diff --git a/scripts/processDiagnosticMessages.ts b/scripts/processDiagnosticMessages.ts
index dd66564b134..5b45fdeaae8 100644
--- a/scripts/processDiagnosticMessages.ts
+++ b/scripts/processDiagnosticMessages.ts
@@ -4,6 +4,7 @@
 interface DiagnosticDetails {
     category: string;
     code: number;
+    reportsUnnecessary?: {};
     isEarly?: boolean;
 }
 
@@ -59,14 +60,15 @@ function buildInfoFileOutput(messageTable: InputDiagnosticMessageTable, inputFil
         "/// <reference path=\"types.ts\" />\r\n" +
         "/* @internal */\r\n" +
         "namespace ts {\r\n" +
-        "    function diag(code: number, category: DiagnosticCategory, key: string, message: string): DiagnosticMessage {\r\n" +
-        "        return { code, category, key, message };\r\n" +
+        "    function diag(code: number, category: DiagnosticCategory, key: string, message: string, reportsUnnecessary?: {}): DiagnosticMessage {\r\n" +
+        "        return { code, category, key, message, reportsUnnecessary };\r\n" +
         "    }\r\n" +
         "    // tslint:disable-next-line variable-name\r\n" +
         "    export const Diagnostics = {\r\n";
-    messageTable.forEach(({ code, category }, name) => {
+    messageTable.forEach(({ code, category, reportsUnnecessary }, name) => {
         const propName = convertPropertyName(name);
-        result += `        ${propName}: diag(${code}, DiagnosticCategory.${category}, "${createKey(propName, code)}", ${JSON.stringify(name)}),\r\n`;
+        const argReportsUnnecessary = reportsUnnecessary ? `, /*reportsUnnecessary*/ ${reportsUnnecessary}` : "";
+        result += `        ${propName}: diag(${code}, DiagnosticCategory.${category}, "${createKey(propName, code)}", ${JSON.stringify(name)}${argReportsUnnecessary}),\r\n`;
     });
 
     result += "    };\r\n}";
diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index 2d3b2a2a0ce..cbfcf127200 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -1606,7 +1606,7 @@ namespace ts {
             messageText: text,
             category: message.category,
             code: message.code,
-            reportsUnnecessary: message.unused,
+            reportsUnnecessary: message.reportsUnnecessary,
         };
     }
 
@@ -1637,7 +1637,7 @@ namespace ts {
             messageText: text,
             category: message.category,
             code: message.code,
-            reportsUnnecessary: message.unused,
+            reportsUnnecessary: message.reportsUnnecessary,
         };
     }
 
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 69a90fbabf5..2b56e551f1b 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -3286,7 +3286,7 @@
     "'{0}' is declared but its value is never read.": {
         "category": "Error",
         "code": 6133,
-        "unused": true
+        "reportsUnnecessary": true
     },
     "Report errors on unused locals.": {
         "category": "Message",
@@ -3307,7 +3307,7 @@
     "Property '{0}' is declared but its value is never read.": {
         "category": "Error",
         "code": 6138,
-        "unused": true
+        "reportsUnnecessary": true
     },
     "Import emit helpers from 'tslib'.": {
         "category": "Message",
@@ -3520,7 +3520,7 @@
     "All imports in import declaration are unused.": {
         "category": "Error",
         "code": 6192,
-        "unused": true
+        "reportsUnnecessary": true
     },
     "Found 1 error.": {
         "category": "Message",
@@ -3609,7 +3609,7 @@
     "Unused label.": {
         "category": "Error",
         "code": 7028,
-        "unused": true
+        "reportsUnnecessary": true
     },
     "Fallthrough case in switch.": {
         "category": "Error",
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index ac32d91c61a..f0aba4a34d7 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -4076,7 +4076,7 @@ namespace ts {
         category: DiagnosticCategory;
         code: number;
         message: string;
-        unused?: {};
+        reportsUnnecessary?: {};
     }
 
     /**
diff --git a/src/harness/unittests/tsserverProjectSystem.ts b/src/harness/unittests/tsserverProjectSystem.ts
index 8170c663b1f..ab0b1cf734d 100644
--- a/src/harness/unittests/tsserverProjectSystem.ts
+++ b/src/harness/unittests/tsserverProjectSystem.ts
@@ -4131,10 +4131,10 @@ namespace ts.projectSystem {
             checkErrorMessage(session, "semanticDiag", { file: file1.path, diagnostics: [] });
         });
 
-        it("info diagnostics", () => {
+        it("suggestion diagnostics", () => {
             const file: FileOrFolder = {
                 path: "/a.js",
-                content: 'require("b")',
+                content: "function f(p) {}",
             };
 
             const host = createServerHost([file]);
@@ -4177,7 +4177,7 @@ namespace ts.projectSystem {
             checkErrorMessage(session, "suggestionDiag", {
                 file: file.path,
                 diagnostics: [
-                    createDiagnostic({ line: 1, offset: 1 }, { line: 1, offset: 13 }, Diagnostics.File_is_a_CommonJS_module_it_may_be_converted_to_an_ES6_module)
+                    createDiagnostic({ line: 1, offset: 12 }, { line: 1, offset: 13 }, Diagnostics._0_is_declared_but_its_value_is_never_read, ["p"], "suggestion", /*reportsUnnecssary*/ true)
                 ],
             });
             checkCompleteEvent(session, 2, expectedSequenceId);
@@ -4241,8 +4241,8 @@ namespace ts.projectSystem {
             session.clearMessages();
         });
 
-        function createDiagnostic(start: protocol.Location, end: protocol.Location, message: DiagnosticMessage, args: ReadonlyArray<string> = []): protocol.Diagnostic {
-            return { start, end, text: formatStringFromArgs(message.message, args), code: message.code, category: diagnosticCategoryName(message), source: undefined };
+        function createDiagnostic(start: protocol.Location, end: protocol.Location, message: DiagnosticMessage, args: ReadonlyArray<string> = [], category = diagnosticCategoryName(message), reportsUnnecessary?: {}): protocol.Diagnostic {
+            return { start, end, text: formatStringFromArgs(message.message, args), code: message.code, category, reportsUnnecessary, source: undefined };
         }
     });
 
diff --git a/src/server/protocol.ts b/src/server/protocol.ts
index 74b6865a3c3..52427413aed 100644
--- a/src/server/protocol.ts
+++ b/src/server/protocol.ts
@@ -2172,6 +2172,8 @@ namespace ts.server.protocol {
          */
         category: string;
 
+        reportsUnnecessary?: {};
+
         /**
          * The error code of the diagnostic message.
          */
diff --git a/src/server/session.ts b/src/server/session.ts
index 3979687d631..c6066723892 100644
--- a/src/server/session.ts
+++ b/src/server/session.ts
@@ -80,6 +80,7 @@ namespace ts.server {
             text: flattenDiagnosticMessageText(diag.messageText, "\n"),
             code: diag.code,
             category: diagnosticCategoryName(diag),
+            reportsUnnecessary: diag.reportsUnnecessary,
             source: diag.source
         };
     }
@@ -96,8 +97,8 @@ namespace ts.server {
         const text = flattenDiagnosticMessageText(diag.messageText, "\n");
         const { code, source } = diag;
         const category = diagnosticCategoryName(diag);
-        return includeFileName ? { start, end, text, code, category, source, fileName: diag.file && diag.file.fileName } :
-            { start, end, text, code, category, source };
+        return includeFileName ? { start, end, text, code, category, source, reportsUnnecessary: diag.reportsUnnecessary, fileName: diag.file && diag.file.fileName } :
+            { start, end, text, code, category, reportsUnnecessary: diag.reportsUnnecessary, source };
     }
 
     export interface PendingErrorCheck {
diff --git a/tests/baselines/reference/api/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
index f602e872c14..49b9c2b5eca 100644
--- a/tests/baselines/reference/api/tsserverlibrary.d.ts
+++ b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -2275,7 +2275,7 @@ declare namespace ts {
         category: DiagnosticCategory;
         code: number;
         message: string;
-        unused?: {};
+        reportsUnnecessary?: {};
     }
     /**
      * A linked list of formatted diagnostic messages to be used as part of a multiline message.
@@ -6758,6 +6758,7 @@ declare namespace ts.server.protocol {
          * The category of the diagnostic message, e.g. "error", "warning", or "suggestion".
          */
         category: string;
+        reportsUnnecessary?: {};
         /**
          * The error code of the diagnostic message.
          */
diff --git a/tests/baselines/reference/api/typescript.d.ts b/tests/baselines/reference/api/typescript.d.ts
index 94fd684daee..f8a63a21575 100644
--- a/tests/baselines/reference/api/typescript.d.ts
+++ b/tests/baselines/reference/api/typescript.d.ts
@@ -2275,7 +2275,7 @@ declare namespace ts {
         category: DiagnosticCategory;
         code: number;
         message: string;
-        unused?: {};
+        reportsUnnecessary?: {};
     }
     /**
      * A linked list of formatted diagnostic messages to be used as part of a multiline message.