Merge #1454

1454: Fix `cargo watch` code action filtering r=etaoins a=etaoins

There are two issues with the implementation of `provideCodeActions` introduced in #1439:

1. We're returning the code action based on the file its diagnostic is in; not the file the suggested fix is in. I'm not sure how often fixes are suggested cross-file but it's something we should handle.

2. We're not filtering code actions based on the passed range. The means if there is any suggestion in a file we'll show an action for every line of the file. I naively thought that VS Code would filter for us but that was wrong.

Unfortunately the VS Code `CodeAction` object is very complex - it can handle edits across multiple files, run commands, etc. This makes it complex to check them for equality or see if any of their edits intersects with a specified range.

To make it easier to work with suggestions this introduces a `SuggestedFix` model object and a `SuggestFixCollection` code action provider. This is a layer between the raw Rust JSON and VS Code's `CodeAction`s. I was reluctant to introduce another layer of abstraction here but my attempt to work directly with VS Code's model objects was worse.

Co-authored-by: Ryan Cumming <[email protected]>

1 files changed, 173 insertions, 0 deletions

diff --git a/editors/code/src/test/utils/diagnotics/rust.test.ts b/editors/code/src/test/utils/diagnotics/rust.test.ts
new file mode 100644
index 000000000..b555a4819
--- /dev/null
+++ b/editors/code/src/test/utils/diagnotics/rust.test.ts
@@ -0,0 +1,173 @@
+import * as assert from 'assert';
+import * as fs from 'fs';
+import * as vscode from 'vscode';
+
+import {
+    MappedRustDiagnostic,
+    mapRustDiagnosticToVsCode,
+    RustDiagnostic,
+    SuggestionApplicability
+} from '../../../utils/diagnostics/rust';
+
+function loadDiagnosticFixture(name: string): RustDiagnostic {
+    const jsonText = fs
+        .readFileSync(
+            // We're actually in our JavaScript output directory, climb out
+            `${__dirname}/../../../../src/test/fixtures/rust-diagnostics/${name}.json`
+        )
+        .toString();
+
+    return JSON.parse(jsonText);
+}
+
+function mapFixtureToVsCode(name: string): MappedRustDiagnostic {
+    const rd = loadDiagnosticFixture(name);
+    const mapResult = mapRustDiagnosticToVsCode(rd);
+
+    if (!mapResult) {
+        return assert.fail('Mapping unexpectedly failed');
+    }
+    return mapResult;
+}
+
+describe('mapRustDiagnosticToVsCode', () => {
+    it('should map an incompatible type for trait error', () => {
+        const { diagnostic, suggestedFixes } = mapFixtureToVsCode(
+            'error/E0053'
+        );
+
+        assert.strictEqual(
+            diagnostic.severity,
+            vscode.DiagnosticSeverity.Error
+        );
+        assert.strictEqual(diagnostic.source, 'rustc');
+        assert.strictEqual(
+            diagnostic.message,
+            [
+                `method \`next\` has an incompatible type for trait`,
+                `expected type \`fn(&mut ty::list_iter::ListIterator<'list, M>) -> std::option::Option<&ty::Ref<M>>\``,
+                `   found type \`fn(&ty::list_iter::ListIterator<'list, M>) -> std::option::Option<&'list ty::Ref<M>>\``
+            ].join('\n')
+        );
+        assert.strictEqual(diagnostic.code, 'E0053');
+        assert.strictEqual(diagnostic.tags, undefined);
+
+        // No related information
+        assert.deepStrictEqual(diagnostic.relatedInformation, []);
+
+        // There are no suggested fixes
+        assert.strictEqual(suggestedFixes.length, 0);
+    });
+
+    it('should map an unused variable warning', () => {
+        const { diagnostic, suggestedFixes } = mapFixtureToVsCode(
+            'warning/unused_variables'
+        );
+
+        assert.strictEqual(
+            diagnostic.severity,
+            vscode.DiagnosticSeverity.Warning
+        );
+        assert.strictEqual(
+            diagnostic.message,
+            [
+                'unused variable: `foo`',
+                '#[warn(unused_variables)] on by default'
+            ].join('\n')
+        );
+        assert.strictEqual(diagnostic.code, 'unused_variables');
+        assert.strictEqual(diagnostic.source, 'rustc');
+        assert.deepStrictEqual(diagnostic.tags, [
+            vscode.DiagnosticTag.Unnecessary
+        ]);
+
+        // No related information
+        assert.deepStrictEqual(diagnostic.relatedInformation, []);
+
+        // One suggested fix available to prefix the variable
+        assert.strictEqual(suggestedFixes.length, 1);
+        const [suggestedFix] = suggestedFixes;
+        assert.strictEqual(
+            suggestedFix.title,
+            'consider prefixing with an underscore: `_foo`'
+        );
+        assert.strictEqual(
+            suggestedFix.applicability,
+            SuggestionApplicability.MachineApplicable
+        );
+    });
+
+    it('should map a wrong number of parameters error', () => {
+        const { diagnostic, suggestedFixes } = mapFixtureToVsCode(
+            'error/E0061'
+        );
+
+        assert.strictEqual(
+            diagnostic.severity,
+            vscode.DiagnosticSeverity.Error
+        );
+        assert.strictEqual(
+            diagnostic.message,
+            'this function takes 2 parameters but 3 parameters were supplied'
+        );
+        assert.strictEqual(diagnostic.code, 'E0061');
+        assert.strictEqual(diagnostic.source, 'rustc');
+        assert.strictEqual(diagnostic.tags, undefined);
+
+        // One related information for the original definition
+        const relatedInformation = diagnostic.relatedInformation;
+        if (!relatedInformation) {
+            return assert.fail('Related information unexpectedly undefined');
+        }
+        assert.strictEqual(relatedInformation.length, 1);
+        const [related] = relatedInformation;
+        assert.strictEqual(related.message, 'defined here');
+
+        // There are no suggested fixes
+        assert.strictEqual(suggestedFixes.length, 0);
+    });
+
+    it('should map a Clippy copy pass by ref warning', () => {
+        const { diagnostic, suggestedFixes } = mapFixtureToVsCode(
+            'clippy/trivially_copy_pass_by_ref'
+        );
+
+        assert.strictEqual(
+            diagnostic.severity,
+            vscode.DiagnosticSeverity.Warning
+        );
+        assert.strictEqual(diagnostic.source, 'clippy');
+        assert.strictEqual(
+            diagnostic.message,
+            [
+                'this argument is passed by reference, but would be more efficient if passed by value',
+                '#[warn(clippy::trivially_copy_pass_by_ref)] implied by #[warn(clippy::all)]',
+                'for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#trivially_copy_pass_by_ref'
+            ].join('\n')
+        );
+        assert.strictEqual(diagnostic.code, 'trivially_copy_pass_by_ref');
+        assert.strictEqual(diagnostic.tags, undefined);
+
+        // One related information for the lint definition
+        const relatedInformation = diagnostic.relatedInformation;
+        if (!relatedInformation) {
+            return assert.fail('Related information unexpectedly undefined');
+        }
+        assert.strictEqual(relatedInformation.length, 1);
+        const [related] = relatedInformation;
+        assert.strictEqual(related.message, 'lint level defined here');
+
+        // One suggested fix to pass by value
+        assert.strictEqual(suggestedFixes.length, 1);
+        const [suggestedFix] = suggestedFixes;
+        assert.strictEqual(
+            suggestedFix.title,
+            'consider passing by value instead: `self`'
+        );
+        // Clippy does not mark this with any applicability
+        assert.strictEqual(
+            suggestedFix.applicability,
+            SuggestionApplicability.Unspecified
+        );
+    });
+});