single core
+    // with quadratic lookups when we build rust2Ast cache
+    cache?: { doc: vscode.TextDocument; offset: number; line: number };
+
+    positionAt(doc: vscode.TextDocument, targetOffset: number): vscode.Position {
+        if (doc.eol === vscode.EndOfLine.LF) {
+            return doc.positionAt(targetOffset);
+        }
+
+        // Shitty workaround for crlf line endings
+        // We are still in this prehistoric era of carriage returns here...
+
+        let line = 0;
+        let offset = 0;
+
+        const cache = this.cache;
+        if (cache?.doc === doc && cache.offset <= targetOffset) {
+            ({ line, offset } = cache);
+        }
+
+        while (true) {
+            const lineLenWithLf = doc.lineAt(line).text.length + 1;
+            if (offset + lineLenWithLf > targetOffset) {
+                this.cache = { doc, offset, line };
+                return doc.positionAt(targetOffset + line);
+            }
+            offset += lineLenWithLf;
+            line += 1;
+        }
+    }
 }
 
 class Lazy<T> {
diff --git a/editors/code/src/source_change.ts b/editors/code/src/source_change.ts
index 399a150c6..af8f1df51 100644
--- a/editors/code/src/source_change.ts
+++ b/editors/code/src/source_change.ts
@@ -37,11 +37,13 @@ export async function applySourceChange(ctx: Ctx, change: ra.SourceChange) {
             toReveal.position,
         );
         const editor = vscode.window.activeTextEditor;
-        if (!editor || editor.document.uri.toString() !== uri.toString()) {
+        if (!editor || !editor.selection.isEmpty) {
             return;
         }
-        if (!editor.selection.isEmpty) {
-            return;
+
+        if (editor.document.uri !== uri) {
+            const doc = await vscode.workspace.openTextDocument(uri);
+            await vscode.window.showTextDocument(doc);
         }
         editor.selection = new vscode.Selection(position, position);
         editor.revealRange(
diff --git a/editors/code/src/tasks.ts b/editors/code/src/tasks.ts
index fa1c4a951..1366c76d6 100644
--- a/editors/code/src/tasks.ts
+++ b/editors/code/src/tasks.ts
@@ -4,49 +4,80 @@ import * as vscode from 'vscode';
 // our configuration should be compatible with it so use the same key.
 const TASK_TYPE = 'cargo';
 
-export function activateTaskProvider(target: vscode.WorkspaceFolder): vscode.Disposable {
-    const provider: vscode.TaskProvider = {
+interface CargoTaskDefinition extends vscode.TaskDefinition {
+    command?: string;
+    args?: string[];
+    cwd?: string;
+    env?: { [key: string]: string };
+}
+
+class CargoTaskProvider implements vscode.TaskProvider {
+    private readonly target: vscode.WorkspaceFolder;
+
+    constructor(target: vscode.WorkspaceFolder) {
+        this.target = target;
+    }
+
+    provideTasks(): vscode.Task[] {
         // Detect Rust tasks. Currently we do not do any actual detection
         // of tasks (e.g. aliases in .cargo/config) and just return a fixed
         // set of tasks that always exist. These tasks cannot be removed in
         // tasks.json - only tweaked.
-        provideTasks: () => getStandardCargoTasks(target),
 
-        // We don't need to implement this.
-        resolveTask: () => undefined,
-    };
+        return [
+            { command: 'build', group: vscode.TaskGroup.Build },
+            { command: 'check', group: vscode.TaskGroup.Build },
+            { command: 'test', group: vscode.TaskGroup.Test },
+            { command: 'clean', group: vscode.TaskGroup.Clean },
+            { command: 'run', group: undefined },
+        ]
+            .map(({ command, group }) => {
+                const vscodeTask = new vscode.Task(
+                    // The contents of this object end up in the tasks.json entries.
+                    {
+                        type: TASK_TYPE,
+                        command,
+                    },
+                    // The scope of the task - workspace or specific folder (global
+                    // is not supported).
+                    this.target,
+                    // The task name, and task source. These are shown in the UI as
+                    // `${source}: ${name}`, e.g. `rust: cargo build`.
+                    `cargo ${command}`,
+                    'rust',
+                    // What to do when this command is executed.
+                    new vscode.ShellExecution('cargo', [command]),
+                    // Problem matchers.
+                    ['$rustc'],
+                );
+                vscodeTask.group = group;
+                return vscodeTask;
+            });
+    }
 
-    return vscode.tasks.registerTaskProvider(TASK_TYPE, provider);
-}
+    resolveTask(task: vscode.Task): vscode.Task | undefined {
+        // VSCode calls this for every cargo task in the user's tasks.json,
+        // we need to inform VSCode how to execute that command by creating
+        // a ShellExecution for it.
 
-function getStandardCargoTasks(target: vscode.WorkspaceFolder): vscode.Task[] {
-    return [
-        { command: 'build', group: vscode.TaskGroup.Build },
-        { command: 'check', group: vscode.TaskGroup.Build },
-        { command: 'test', group: vscode.TaskGroup.Test },
-        { command: 'clean', group: vscode.TaskGroup.Clean },
-        { command: 'run', group: undefined },
-    ]
-        .map(({ command, group }) => {
-            const vscodeTask = new vscode.Task(
-                // The contents of this object end up in the tasks.json entries.
-                {
-                    type: TASK_TYPE,
-                    command,
-                },
-                // The scope of the task - workspace or specific folder (global
-                // is not supported).
-                target,
-                // The task name, and task source. These are shown in the UI as
-                // `${source}: ${name}`, e.g. `rust: cargo build`.
-                `cargo ${command}`,
+        const definition = task.definition as CargoTaskDefinition;
+
+        if (definition.type === 'cargo' && definition.command) {
+            const args = [definition.command].concat(definition.args ?? []);
+
+            return new vscode.Task(
+                definition,
+                task.name,
                 'rust',
-                // What to do when this command is executed.
-                new vscode.ShellExecution('cargo', [command]),
-                // Problem matchers.
-                ['$rustc'],
+                new vscode.ShellExecution('cargo', args, definition),
             );
-            vscodeTask.group = group;
-            return vscodeTask;
-        });
+        }
+
+        return undefined;
+    }
 }
+
+export function activateTaskProvider(target: vscode.WorkspaceFolder): vscode.Disposable {
+    const provider = new CargoTaskProvider(target);
+    return vscode.tasks.registerTaskProvider(TASK_TYPE, provider);
+}
\ No newline at end of file