From 21355982fd2c0c72ee507faed0d4b5a2f848245c Mon Sep 17 00:00:00 2001
From: Arthur Ozga <aozgaa-ms@outlook.com>
Date: Mon, 13 Feb 2017 16:58:14 -0800
Subject: [PATCH] Offer missing abstract codefix once

* per class that is missing potentially many abstract members.
---
 src/harness/fourslash.ts                        | 17 +++++++++++++++++
 src/services/services.ts                        |  8 +++++++-
 .../codeFixClassExtendAbstractProperty.ts       |  6 +++++-
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/src/harness/fourslash.ts b/src/harness/fourslash.ts
index fc85fb7276c..62770a96e7a 100644
--- a/src/harness/fourslash.ts
+++ b/src/harness/fourslash.ts
@@ -2153,12 +2153,29 @@ namespace FourSlash {
             const diagnostics: ts.Diagnostic[] = this.getDiagnostics(fileName);
 
             let actions: ts.CodeAction[] = undefined;
+
+            const checkedDiagnostics = ts.createMap<boolean>();
+
             for (const diagnostic of diagnostics) {
 
                 if (errorCode && errorCode !== diagnostic.code) {
                     continue;
                 }
 
+                const summary = JSON.stringify({
+                    start: diagnostic.start,
+                    length: diagnostic.length,
+                    code: diagnostic.code
+                });
+
+                if (checkedDiagnostics.has(summary)) {
+                    // Don't want to ask for code fixes in an identical position for the same error code twice.
+                    continue;
+                }
+                else {
+                    checkedDiagnostics.set(summary, true);
+                }
+
                 const newActions = this.languageService.getCodeFixesAtPosition(fileName, diagnostic.start, diagnostic.length, [diagnostic.code]);
                 if (newActions && newActions.length) {
                     actions = actions ? actions.concat(newActions) : newActions;
diff --git a/src/services/services.ts b/src/services/services.ts
index b83995e31ed..35588a1902a 100644
--- a/src/services/services.ts
+++ b/src/services/services.ts
@@ -1688,7 +1688,13 @@ namespace ts {
 
             let allFixes: CodeAction[] = [];
 
-            forEach(errorCodes, error => {
+            // De-duplicate error codes.
+            const errorCodeSet: number[] = [];
+            for (const code of errorCodes) {
+                errorCodeSet[code] = code;
+            }
+
+            forEach(errorCodeSet, error => {
                 cancellationToken.throwIfCancellationRequested();
 
                 const context = {
diff --git a/tests/cases/fourslash/codeFixClassExtendAbstractProperty.ts b/tests/cases/fourslash/codeFixClassExtendAbstractProperty.ts
index 46de88f7511..3160a3b9a08 100644
--- a/tests/cases/fourslash/codeFixClassExtendAbstractProperty.ts
+++ b/tests/cases/fourslash/codeFixClassExtendAbstractProperty.ts
@@ -2,11 +2,15 @@
 
 //// abstract class A {
 ////    abstract x: number;
+////    abstract foo(): number;
 //// }
 ////
 //// class C extends A {[|
 //// |]}
 
 verify.rangeAfterCodeFix(`
-x: number;
+    x: number;
+    foo(): number {
+        throw new Error('Method not implemented.');
+    }
 `);