diff --git a/Gulpfile.ts b/Gulpfile.ts
index e025ce6eaa8..738ec107862 100644
--- a/Gulpfile.ts
+++ b/Gulpfile.ts
@@ -749,7 +749,7 @@ gulp.task("browserify", "Runs browserify on run.js to produce a file suitable fo
             const originalMap = file.sourceMap;
             const prebundledContent = file.contents.toString();
             // Make paths absolute to help sorcery deal with all the terrible paths being thrown around
-            originalMap.sources = originalMap.sources.map(s => path.resolve(s));
+            originalMap.sources = originalMap.sources.map(s => path.resolve(path.join("src/harness", s)));
             // intoStream (below) makes browserify think the input file is named this, so this is what it puts in the sourcemap
             originalMap.file = "built/local/_stream_0.js";
 
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index 5d585e2658a..f2175f385ec 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -3863,6 +3863,9 @@ namespace ts {
                     parseErrorAtPosition(openingTagName.pos, openingTagName.end - openingTagName.pos, Diagnostics.JSX_element_0_has_no_corresponding_closing_tag, getTextOfNodeFromSourceText(sourceText, openingTagName));
                     break;
                 }
+                else if (token() === SyntaxKind.ConflictMarkerTrivia) {
+                    break;
+                }
                 result.push(parseJsxChild());
             }
 
diff --git a/src/compiler/scanner.ts b/src/compiler/scanner.ts
index b7a3f35d728..466074bdbcc 100644
--- a/src/compiler/scanner.ts
+++ b/src/compiler/scanner.ts
@@ -1716,7 +1716,14 @@ namespace ts {
             while (pos < end) {
                 pos++;
                 char = text.charCodeAt(pos);
-                if ((char === CharacterCodes.openBrace) || (char === CharacterCodes.lessThan)) {
+                if (char === CharacterCodes.openBrace) {
+                    break;
+                }
+                if (char === CharacterCodes.lessThan) {
+                    if (isConflictMarkerTrivia(text, pos)) {
+                        pos = scanConflictMarkerTrivia(text, pos, error);
+                        return token = SyntaxKind.ConflictMarkerTrivia;
+                    }
                     break;
                 }
             }
diff --git a/src/compiler/sys.ts b/src/compiler/sys.ts
index 3f585900654..5275d210172 100644
--- a/src/compiler/sys.ts
+++ b/src/compiler/sys.ts
@@ -202,7 +202,7 @@ namespace ts {
                 if (len >= 2 && buffer[0] === 0xFE && buffer[1] === 0xFF) {
                     // Big endian UTF-16 byte order mark detected. Since big endian is not supported by node.js,
                     // flip all byte pairs and treat as little endian.
-                    len &= ~1;
+                    len &= ~1; // Round down to a multiple of 2
                     for (let i = 0; i < len; i += 2) {
                         const temp = buffer[i];
                         buffer[i] = buffer[i + 1];
diff --git a/src/compiler/transformers/module/module.ts b/src/compiler/transformers/module/module.ts
index 80a8c985c56..4ef9c674ad9 100644
--- a/src/compiler/transformers/module/module.ts
+++ b/src/compiler/transformers/module/module.ts
@@ -89,7 +89,8 @@ namespace ts {
             startLexicalEnvironment();
 
             const statements: Statement[] = [];
-            const statementOffset = addPrologueDirectives(statements, node.statements, /*ensureUseStrict*/ !compilerOptions.noImplicitUseStrict, sourceElementVisitor);
+            const ensureUseStrict = compilerOptions.alwaysStrict || (!compilerOptions.noImplicitUseStrict && isExternalModule(currentSourceFile));
+            const statementOffset = addPrologueDirectives(statements, node.statements, ensureUseStrict, sourceElementVisitor);
 
             if (shouldEmitUnderscoreUnderscoreESModule()) {
                 append(statements, createUnderscoreUnderscoreESModule());
diff --git a/src/compiler/transformers/module/system.ts b/src/compiler/transformers/module/system.ts
index 1a362c47fd1..642ac1ce6fb 100644
--- a/src/compiler/transformers/module/system.ts
+++ b/src/compiler/transformers/module/system.ts
@@ -225,7 +225,8 @@ namespace ts {
             startLexicalEnvironment();
 
             // Add any prologue directives.
-            const statementOffset = addPrologueDirectives(statements, node.statements, /*ensureUseStrict*/ !compilerOptions.noImplicitUseStrict, sourceElementVisitor);
+            const ensureUseStrict = compilerOptions.alwaysStrict || (!compilerOptions.noImplicitUseStrict && isExternalModule(currentSourceFile));
+            const statementOffset = addPrologueDirectives(statements, node.statements, ensureUseStrict, sourceElementVisitor);
 
             // var __moduleName = context_1 && context_1.id;
             statements.push(
diff --git a/src/harness/unittests/tsserverProjectSystem.ts b/src/harness/unittests/tsserverProjectSystem.ts
index a13835fa7f3..5ea0df91caa 100644
--- a/src/harness/unittests/tsserverProjectSystem.ts
+++ b/src/harness/unittests/tsserverProjectSystem.ts
@@ -3006,6 +3006,42 @@ namespace ts.projectSystem {
             const errorResult = <protocol.Diagnostic[]>session.executeCommand(dTsFileGetErrRequest).response;
             assert.isTrue(errorResult.length === 0);
         });
+
+        it("should be turned on for js-only external projects with skipLibCheck=false", () => {
+            const jsFile = {
+                path: "/a/b/file1.js",
+                content: "let x =1;"
+            };
+            const dTsFile = {
+                path: "/a/b/file2.d.ts",
+                content: `
+                interface T {
+                    name: string;
+                };
+                interface T {
+                    name: number;
+                };`
+            };
+            const host = createServerHost([jsFile, dTsFile]);
+            const session = createSession(host);
+
+            const openExternalProjectRequest = makeSessionRequest<protocol.OpenExternalProjectArgs>(
+                CommandNames.OpenExternalProject,
+                {
+                    projectFileName: "project1",
+                    rootFiles: toExternalFiles([jsFile.path, dTsFile.path]),
+                    options: { skipLibCheck: false }
+                }
+            );
+            session.executeCommand(openExternalProjectRequest);
+
+            const dTsFileGetErrRequest = makeSessionRequest<protocol.SemanticDiagnosticsSyncRequestArgs>(
+                CommandNames.SemanticDiagnosticsSync,
+                { file: dTsFile.path }
+            );
+            const errorResult = <protocol.Diagnostic[]>session.executeCommand(dTsFileGetErrRequest).response;
+            assert.isTrue(errorResult.length === 0);
+        });
     });
 
     describe("non-existing directories listed in config file input array", () => {
diff --git a/src/server/session.ts b/src/server/session.ts
index f82d11ba91b..8dd0411d077 100644
--- a/src/server/session.ts
+++ b/src/server/session.ts
@@ -26,14 +26,7 @@ namespace ts.server {
     }
 
     function shouldSkipSematicCheck(project: Project) {
-        if (project.getCompilerOptions().skipLibCheck !== undefined) {
-            return false;
-        }
-
-        if ((project.projectKind === ProjectKind.Inferred || project.projectKind === ProjectKind.External) && project.isJsOnlyProject()) {
-            return true;
-        }
-        return false;
+        return (project.projectKind === ProjectKind.Inferred || project.projectKind === ProjectKind.External) && project.isJsOnlyProject();
     }
 
     interface FileStart {
diff --git a/tests/baselines/reference/conflictMarkerTrivia3.errors.txt b/tests/baselines/reference/conflictMarkerTrivia3.errors.txt
new file mode 100644
index 00000000000..124201ce0ba
--- /dev/null
+++ b/tests/baselines/reference/conflictMarkerTrivia3.errors.txt
@@ -0,0 +1,15 @@
+tests/cases/compiler/conflictMarkerTrivia3.tsx(1,11): error TS17004: Cannot use JSX unless the '--jsx' flag is provided.
+tests/cases/compiler/conflictMarkerTrivia3.tsx(1,16): error TS1005: '</' expected.
+tests/cases/compiler/conflictMarkerTrivia3.tsx(2,1): error TS1185: Merge conflict marker encountered.
+
+
+==== tests/cases/compiler/conflictMarkerTrivia3.tsx (3 errors) ====
+    const x = <div>
+              ~~~~~
+!!! error TS17004: Cannot use JSX unless the '--jsx' flag is provided.
+                   
+    <<<<<<< HEAD
+    ~~~~~~~~~~~~
+!!! error TS1005: '</' expected.
+    ~~~~~~~
+!!! error TS1185: Merge conflict marker encountered.
\ No newline at end of file
diff --git a/tests/baselines/reference/conflictMarkerTrivia3.js b/tests/baselines/reference/conflictMarkerTrivia3.js
new file mode 100644
index 00000000000..804030522ec
--- /dev/null
+++ b/tests/baselines/reference/conflictMarkerTrivia3.js
@@ -0,0 +1,6 @@
+//// [conflictMarkerTrivia3.tsx]
+const x = <div>
+<<<<<<< HEAD
+
+//// [conflictMarkerTrivia3.js]
+var x = <div></>;
diff --git a/tests/baselines/reference/conflictMarkerTrivia4.errors.txt b/tests/baselines/reference/conflictMarkerTrivia4.errors.txt
new file mode 100644
index 00000000000..476dbbce6ce
--- /dev/null
+++ b/tests/baselines/reference/conflictMarkerTrivia4.errors.txt
@@ -0,0 +1,14 @@
+tests/cases/compiler/conflictMarkerTrivia4.ts(1,12): error TS2304: Cannot find name 'div'.
+tests/cases/compiler/conflictMarkerTrivia4.ts(2,1): error TS1185: Merge conflict marker encountered.
+tests/cases/compiler/conflictMarkerTrivia4.ts(2,13): error TS1109: Expression expected.
+
+
+==== tests/cases/compiler/conflictMarkerTrivia4.ts (3 errors) ====
+    const x = <div>
+               ~~~
+!!! error TS2304: Cannot find name 'div'.
+    <<<<<<< HEAD
+    ~~~~~~~
+!!! error TS1185: Merge conflict marker encountered.
+                
+!!! error TS1109: Expression expected.
\ No newline at end of file
diff --git a/tests/baselines/reference/conflictMarkerTrivia4.js b/tests/baselines/reference/conflictMarkerTrivia4.js
new file mode 100644
index 00000000000..945e82b2f2d
--- /dev/null
+++ b/tests/baselines/reference/conflictMarkerTrivia4.js
@@ -0,0 +1,6 @@
+//// [conflictMarkerTrivia4.ts]
+const x = <div>
+<<<<<<< HEAD
+
+//// [conflictMarkerTrivia4.js]
+var x = ;
diff --git a/tests/baselines/reference/importHelpersInIsolatedModules.js b/tests/baselines/reference/importHelpersInIsolatedModules.js
index 454fde430d3..26a9cafa188 100644
--- a/tests/baselines/reference/importHelpersInIsolatedModules.js
+++ b/tests/baselines/reference/importHelpersInIsolatedModules.js
@@ -68,7 +68,6 @@ C = tslib_1.__decorate([
     dec
 ], C);
 //// [script.js]
-"use strict";
 var tslib_1 = require("tslib");
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/isolatedModulesPlainFile-CommonJS.js b/tests/baselines/reference/isolatedModulesPlainFile-CommonJS.js
index f40d2173685..7026a7d9bed 100644
--- a/tests/baselines/reference/isolatedModulesPlainFile-CommonJS.js
+++ b/tests/baselines/reference/isolatedModulesPlainFile-CommonJS.js
@@ -5,5 +5,4 @@ run(1);
 
 
 //// [isolatedModulesPlainFile-CommonJS.js]
-"use strict";
 run(1);
diff --git a/tests/baselines/reference/isolatedModulesPlainFile-System.js b/tests/baselines/reference/isolatedModulesPlainFile-System.js
index 39b648e071a..43cad51d213 100644
--- a/tests/baselines/reference/isolatedModulesPlainFile-System.js
+++ b/tests/baselines/reference/isolatedModulesPlainFile-System.js
@@ -6,7 +6,6 @@ run(1);
 
 //// [isolatedModulesPlainFile-System.js]
 System.register([], function (exports_1, context_1) {
-    "use strict";
     var __moduleName = context_1 && context_1.id;
     return {
         setters: [],
diff --git a/tests/baselines/reference/transpile/Does not generate semantic diagnostics.js b/tests/baselines/reference/transpile/Does not generate semantic diagnostics.js
index 61a703e13bb..eb8be3556a1 100644
--- a/tests/baselines/reference/transpile/Does not generate semantic diagnostics.js	
+++ b/tests/baselines/reference/transpile/Does not generate semantic diagnostics.js	
@@ -1,3 +1,2 @@
-"use strict";
 var x = 0;
 //# sourceMappingURL=file.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Generates expected syntactic diagnostics.js b/tests/baselines/reference/transpile/Generates expected syntactic diagnostics.js
index 9d108d63313..c2c5134015c 100644
--- a/tests/baselines/reference/transpile/Generates expected syntactic diagnostics.js	
+++ b/tests/baselines/reference/transpile/Generates expected syntactic diagnostics.js	
@@ -1,4 +1,3 @@
-"use strict";
 a;
 b;
 //# sourceMappingURL=file.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Generates no diagnostics for missing file references.js b/tests/baselines/reference/transpile/Generates no diagnostics for missing file references.js
index 88d98628eee..9324d64de1e 100644
--- a/tests/baselines/reference/transpile/Generates no diagnostics for missing file references.js	
+++ b/tests/baselines/reference/transpile/Generates no diagnostics for missing file references.js	
@@ -1,4 +1,3 @@
-"use strict";
 /// <reference path="file2.ts" />
 var x = 0;
 //# sourceMappingURL=file.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Generates no diagnostics with valid inputs.js b/tests/baselines/reference/transpile/Generates no diagnostics with valid inputs.js
index 61a703e13bb..eb8be3556a1 100644
--- a/tests/baselines/reference/transpile/Generates no diagnostics with valid inputs.js	
+++ b/tests/baselines/reference/transpile/Generates no diagnostics with valid inputs.js	
@@ -1,3 +1,2 @@
-"use strict";
 var x = 0;
 //# sourceMappingURL=file.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Report an error when compiler-options module-kind is out-of-range.js b/tests/baselines/reference/transpile/Report an error when compiler-options module-kind is out-of-range.js
index 1ceb1bcd146..c7570e81192 100644
--- a/tests/baselines/reference/transpile/Report an error when compiler-options module-kind is out-of-range.js	
+++ b/tests/baselines/reference/transpile/Report an error when compiler-options module-kind is out-of-range.js	
@@ -1,2 +1 @@
-"use strict";
 //# sourceMappingURL=file.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Report an error when compiler-options target-script is out-of-range.js b/tests/baselines/reference/transpile/Report an error when compiler-options target-script is out-of-range.js
index 1ceb1bcd146..c7570e81192 100644
--- a/tests/baselines/reference/transpile/Report an error when compiler-options target-script is out-of-range.js	
+++ b/tests/baselines/reference/transpile/Report an error when compiler-options target-script is out-of-range.js	
@@ -1,2 +1 @@
-"use strict";
 //# sourceMappingURL=file.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Sets module name.js b/tests/baselines/reference/transpile/Sets module name.js
index dfe9605fc9e..72164ed6b16 100644
--- a/tests/baselines/reference/transpile/Sets module name.js	
+++ b/tests/baselines/reference/transpile/Sets module name.js	
@@ -1,5 +1,4 @@
 System.register("NamedModule", [], function (exports_1, context_1) {
-    "use strict";
     var __moduleName = context_1 && context_1.id;
     var x;
     return {
diff --git a/tests/baselines/reference/transpile/Support options with lib values.js b/tests/baselines/reference/transpile/Support options with lib values.js
index 36c68f08b9f..1c5faaae678 100644
--- a/tests/baselines/reference/transpile/Support options with lib values.js	
+++ b/tests/baselines/reference/transpile/Support options with lib values.js	
@@ -1,3 +1,2 @@
-"use strict";
 var a = 10;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Support options with types values.js b/tests/baselines/reference/transpile/Support options with types values.js
index 36c68f08b9f..1c5faaae678 100644
--- a/tests/baselines/reference/transpile/Support options with types values.js	
+++ b/tests/baselines/reference/transpile/Support options with types values.js	
@@ -1,3 +1,2 @@
-"use strict";
 var a = 10;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports backslashes in file name.js b/tests/baselines/reference/transpile/Supports backslashes in file name.js
index 942449753b0..7e5b546deba 100644
--- a/tests/baselines/reference/transpile/Supports backslashes in file name.js	
+++ b/tests/baselines/reference/transpile/Supports backslashes in file name.js	
@@ -1,3 +1,2 @@
-"use strict";
 var x;
 //# sourceMappingURL=b.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting allowJs.js b/tests/baselines/reference/transpile/Supports setting allowJs.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting allowJs.js	
+++ b/tests/baselines/reference/transpile/Supports setting allowJs.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting allowSyntheticDefaultImports.js b/tests/baselines/reference/transpile/Supports setting allowSyntheticDefaultImports.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting allowSyntheticDefaultImports.js	
+++ b/tests/baselines/reference/transpile/Supports setting allowSyntheticDefaultImports.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting allowUnreachableCode.js b/tests/baselines/reference/transpile/Supports setting allowUnreachableCode.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting allowUnreachableCode.js	
+++ b/tests/baselines/reference/transpile/Supports setting allowUnreachableCode.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting allowUnusedLabels.js b/tests/baselines/reference/transpile/Supports setting allowUnusedLabels.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting allowUnusedLabels.js	
+++ b/tests/baselines/reference/transpile/Supports setting allowUnusedLabels.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting baseUrl.js b/tests/baselines/reference/transpile/Supports setting baseUrl.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting baseUrl.js	
+++ b/tests/baselines/reference/transpile/Supports setting baseUrl.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting charset.js b/tests/baselines/reference/transpile/Supports setting charset.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting charset.js	
+++ b/tests/baselines/reference/transpile/Supports setting charset.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting declaration.js b/tests/baselines/reference/transpile/Supports setting declaration.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting declaration.js	
+++ b/tests/baselines/reference/transpile/Supports setting declaration.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting declarationDir.js b/tests/baselines/reference/transpile/Supports setting declarationDir.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting declarationDir.js	
+++ b/tests/baselines/reference/transpile/Supports setting declarationDir.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting emitBOM.js b/tests/baselines/reference/transpile/Supports setting emitBOM.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting emitBOM.js	
+++ b/tests/baselines/reference/transpile/Supports setting emitBOM.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting emitDecoratorMetadata.js b/tests/baselines/reference/transpile/Supports setting emitDecoratorMetadata.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting emitDecoratorMetadata.js	
+++ b/tests/baselines/reference/transpile/Supports setting emitDecoratorMetadata.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting experimentalDecorators.js b/tests/baselines/reference/transpile/Supports setting experimentalDecorators.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting experimentalDecorators.js	
+++ b/tests/baselines/reference/transpile/Supports setting experimentalDecorators.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting forceConsistentCasingInFileNames.js b/tests/baselines/reference/transpile/Supports setting forceConsistentCasingInFileNames.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting forceConsistentCasingInFileNames.js	
+++ b/tests/baselines/reference/transpile/Supports setting forceConsistentCasingInFileNames.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting isolatedModules.js b/tests/baselines/reference/transpile/Supports setting isolatedModules.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting isolatedModules.js	
+++ b/tests/baselines/reference/transpile/Supports setting isolatedModules.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting jsx.js b/tests/baselines/reference/transpile/Supports setting jsx.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting jsx.js	
+++ b/tests/baselines/reference/transpile/Supports setting jsx.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting jsxFactory.js b/tests/baselines/reference/transpile/Supports setting jsxFactory.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting jsxFactory.js	
+++ b/tests/baselines/reference/transpile/Supports setting jsxFactory.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting lib.js b/tests/baselines/reference/transpile/Supports setting lib.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting lib.js	
+++ b/tests/baselines/reference/transpile/Supports setting lib.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting locale.js b/tests/baselines/reference/transpile/Supports setting locale.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting locale.js	
+++ b/tests/baselines/reference/transpile/Supports setting locale.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting module.js b/tests/baselines/reference/transpile/Supports setting module.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting module.js	
+++ b/tests/baselines/reference/transpile/Supports setting module.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting moduleResolution.js b/tests/baselines/reference/transpile/Supports setting moduleResolution.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting moduleResolution.js	
+++ b/tests/baselines/reference/transpile/Supports setting moduleResolution.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting newLine.js b/tests/baselines/reference/transpile/Supports setting newLine.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting newLine.js	
+++ b/tests/baselines/reference/transpile/Supports setting newLine.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting noEmit.js b/tests/baselines/reference/transpile/Supports setting noEmit.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting noEmit.js	
+++ b/tests/baselines/reference/transpile/Supports setting noEmit.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting noEmitHelpers.js b/tests/baselines/reference/transpile/Supports setting noEmitHelpers.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting noEmitHelpers.js	
+++ b/tests/baselines/reference/transpile/Supports setting noEmitHelpers.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting noEmitOnError.js b/tests/baselines/reference/transpile/Supports setting noEmitOnError.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting noEmitOnError.js	
+++ b/tests/baselines/reference/transpile/Supports setting noEmitOnError.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting noErrorTruncation.js b/tests/baselines/reference/transpile/Supports setting noErrorTruncation.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting noErrorTruncation.js	
+++ b/tests/baselines/reference/transpile/Supports setting noErrorTruncation.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting noFallthroughCasesInSwitch.js b/tests/baselines/reference/transpile/Supports setting noFallthroughCasesInSwitch.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting noFallthroughCasesInSwitch.js	
+++ b/tests/baselines/reference/transpile/Supports setting noFallthroughCasesInSwitch.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting noImplicitAny.js b/tests/baselines/reference/transpile/Supports setting noImplicitAny.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting noImplicitAny.js	
+++ b/tests/baselines/reference/transpile/Supports setting noImplicitAny.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting noImplicitReturns.js b/tests/baselines/reference/transpile/Supports setting noImplicitReturns.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting noImplicitReturns.js	
+++ b/tests/baselines/reference/transpile/Supports setting noImplicitReturns.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting noImplicitThis.js b/tests/baselines/reference/transpile/Supports setting noImplicitThis.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting noImplicitThis.js	
+++ b/tests/baselines/reference/transpile/Supports setting noImplicitThis.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting noLib.js b/tests/baselines/reference/transpile/Supports setting noLib.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting noLib.js	
+++ b/tests/baselines/reference/transpile/Supports setting noLib.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting noResolve.js b/tests/baselines/reference/transpile/Supports setting noResolve.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting noResolve.js	
+++ b/tests/baselines/reference/transpile/Supports setting noResolve.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting out.js b/tests/baselines/reference/transpile/Supports setting out.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting out.js	
+++ b/tests/baselines/reference/transpile/Supports setting out.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting outDir.js b/tests/baselines/reference/transpile/Supports setting outDir.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting outDir.js	
+++ b/tests/baselines/reference/transpile/Supports setting outDir.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting outFile.js b/tests/baselines/reference/transpile/Supports setting outFile.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting outFile.js	
+++ b/tests/baselines/reference/transpile/Supports setting outFile.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting paths.js b/tests/baselines/reference/transpile/Supports setting paths.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting paths.js	
+++ b/tests/baselines/reference/transpile/Supports setting paths.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting preserveConstEnums.js b/tests/baselines/reference/transpile/Supports setting preserveConstEnums.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting preserveConstEnums.js	
+++ b/tests/baselines/reference/transpile/Supports setting preserveConstEnums.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting reactNamespace.js b/tests/baselines/reference/transpile/Supports setting reactNamespace.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting reactNamespace.js	
+++ b/tests/baselines/reference/transpile/Supports setting reactNamespace.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting removeComments.js b/tests/baselines/reference/transpile/Supports setting removeComments.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting removeComments.js	
+++ b/tests/baselines/reference/transpile/Supports setting removeComments.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting rootDir.js b/tests/baselines/reference/transpile/Supports setting rootDir.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting rootDir.js	
+++ b/tests/baselines/reference/transpile/Supports setting rootDir.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting rootDirs.js b/tests/baselines/reference/transpile/Supports setting rootDirs.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting rootDirs.js	
+++ b/tests/baselines/reference/transpile/Supports setting rootDirs.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting skipDefaultLibCheck.js b/tests/baselines/reference/transpile/Supports setting skipDefaultLibCheck.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting skipDefaultLibCheck.js	
+++ b/tests/baselines/reference/transpile/Supports setting skipDefaultLibCheck.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting skipLibCheck.js b/tests/baselines/reference/transpile/Supports setting skipLibCheck.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting skipLibCheck.js	
+++ b/tests/baselines/reference/transpile/Supports setting skipLibCheck.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting strictNullChecks.js b/tests/baselines/reference/transpile/Supports setting strictNullChecks.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting strictNullChecks.js	
+++ b/tests/baselines/reference/transpile/Supports setting strictNullChecks.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting stripInternal.js b/tests/baselines/reference/transpile/Supports setting stripInternal.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting stripInternal.js	
+++ b/tests/baselines/reference/transpile/Supports setting stripInternal.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting suppressExcessPropertyErrors.js b/tests/baselines/reference/transpile/Supports setting suppressExcessPropertyErrors.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting suppressExcessPropertyErrors.js	
+++ b/tests/baselines/reference/transpile/Supports setting suppressExcessPropertyErrors.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting suppressImplicitAnyIndexErrors.js b/tests/baselines/reference/transpile/Supports setting suppressImplicitAnyIndexErrors.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting suppressImplicitAnyIndexErrors.js	
+++ b/tests/baselines/reference/transpile/Supports setting suppressImplicitAnyIndexErrors.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting typeRoots.js b/tests/baselines/reference/transpile/Supports setting typeRoots.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting typeRoots.js	
+++ b/tests/baselines/reference/transpile/Supports setting typeRoots.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting types.js b/tests/baselines/reference/transpile/Supports setting types.js
index 8d91090453b..8394371f908 100644
--- a/tests/baselines/reference/transpile/Supports setting types.js	
+++ b/tests/baselines/reference/transpile/Supports setting types.js	
@@ -1,3 +1,2 @@
-"use strict";
 x;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports urls in file name.js b/tests/baselines/reference/transpile/Supports urls in file name.js
index 3923d3c9a41..50fa840c62e 100644
--- a/tests/baselines/reference/transpile/Supports urls in file name.js	
+++ b/tests/baselines/reference/transpile/Supports urls in file name.js	
@@ -1,3 +1,2 @@
-"use strict";
 var x;
 //# sourceMappingURL=file.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Uses correct newLine character.js b/tests/baselines/reference/transpile/Uses correct newLine character.js
index bab9c3c4443..976498c2da8 100644
--- a/tests/baselines/reference/transpile/Uses correct newLine character.js	
+++ b/tests/baselines/reference/transpile/Uses correct newLine character.js	
@@ -1,3 +1,2 @@
-"use strict";
 var x = 0;
 //# sourceMappingURL=file.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/transpile .js files.js b/tests/baselines/reference/transpile/transpile .js files.js
index c17099d84ba..36551461def 100644
--- a/tests/baselines/reference/transpile/transpile .js files.js	
+++ b/tests/baselines/reference/transpile/transpile .js files.js	
@@ -1,3 +1,2 @@
-"use strict";
 var a = 10;
 //# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/transpile file as tsx if jsx is specified.js b/tests/baselines/reference/transpile/transpile file as tsx if jsx is specified.js
index baa27ee64ce..8620309214f 100644
--- a/tests/baselines/reference/transpile/transpile file as tsx if jsx is specified.js	
+++ b/tests/baselines/reference/transpile/transpile file as tsx if jsx is specified.js	
@@ -1,3 +1,2 @@
-"use strict";
 var x = React.createElement("div", null);
 //# sourceMappingURL=file.js.map
\ No newline at end of file
diff --git a/tests/cases/compiler/conflictMarkerTrivia3.tsx b/tests/cases/compiler/conflictMarkerTrivia3.tsx
new file mode 100644
index 00000000000..21f83715ad0
--- /dev/null
+++ b/tests/cases/compiler/conflictMarkerTrivia3.tsx
@@ -0,0 +1,2 @@
+const x = <div>
+<<<<<<< HEAD
\ No newline at end of file
diff --git a/tests/cases/compiler/conflictMarkerTrivia4.ts b/tests/cases/compiler/conflictMarkerTrivia4.ts
new file mode 100644
index 00000000000..21f83715ad0
--- /dev/null
+++ b/tests/cases/compiler/conflictMarkerTrivia4.ts
@@ -0,0 +1,2 @@
+const x = <div>
+<<<<<<< HEAD
\ No newline at end of file