[analysis_server] Fix duplicate reporting of some LSP type parsing errors

Parse errors for spec types were being reported twice - once by the containing object (in canParse()), and once by the nested canParse() call for the nested type.

This skips reporting the error for nested calls to a canParse() method, which will always report the error itself.

Change-Id: I03e4a9638fd6a3fc77eac918f6fd16def93327d6
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/404105
Reviewed-by: Samuel Rawlins <srawlins@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>

pkg/analysis_server/test/tool/lsp_spec/json_test.dart

@@ -288,7 +288,7 @@ void main() {
       expect(reporter.errors.first, equals('params.kind must not be null'));
     });
 
-    test('canParse records fields of the wrong type', () {
+    test('canParse records fields of the wrong type (non-spec types)', () {
       var reporter = LspJsonReporter('params');
       expect(RenameFileOptions.canParse({'overwrite': 1}, reporter), isFalse);
       expect(reporter.errors, hasLength(1));
@@ -298,6 +298,20 @@ void main() {
       );
     });
 
+    test('canParse records fields of the wrong type (spec types)', () {
+      var reporter = LspJsonReporter('params');
+      expect(
+        ClientCapabilities.canParse({'textDocument': 1}, reporter),
+        isFalse,
+      );
+      expect(
+        reporter.errors.single,
+        equals(
+          'params.textDocument must be of type TextDocumentClientCapabilities',
+        ),
+      );
+    });
+
     test('canParse records nested undefined fields', () {
       var reporter = LspJsonReporter('params');
       expect(

pkg/analysis_server/tool/lsp_spec/codegen_dart.dart

@@ -514,8 +514,15 @@ void _writeCanParseType(
 
   buffer
     ..write(') {')
-    ..indent()
-    ..writeIndentedln('reporter.reportError($quote$failureMessage$quote);')
+    ..indent();
+  if (!_isSpecType(type)) {
+    // Only report an error for non-spec types, as spec types will have reported
+    // their own error in the nested canParse() call.
+    buffer.writeIndentedln(
+      'reporter.reportError($quote$failureMessage$quote);',
+    );
+  }
+  buffer
     ..writeIndentedln('return false;')
     ..outdent()
     ..writeIndentedln('}')

third_party/pkg/language_server_protocol/lib/protocol_custom_generated.dart

@@ -52,7 +52,6 @@ bool _canParseArgumentEdit(
     }
     if ((!nullCheck || value != null) &&
         !ArgumentEdit.canParse(value, reporter)) {
-      reporter.reportError('must be of type ArgumentEdit');
       return false;
     }
   } finally {
@@ -102,7 +101,6 @@ bool _canParseElement(
       return false;
     }
     if ((!nullCheck || value != null) && !Element.canParse(value, reporter)) {
-      reporter.reportError('must be of type Element');
       return false;
     }
   } finally {
@@ -128,7 +126,6 @@ bool _canParseErrorCodes(
     }
     if ((!nullCheck || value != null) &&
         !ErrorCodes.canParse(value, reporter)) {
-      reporter.reportError('must be of type ErrorCodes');
       return false;
     }
   } finally {
@@ -154,7 +151,6 @@ bool _canParseFlutterOutline(
     }
     if ((!nullCheck || value != null) &&
         !FlutterOutline.canParse(value, reporter)) {
-      reporter.reportError('must be of type FlutterOutline');
       return false;
     }
   } finally {
@@ -180,7 +176,6 @@ bool _canParseInsertTextFormat(
     }
     if ((!nullCheck || value != null) &&
         !InsertTextFormat.canParse(value, reporter)) {
-      reporter.reportError('must be of type InsertTextFormat');
       return false;
     }
   } finally {
@@ -501,7 +496,6 @@ bool _canParseMethod(
       return false;
     }
     if ((!nullCheck || value != null) && !Method.canParse(value, reporter)) {
-      reporter.reportError('must be of type Method');
       return false;
     }
   } finally {
@@ -526,7 +520,6 @@ bool _canParseOutline(
       return false;
     }
     if ((!nullCheck || value != null) && !Outline.canParse(value, reporter)) {
-      reporter.reportError('must be of type Outline');
       return false;
     }
   } finally {
@@ -551,7 +544,6 @@ bool _canParsePosition(
       return false;
     }
     if ((!nullCheck || value != null) && !Position.canParse(value, reporter)) {
-      reporter.reportError('must be of type Position');
       return false;
     }
   } finally {
@@ -576,7 +568,6 @@ bool _canParseRange(
       return false;
     }
     if ((!nullCheck || value != null) && !Range.canParse(value, reporter)) {
-      reporter.reportError('must be of type Range');
       return false;
     }
   } finally {
@@ -602,7 +593,6 @@ bool _canParseResponseError(
     }
     if ((!nullCheck || value != null) &&
         !ResponseError.canParse(value, reporter)) {
-      reporter.reportError('must be of type ResponseError');
       return false;
     }
   } finally {
@@ -653,7 +643,6 @@ bool _canParseTextDocumentIdentifier(
     }
     if ((!nullCheck || value != null) &&
         !TextDocumentIdentifier.canParse(value, reporter)) {
-      reporter.reportError('must be of type TextDocumentIdentifier');
       return false;
     }
   } finally {
@@ -679,7 +668,6 @@ bool _canParseTypeHierarchyAnchor(
     }
     if ((!nullCheck || value != null) &&
         !TypeHierarchyAnchor.canParse(value, reporter)) {
-      reporter.reportError('must be of type TypeHierarchyAnchor');
       return false;
     }
   } finally {