diff --git a/NOTICE b/NOTICE
index f9e5e9e9a2..672aca7358 100644
--- a/NOTICE
+++ b/NOTICE
@@ -15,6 +15,8 @@ under the licensing terms detailed in LICENSE:
 * Aaron Turner <aaron@aaronthedev.com>
 * Willem Wyndham <willem@cs.umd.edu>
 * Bowen Wang <bowen@nearprotocol.com>
+* Daniel Reed <daniel@reedcode.co.uk>
+* Karzan Botani <karzan@botani.nu>
 
 Portions of this software are derived from third-party works licensed under
 the following terms:
diff --git a/src/compiler.ts b/src/compiler.ts
index 7c49599078..7e9799dc61 100644
--- a/src/compiler.ts
+++ b/src/compiler.ts
@@ -1651,6 +1651,7 @@ export class Compiler extends DiagnosticEmitter {
         break;
       }
       case NodeKind.FIELDDECLARATION: {
+        if (!this.program.elementsByDeclaration.has(<FieldDeclaration>statement)) { break; }
         let element = this.program.getElementByDeclaration(<FieldDeclaration>statement);
         if (element.kind == ElementKind.GLOBAL) { // static
           if (!element.hasDecorator(DecoratorFlags.LAZY)) this.compileGlobal(<Global>element);
diff --git a/src/diagnosticMessages.generated.ts b/src/diagnosticMessages.generated.ts
index 5e6f076bbe..9c2e8b6787 100644
--- a/src/diagnosticMessages.generated.ts
+++ b/src/diagnosticMessages.generated.ts
@@ -36,6 +36,8 @@ export enum DiagnosticCode {
   _0_must_be_a_power_of_two = 223,
   Expression_is_unsafe = 224,
   Expression_is_never_null = 225,
+  Duplicate_instance_member_0 = 231,
+  Duplicate_static_member_0 = 232,
   Unterminated_string_literal = 1002,
   Identifier_expected = 1003,
   _0_expected = 1005,
@@ -176,6 +178,8 @@ export function diagnosticCodeToString(code: DiagnosticCode): string {
     case 223: return "'{0}' must be a power of two.";
     case 224: return "Expression is unsafe.";
     case 225: return "Expression is never 'null'.";
+    case 231: return "Duplicate instance member '{0}'.";
+    case 232: return "Duplicate static member '{0}'.";
     case 1002: return "Unterminated string literal.";
     case 1003: return "Identifier expected.";
     case 1005: return "'{0}' expected.";
diff --git a/src/diagnosticMessages.json b/src/diagnosticMessages.json
index 17c832cee4..e63d6c8361 100644
--- a/src/diagnosticMessages.json
+++ b/src/diagnosticMessages.json
@@ -28,6 +28,8 @@
   "'{0}' must be a power of two.": 223,
   "Expression is unsafe.": 224,
   "Expression is never 'null'.": 225,
+  "Duplicate instance member '{0}'.": 231,
+  "Duplicate static member '{0}'.": 232,
 
   "Unterminated string literal.": 1002,
   "Identifier expected.": 1003,
diff --git a/src/program.ts b/src/program.ts
index d71a1dc445..e6d24b7bb1 100644
--- a/src/program.ts
+++ b/src/program.ts
@@ -2038,10 +2038,17 @@ export abstract class Element {
         if (merged) {
           element = merged; // use merged element
         } else {
-          this.program.error(
-            DiagnosticCode.Duplicate_identifier_0,
-            element.identifierNode.range, element.identifierNode.text
-          );
+          if (element.is(CommonFlags.STATIC)) {
+            this.program.error(
+              DiagnosticCode.Duplicate_static_member_0,
+              element.identifierNode.range, element.identifierNode.text
+            );
+          } else {
+            this.program.error(
+              DiagnosticCode.Duplicate_identifier_0,
+              element.identifierNode.range, element.identifierNode.text
+            );
+          }
           return false;
         }
       }
@@ -3040,7 +3047,7 @@ export class ClassPrototype extends DeclaredElement {
       let merged = tryMerge(instanceMembers.get(name)!, element);
       if (!merged) {
         this.program.error(
-          DiagnosticCode.Duplicate_identifier_0,
+          DiagnosticCode.Duplicate_instance_member_0,
           element.identifierNode.range, element.identifierNode.text
         );
         return false;
diff --git a/tests/compiler/class-duplicate.json b/tests/compiler/class-duplicate.json
new file mode 100644
index 0000000000..1fd040b63f
--- /dev/null
+++ b/tests/compiler/class-duplicate.json
@@ -0,0 +1,10 @@
+{
+  "asc_flags": [
+    "--runtime none"
+  ],
+  "stderr": [
+    "AS231: Duplicate instance member 'field'.",
+    "AS232: Duplicate static member 'static_field'.",
+    "EOF"
+  ]
+}
\ No newline at end of file
diff --git a/tests/compiler/class-duplicate.ts b/tests/compiler/class-duplicate.ts
new file mode 100644
index 0000000000..1b2e97fb52
--- /dev/null
+++ b/tests/compiler/class-duplicate.ts
@@ -0,0 +1,13 @@
+// ERROR("SOF");
+
+class FailureTest {
+  field: i64;
+  field: u32;
+
+  static static_field: string;
+  static static_field: i32;
+}
+
+const fail = new FailureTest();
+
+ERROR("EOF");
\ No newline at end of file