From 8f726b7db65d3d9527cdb2fb682c195ad1446dbf Mon Sep 17 00:00:00 2001
From: Ryan Cumming <etaoins@gmail.com>
Date: Sun, 30 Jun 2019 10:49:07 +1000
Subject: Include primary span label in VS Code diagnostics

In most cases the primary label span repeats information found elsewhere
in the diagnostic. For example, with E0061:

```
{
  "message": "this function takes 2 parameters but 3 parameters were supplied",
  "spans": [{"label": "expected 2 parameters"}]
}
```

However, with some mismatched type errors (E0308) the expected type only
appears in the primary span's label, e.g.:

```
{
  "message": "mismatched types",
  "spans": [{"label": "expected usize, found u32"}]
}
```

I initially added the primary span label to the message unconditionally.
However, for most error types the child diagnostics repeat the primary
span label with more detail. `rustc` also renders the duplicate text but
because the span label and child diagnostics appear in visually distinct
places it's not as confusing.

This takes a heuristic approach where it will only add the primary span
label if there are no child message lines.
---
 .../code/src/test/utils/diagnotics/rust.test.ts    | 29 +++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

(limited to 'editors/code/src/test/utils/diagnotics')

diff --git a/editors/code/src/test/utils/diagnotics/rust.test.ts b/editors/code/src/test/utils/diagnotics/rust.test.ts
index b555a4819..7fb003fe2 100644
--- a/editors/code/src/test/utils/diagnotics/rust.test.ts
+++ b/editors/code/src/test/utils/diagnotics/rust.test.ts
@@ -108,7 +108,10 @@ describe('mapRustDiagnosticToVsCode', () => {
         );
         assert.strictEqual(
             diagnostic.message,
-            'this function takes 2 parameters but 3 parameters were supplied'
+            [
+                'this function takes 2 parameters but 3 parameters were supplied',
+                'expected 2 parameters'
+            ].join('\n')
         );
         assert.strictEqual(diagnostic.code, 'E0061');
         assert.strictEqual(diagnostic.source, 'rustc');
@@ -170,4 +173,28 @@ describe('mapRustDiagnosticToVsCode', () => {
             SuggestionApplicability.Unspecified
         );
     });
+
+    it('should map a mismatched type error', () => {
+        const { diagnostic, suggestedFixes } = mapFixtureToVsCode(
+            'error/E0308'
+        );
+
+        assert.strictEqual(
+            diagnostic.severity,
+            vscode.DiagnosticSeverity.Error
+        );
+        assert.strictEqual(
+            diagnostic.message,
+            ['mismatched types', 'expected usize, found u32'].join('\n')
+        );
+        assert.strictEqual(diagnostic.code, 'E0308');
+        assert.strictEqual(diagnostic.source, 'rustc');
+        assert.strictEqual(diagnostic.tags, undefined);
+
+        // No related information
+        assert.deepStrictEqual(diagnostic.relatedInformation, []);
+
+        // There are no suggested fixes
+        assert.strictEqual(suggestedFixes.length, 0);
+    });
 });
-- 
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