improve completions in closures and switch statements

pkg/analysis_server/lib/src/services/completion/dart/optype.dart

Index: pkg/analysis_server/lib/src/services/completion/dart/optype.dart
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/optype.dart b/pkg/analysis_server/lib/src/services/completion/dart/optype.dart
index ea97679577cae9f42325d362da95c296d5143088..995ec2756827c7dd8c11bf8d13dc315097fb652a 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/optype.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/optype.dart
@@ -772,6 +772,10 @@ class _OpTypeAstVisitor extends GeneralizingAstVisitor {
     if (identical(entity, node.expression)) {
       optype.includeReturnValueSuggestions = true;
       optype.includeTypeNameSuggestions = true;
+    } else if (node.statements.contains(entity)) {
+      optype.includeReturnValueSuggestions = true;
+      optype.includeTypeNameSuggestions = true;
+      optype.includeVoidReturnSuggestions = true;
     }
   }
 
@@ -877,14 +881,6 @@ class _OpTypeAstVisitor extends GeneralizingAstVisitor {
     }
   }
 
-  bool _isEntityPrevToken(TokenType expectedType) {
-    Object entity = this.entity;
-    if (entity is SimpleIdentifier && entity.token.isSynthetic) {
-      return entity.token.previous.type == expectedType;
-    }
-    return false;
-  }
-
   bool _isEntityPrevTokenSynthetic() {
     Object entity = this.entity;
     if (entity is AstNode && entity.beginToken.previous?.isSynthetic ?? false) {