implemented @deprecated diagnostics reporting

snapshots/input/diagnostics/index.ts

@@ -0,0 +1,18 @@
+/** @deprecated This class is deprecated */
+class Foo {}
+
+/** @deprecated This function is deprecated */
+function bar() {}
+
+/**
+ * @deprecated This is a function that has
+ * multiple lines and is also deprecated. Make
+ * sure to reference {@link bar} for some reason
+ */
+function car() {}
+
+function main() {
+  new Foo()
+  bar()
+  car()
+}

snapshots/input/diagnostics/package.json

@@ -0,0 +1,4 @@
+{
+  "name": "diagnostics",
+  "version": "0.0.1"
+}

snapshots/input/diagnostics/tsconfig.json

@@ -0,0 +1 @@
+{}

snapshots/output/diagnostics/index.ts

@@ -0,0 +1,36 @@
+// < definition diagnostics 0.0.1 `index.ts`/
+
+/** @deprecated This class is deprecated */
+class Foo {}
+//    ^^^ definition diagnostics 0.0.1 `index.ts`/Foo#
+
+/** @deprecated This function is deprecated */
+function bar() {}
+//       ^^^ definition diagnostics 0.0.1 `index.ts`/bar().
+
+/**
+ * @deprecated This is a function that has
+ * multiple lines and is also deprecated. Make
+ * sure to reference {@link bar} for some reason
+ */
+function car() {}
+//       ^^^ definition diagnostics 0.0.1 `index.ts`/car().
+
+function main() {
+//       ^^^^ definition diagnostics 0.0.1 `index.ts`/main().
+  new Foo()
+//    ^^^ reference diagnostics 0.0.1 `index.ts`/Foo#
+//    diagnostic Information:
+//    > This class is deprecated
+  bar()
+//^^^ reference diagnostics 0.0.1 `index.ts`/bar().
+//diagnostic Information:
+//> This function is deprecated
+  car()
+//^^^ reference diagnostics 0.0.1 `index.ts`/car().
+//diagnostic Information:
+//> This is a function that has
+//> multiple lines and is also deprecated. Make
+//> sure to reference {@link bar } for some reason
+}
+

src/FileIndexer.ts

@@ -242,6 +242,12 @@ export class FileIndexer {
           range,
           symbol: scipSymbol.value,
           symbol_roles: role,
+
+          // Diagnostics should only be added for references to the symbol, not
+          // the definition
+          diagnostics: !isDefinitionNode
+            ? this.diagnosticsForSymbol(sym)
+            : undefined,
         })
       )
       if (isDefinitionNode) {
@@ -718,6 +724,29 @@ export class FileIndexer {
     }
     loop(node)
   }
+
+  // Returns the scip diagnostics for a given typescript symbol
+  private diagnosticsForSymbol(
+    sym: ts.Symbol
+  ): scip.scip.Diagnostic[] | undefined {
+    const jsDocTags = sym.getJsDocTags()
+
+    const deprecatedTag = jsDocTags.find(tag => tag.name === 'deprecated')
+    if (deprecatedTag) {
+      return [
+        new scip.scip.Diagnostic({
+          severity: scip.scip.Severity.Information,
+          code: 'DEPRECATED',
+          // jsDocInfo.text is a tokenized representation of the tag text.
+          // Concatenate the elements to get the full message
+          message: deprecatedTag.text?.map(part => part.text).join(''),
+          tags: [scip.scip.DiagnosticTag.Deprecated],
+        }),
+      ]
+    }
+
+    return undefined
+  }
 }
 
 function isAnonymousContainerOfSymbols(node: ts.Node): boolean {

src/SnapshotTesting.ts

@@ -295,6 +295,19 @@ export function formatSnapshot(
       out.push(symbol.replace('\n', '|'))
 
       pushDoc(range, occurrence.symbol, isDefinition, isStartOfLine)
+
+      if (occurrence.diagnostics && occurrence.diagnostics.length > 0) {
+        for (let diagnostic of occurrence.diagnostics) {
+          let indent = ' '.repeat(range.start.character - 2)
+          out.push(commentSyntax + indent)
+          out.push(`diagnostic ${scip.Severity[diagnostic.severity]}:\n`)
+          if (diagnostic.message) {
+            for (let messageLine of diagnostic.message.split('\n')) {
+              out.push(`${commentSyntax + indent}> ${messageLine}\n`)
+            }
+          }
+        }
+      }
     }
 
     // Check if any enclosing ranges end on this line