diff --git a/lib/tsc.js b/lib/tsc.js
index ad02a9dcaf3..f9cbdae0d69 100644
--- a/lib/tsc.js
+++ b/lib/tsc.js
@@ -24942,7 +24942,7 @@ var ts;
     function getDeclarationDiagnostics(host, resolver, targetSourceFile) {
         var declarationDiagnostics = ts.createDiagnosticCollection();
         ts.forEachExpectedEmitFile(host, getDeclarationDiagnosticsFromFile, targetSourceFile);
-        return declarationDiagnostics.getDiagnostics(targetSourceFile.fileName);
+        return declarationDiagnostics.getDiagnostics(targetSourceFile ? targetSourceFile.fileName : undefined);
         function getDeclarationDiagnosticsFromFile(_a, sources, isBundledEmit) {
             var declarationFilePath = _a.declarationFilePath;
             emitDeclarations(host, resolver, declarationDiagnostics, declarationFilePath, sources, isBundledEmit);
@@ -32972,7 +32972,13 @@ var ts;
             return getDiagnosticsHelper(sourceFile, getSemanticDiagnosticsForFile, cancellationToken);
         }
         function getDeclarationDiagnostics(sourceFile, cancellationToken) {
-            return getDiagnosticsHelper(sourceFile, getDeclarationDiagnosticsForFile, cancellationToken);
+            var options = program.getCompilerOptions();
+            if (!sourceFile || options.out || options.outFile) {
+                return getDeclarationDiagnosticsWorker(sourceFile, cancellationToken);
+            }
+            else {
+                return getDiagnosticsHelper(sourceFile, getDeclarationDiagnosticsForFile, cancellationToken);
+            }
         }
         function getSyntacticDiagnosticsForFile(sourceFile, cancellationToken) {
             return sourceFile.parseDiagnostics;
@@ -33153,15 +33159,16 @@ var ts;
                 }
             });
         }
-        function getDeclarationDiagnosticsForFile(sourceFile, cancellationToken) {
+        function getDeclarationDiagnosticsWorker(sourceFile, cancellationToken) {
             return runWithCancellationToken(function () {
-                if (!ts.isDeclarationFile(sourceFile)) {
-                    var resolver = getDiagnosticsProducingTypeChecker().getEmitResolver(sourceFile, cancellationToken);
-                    var writeFile_1 = function () { };
-                    return ts.getDeclarationDiagnostics(getEmitHost(writeFile_1), resolver, sourceFile);
-                }
+                var resolver = getDiagnosticsProducingTypeChecker().getEmitResolver(sourceFile, cancellationToken);
+                var writeFile = function () { };
+                return ts.getDeclarationDiagnostics(getEmitHost(writeFile), resolver, sourceFile);
             });
         }
+        function getDeclarationDiagnosticsForFile(sourceFile, cancellationToken) {
+            return ts.isDeclarationFile(sourceFile) ? [] : getDeclarationDiagnosticsWorker(sourceFile, cancellationToken);
+        }
         function getOptionsDiagnostics() {
             var allDiagnostics = [];
             ts.addRange(allDiagnostics, fileProcessingDiagnostics.getGlobalDiagnostics());
diff --git a/lib/tsserver.js b/lib/tsserver.js
index c668238b5ce..47436063545 100644
--- a/lib/tsserver.js
+++ b/lib/tsserver.js
@@ -25510,7 +25510,7 @@ var ts;
     function getDeclarationDiagnostics(host, resolver, targetSourceFile) {
         var declarationDiagnostics = ts.createDiagnosticCollection();
         ts.forEachExpectedEmitFile(host, getDeclarationDiagnosticsFromFile, targetSourceFile);
-        return declarationDiagnostics.getDiagnostics(targetSourceFile.fileName);
+        return declarationDiagnostics.getDiagnostics(targetSourceFile ? targetSourceFile.fileName : undefined);
         function getDeclarationDiagnosticsFromFile(_a, sources, isBundledEmit) {
             var declarationFilePath = _a.declarationFilePath;
             emitDeclarations(host, resolver, declarationDiagnostics, declarationFilePath, sources, isBundledEmit);
@@ -33540,7 +33540,13 @@ var ts;
             return getDiagnosticsHelper(sourceFile, getSemanticDiagnosticsForFile, cancellationToken);
         }
         function getDeclarationDiagnostics(sourceFile, cancellationToken) {
-            return getDiagnosticsHelper(sourceFile, getDeclarationDiagnosticsForFile, cancellationToken);
+            var options = program.getCompilerOptions();
+            if (!sourceFile || options.out || options.outFile) {
+                return getDeclarationDiagnosticsWorker(sourceFile, cancellationToken);
+            }
+            else {
+                return getDiagnosticsHelper(sourceFile, getDeclarationDiagnosticsForFile, cancellationToken);
+            }
         }
         function getSyntacticDiagnosticsForFile(sourceFile, cancellationToken) {
             return sourceFile.parseDiagnostics;
@@ -33721,15 +33727,16 @@ var ts;
                 }
             });
         }
-        function getDeclarationDiagnosticsForFile(sourceFile, cancellationToken) {
+        function getDeclarationDiagnosticsWorker(sourceFile, cancellationToken) {
             return runWithCancellationToken(function () {
-                if (!ts.isDeclarationFile(sourceFile)) {
-                    var resolver = getDiagnosticsProducingTypeChecker().getEmitResolver(sourceFile, cancellationToken);
-                    var writeFile_1 = function () { };
-                    return ts.getDeclarationDiagnostics(getEmitHost(writeFile_1), resolver, sourceFile);
-                }
+                var resolver = getDiagnosticsProducingTypeChecker().getEmitResolver(sourceFile, cancellationToken);
+                var writeFile = function () { };
+                return ts.getDeclarationDiagnostics(getEmitHost(writeFile), resolver, sourceFile);
             });
         }
+        function getDeclarationDiagnosticsForFile(sourceFile, cancellationToken) {
+            return ts.isDeclarationFile(sourceFile) ? [] : getDeclarationDiagnosticsWorker(sourceFile, cancellationToken);
+        }
         function getOptionsDiagnostics() {
             var allDiagnostics = [];
             ts.addRange(allDiagnostics, fileProcessingDiagnostics.getGlobalDiagnostics());
diff --git a/lib/typescript.js b/lib/typescript.js
index b388d96b078..bb880f52c1a 100644
--- a/lib/typescript.js
+++ b/lib/typescript.js
@@ -30548,7 +30548,7 @@ var ts;
     function getDeclarationDiagnostics(host, resolver, targetSourceFile) {
         var declarationDiagnostics = ts.createDiagnosticCollection();
         ts.forEachExpectedEmitFile(host, getDeclarationDiagnosticsFromFile, targetSourceFile);
-        return declarationDiagnostics.getDiagnostics(targetSourceFile.fileName);
+        return declarationDiagnostics.getDiagnostics(targetSourceFile ? targetSourceFile.fileName : undefined);
         function getDeclarationDiagnosticsFromFile(_a, sources, isBundledEmit) {
             var declarationFilePath = _a.declarationFilePath;
             emitDeclarations(host, resolver, declarationDiagnostics, declarationFilePath, sources, isBundledEmit);
@@ -39825,7 +39825,14 @@ var ts;
             return getDiagnosticsHelper(sourceFile, getSemanticDiagnosticsForFile, cancellationToken);
         }
         function getDeclarationDiagnostics(sourceFile, cancellationToken) {
-            return getDiagnosticsHelper(sourceFile, getDeclarationDiagnosticsForFile, cancellationToken);
+            var options = program.getCompilerOptions();
+            // collect diagnostics from the program only once if either no source file was specified or out/outFile is set (bundled emit)
+            if (!sourceFile || options.out || options.outFile) {
+                return getDeclarationDiagnosticsWorker(sourceFile, cancellationToken);
+            }
+            else {
+                return getDiagnosticsHelper(sourceFile, getDeclarationDiagnosticsForFile, cancellationToken);
+            }
         }
         function getSyntacticDiagnosticsForFile(sourceFile, cancellationToken) {
             return sourceFile.parseDiagnostics;
@@ -40019,16 +40026,17 @@ var ts;
                 }
             });
         }
-        function getDeclarationDiagnosticsForFile(sourceFile, cancellationToken) {
+        function getDeclarationDiagnosticsWorker(sourceFile, cancellationToken) {
             return runWithCancellationToken(function () {
-                if (!ts.isDeclarationFile(sourceFile)) {
-                    var resolver = getDiagnosticsProducingTypeChecker().getEmitResolver(sourceFile, cancellationToken);
-                    // Don't actually write any files since we're just getting diagnostics.
-                    var writeFile_1 = function () { };
-                    return ts.getDeclarationDiagnostics(getEmitHost(writeFile_1), resolver, sourceFile);
-                }
+                var resolver = getDiagnosticsProducingTypeChecker().getEmitResolver(sourceFile, cancellationToken);
+                // Don't actually write any files since we're just getting diagnostics.
+                var writeFile = function () { };
+                return ts.getDeclarationDiagnostics(getEmitHost(writeFile), resolver, sourceFile);
             });
         }
+        function getDeclarationDiagnosticsForFile(sourceFile, cancellationToken) {
+            return ts.isDeclarationFile(sourceFile) ? [] : getDeclarationDiagnosticsWorker(sourceFile, cancellationToken);
+        }
         function getOptionsDiagnostics() {
             var allDiagnostics = [];
             ts.addRange(allDiagnostics, fileProcessingDiagnostics.getGlobalDiagnostics());
diff --git a/lib/typescriptServices.js b/lib/typescriptServices.js
index b388d96b078..bb880f52c1a 100644
--- a/lib/typescriptServices.js
+++ b/lib/typescriptServices.js
@@ -30548,7 +30548,7 @@ var ts;
     function getDeclarationDiagnostics(host, resolver, targetSourceFile) {
         var declarationDiagnostics = ts.createDiagnosticCollection();
         ts.forEachExpectedEmitFile(host, getDeclarationDiagnosticsFromFile, targetSourceFile);
-        return declarationDiagnostics.getDiagnostics(targetSourceFile.fileName);
+        return declarationDiagnostics.getDiagnostics(targetSourceFile ? targetSourceFile.fileName : undefined);
         function getDeclarationDiagnosticsFromFile(_a, sources, isBundledEmit) {
             var declarationFilePath = _a.declarationFilePath;
             emitDeclarations(host, resolver, declarationDiagnostics, declarationFilePath, sources, isBundledEmit);
@@ -39825,7 +39825,14 @@ var ts;
             return getDiagnosticsHelper(sourceFile, getSemanticDiagnosticsForFile, cancellationToken);
         }
         function getDeclarationDiagnostics(sourceFile, cancellationToken) {
-            return getDiagnosticsHelper(sourceFile, getDeclarationDiagnosticsForFile, cancellationToken);
+            var options = program.getCompilerOptions();
+            // collect diagnostics from the program only once if either no source file was specified or out/outFile is set (bundled emit)
+            if (!sourceFile || options.out || options.outFile) {
+                return getDeclarationDiagnosticsWorker(sourceFile, cancellationToken);
+            }
+            else {
+                return getDiagnosticsHelper(sourceFile, getDeclarationDiagnosticsForFile, cancellationToken);
+            }
         }
         function getSyntacticDiagnosticsForFile(sourceFile, cancellationToken) {
             return sourceFile.parseDiagnostics;
@@ -40019,16 +40026,17 @@ var ts;
                 }
             });
         }
-        function getDeclarationDiagnosticsForFile(sourceFile, cancellationToken) {
+        function getDeclarationDiagnosticsWorker(sourceFile, cancellationToken) {
             return runWithCancellationToken(function () {
-                if (!ts.isDeclarationFile(sourceFile)) {
-                    var resolver = getDiagnosticsProducingTypeChecker().getEmitResolver(sourceFile, cancellationToken);
-                    // Don't actually write any files since we're just getting diagnostics.
-                    var writeFile_1 = function () { };
-                    return ts.getDeclarationDiagnostics(getEmitHost(writeFile_1), resolver, sourceFile);
-                }
+                var resolver = getDiagnosticsProducingTypeChecker().getEmitResolver(sourceFile, cancellationToken);
+                // Don't actually write any files since we're just getting diagnostics.
+                var writeFile = function () { };
+                return ts.getDeclarationDiagnostics(getEmitHost(writeFile), resolver, sourceFile);
             });
         }
+        function getDeclarationDiagnosticsForFile(sourceFile, cancellationToken) {
+            return ts.isDeclarationFile(sourceFile) ? [] : getDeclarationDiagnosticsWorker(sourceFile, cancellationToken);
+        }
         function getOptionsDiagnostics() {
             var allDiagnostics = [];
             ts.addRange(allDiagnostics, fileProcessingDiagnostics.getGlobalDiagnostics());