Update compiler/src/dotty/tools/dotc/core/NameOps.scala

Co-authored-by: Jamie Thompson <bishbashboshjt@gmail.com>

Author: tudorv91

.jvmopts

@@ -1,4 +1,4 @@
--Xss1m
--Xms512m
--Xmx1200m
+-Xss10m
+-Xms1024m
+-Xmx4096m
 -XX:MaxInlineLevel=35

compiler/src/dotty/tools/dotc/core/NameOps.scala

@@ -134,7 +134,10 @@ object NameOps {
     }
 
     /** Does the name match `extension`? */
-    def isExtension: Boolean = name.toString == "extension"
+    def isExtension: Boolean = name match
+      case name: SimpleName =>
+        name.length == "extension".length && name.startsWith("extension")
+      case _ => false
 
     /** Does this name start with `extension_`? */
     def isExtensionName: Boolean = name match

tests/neg/illegal-extension.check

@@ -9,7 +9,7 @@
 -- Error: tests/neg/illegal-extension.scala:5:14 -----------------------------------------------------------------------
 5 |  private var extension = Nil // error: not allowed because it matches `extension`
   |              ^^^^^^^^^
-  |              illegal variable name: `extension`
+  |              illegal setter name: `extension_=`
 -- Error: tests/neg/illegal-extension.scala:8:23 -----------------------------------------------------------------------
 8 |extension (x: Any) def extension_foo: String = "foo" // error: illegal name: extension_foo may not start with `extension_`
   |                       ^^^^^^^^^^^^^