diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index edb51cc59da..932677b526a 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -17738,7 +17738,7 @@ namespace ts {
             }
 
             if (node.kind === SyntaxKind.BindingElement) {
-                if (node.parent.kind === SyntaxKind.ObjectBindingPattern && languageVersion < ScriptTarget.ESNext && !isInAmbientContext(node)) {
+                if (node.parent.kind === SyntaxKind.ObjectBindingPattern && languageVersion < ScriptTarget.ESNext) {
                     checkExternalEmitHelpers(node, ExternalEmitHelpers.Rest);
                 }
                 // check computed properties inside property names of binding elements
@@ -18758,7 +18758,7 @@ namespace ts {
 
             const baseTypeNode = getClassExtendsHeritageClauseElement(node);
             if (baseTypeNode) {
-                if (languageVersion < ScriptTarget.ES2015 && !isInAmbientContext(node)) {
+                if (languageVersion < ScriptTarget.ES2015) {
                     checkExternalEmitHelpers(baseTypeNode.parent, ExternalEmitHelpers.Extends);
                 }
 
@@ -21287,7 +21287,7 @@ namespace ts {
         function checkExternalEmitHelpers(location: Node, helpers: ExternalEmitHelpers) {
             if ((requestedExternalEmitHelpers & helpers) !== helpers && compilerOptions.importHelpers) {
                 const sourceFile = getSourceFileOfNode(location);
-                if (!isDeclarationFile(sourceFile) && isEffectiveExternalModule(sourceFile, compilerOptions)) {
+                if (isEffectiveExternalModule(sourceFile, compilerOptions) && !isInAmbientContext(location)) {
                     const helpersModule = resolveHelpersModule(sourceFile, location);
                     if (helpersModule !== unknownSymbol) {
                         const uncheckedHelpers = helpers & ~requestedExternalEmitHelpers;
diff --git a/src/compiler/comments.ts b/src/compiler/comments.ts
index f252bfa5c5d..dcb471dcfcc 100644
--- a/src/compiler/comments.ts
+++ b/src/compiler/comments.ts
@@ -272,7 +272,7 @@ namespace ts {
 
         function forEachLeadingCommentToEmit(pos: number, cb: (commentPos: number, commentEnd: number, kind: SyntaxKind, hasTrailingNewLine: boolean, rangePos: number) => void) {
             // Emit the leading comments only if the container's pos doesn't match because the container should take care of emitting these comments
-            if ((containerPos === -1 || pos !== containerPos)) {
+            if (containerPos === -1 || pos !== containerPos) {
                 if (hasDetachedComments(pos)) {
                     forEachLeadingCommentWithoutDetachedComments(cb);
                 }
@@ -284,7 +284,7 @@ namespace ts {
 
         function forEachTrailingCommentToEmit(end: number, cb: (commentPos: number, commentEnd: number, kind: SyntaxKind, hasTrailingNewLine: boolean) => void) {
             // Emit the trailing comments only if the container's end doesn't match because the container should take care of emitting these comments
-            if ((containerEnd === -1 || (end !== containerEnd && end !== declarationListContainerEnd))) {
+            if (containerEnd === -1 || (end !== containerEnd && end !== declarationListContainerEnd)) {
                 forEachTrailingCommentRange(currentText, end, cb);
             }
         }