From 8dbbf1174459305c2c85f59fc952c77d52935ddc Mon Sep 17 00:00:00 2001
From: Andrew Branch <andrew@wheream.io>
Date: Wed, 14 Aug 2019 16:30:20 -0700
Subject: [PATCH 1/2] Fix semicolon-omitting writer

---
 src/compiler/checker.ts                       |  2 +-
 src/compiler/emitter.ts                       |  2 +-
 src/compiler/utilities.ts                     | 20 ++++++++++++++++++-
 src/services/textChanges.ts                   |  2 +-
 ...ToEs6Class_objectLiteralInArrowFunction.ts |  2 +-
 tests/cases/fourslash/extract-method25.ts     |  2 +-
 6 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 9d6fa60306c03..0bcc8cf699fef 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -3506,7 +3506,7 @@ namespace ts {
                 const sig = nodeBuilder.signatureToSignatureDeclaration(signature, sigOutput, enclosingDeclaration, toNodeBuilderFlags(flags) | NodeBuilderFlags.IgnoreErrors | NodeBuilderFlags.WriteTypeParametersInQualifiedName);
                 const printer = createPrinter({ removeComments: true, omitTrailingSemicolon: true });
                 const sourceFile = enclosingDeclaration && getSourceFileOfNode(enclosingDeclaration);
-                printer.writeNode(EmitHint.Unspecified, sig!, /*sourceFile*/ sourceFile, getTrailingSemicolonOmittingWriter(writer)); // TODO: GH#18217
+                printer.writeNode(EmitHint.Unspecified, sig!, /*sourceFile*/ sourceFile, getTrailingSemicolonDeferringWriter(writer)); // TODO: GH#18217
                 return writer;
             }
         }
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index a70973825d1a0..fbdf000cf240a 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -1056,7 +1056,7 @@ namespace ts {
 
         function setWriter(_writer: EmitTextWriter | undefined, _sourceMapGenerator: SourceMapGenerator | undefined) {
             if (_writer && printerOptions.omitTrailingSemicolon) {
-                _writer = getTrailingSemicolonOmittingWriter(_writer);
+                _writer = getTrailingSemicolonDeferringWriter(_writer);
             }
 
             writer = _writer!; // TODO: GH#18217
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 0bb3c799af5fd..806c533792408 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -3369,7 +3369,11 @@ namespace ts {
         };
     }
 
-    export function getTrailingSemicolonOmittingWriter(writer: EmitTextWriter): EmitTextWriter {
+    export interface TrailingSemicolonDeferringWriter extends EmitTextWriter {
+        resetPendingTrailingSemicolon(): void;
+    }
+
+    export function getTrailingSemicolonDeferringWriter(writer: EmitTextWriter): TrailingSemicolonDeferringWriter {
         let pendingTrailingSemicolon = false;
 
         function commitPendingTrailingSemicolon() {
@@ -3435,10 +3439,24 @@ namespace ts {
             decreaseIndent() {
                 commitPendingTrailingSemicolon();
                 writer.decreaseIndent();
+            },
+            resetPendingTrailingSemicolon() {
+                pendingTrailingSemicolon = false;
             }
         };
     }
 
+    export function getTrailingSemicolonOmittingWriter(writer: EmitTextWriter): EmitTextWriter {
+        const deferringWriter = getTrailingSemicolonDeferringWriter(writer);
+        return {
+            ...deferringWriter,
+            writeLine() {
+                deferringWriter.resetPendingTrailingSemicolon();
+                writer.writeLine();
+            },
+        };
+    }
+
     export function getResolvedExternalModuleName(host: EmitHost, file: SourceFile, referenceFile?: SourceFile): string {
         return file.moduleName || getExternalModuleNameFromPath(host, file.fileName, referenceFile && referenceFile.fileName);
     }
diff --git a/src/services/textChanges.ts b/src/services/textChanges.ts
index f3e5bf9bfb57d..31c9f9f26717b 100644
--- a/src/services/textChanges.ts
+++ b/src/services/textChanges.ts
@@ -854,7 +854,7 @@ namespace ts.textChanges {
             const omitTrailingSemicolon = !!sourceFile && !probablyUsesSemicolons(sourceFile);
             const writer = createWriter(newLineCharacter, omitTrailingSemicolon);
             const newLine = newLineCharacter === "\n" ? NewLineKind.LineFeed : NewLineKind.CarriageReturnLineFeed;
-            createPrinter({ newLine, neverAsciiEscape: true, omitTrailingSemicolon }, writer).writeNode(EmitHint.Unspecified, node, sourceFile, writer);
+            createPrinter({ newLine, neverAsciiEscape: true }, writer).writeNode(EmitHint.Unspecified, node, sourceFile, writer);
             return { text: writer.getText(), node: assignPositionsToNode(node) };
         }
     }
diff --git a/tests/cases/fourslash/convertFunctionToEs6Class_objectLiteralInArrowFunction.ts b/tests/cases/fourslash/convertFunctionToEs6Class_objectLiteralInArrowFunction.ts
index a86af1e6d3d29..93bbd707dde14 100644
--- a/tests/cases/fourslash/convertFunctionToEs6Class_objectLiteralInArrowFunction.ts
+++ b/tests/cases/fourslash/convertFunctionToEs6Class_objectLiteralInArrowFunction.ts
@@ -15,7 +15,7 @@ verify.codeFix({
     constructor() {
     }
     foo() {
-        ({ bar: () => { } });
+        ({ bar: () => { } })
     }
 }
 `,
diff --git a/tests/cases/fourslash/extract-method25.ts b/tests/cases/fourslash/extract-method25.ts
index a06262ca47510..3aecc128e6efc 100644
--- a/tests/cases/fourslash/extract-method25.ts
+++ b/tests/cases/fourslash/extract-method25.ts
@@ -18,7 +18,7 @@ edit.applyRefactor({
     q[0]++
 
     function newFunction() {
-        return [0];
+        return [0]
     }
 }`
 });

From 62bfb060e757b5494248b29641d65567aee49e18 Mon Sep 17 00:00:00 2001
From: Andrew Branch <andrew@wheream.io>
Date: Wed, 28 Aug 2019 13:36:44 -0700
Subject: [PATCH 2/2] Use writeTrailingSemicolon for do statements

---
 src/compiler/emitter.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index fbdf000cf240a..5766eba18668f 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -2514,7 +2514,7 @@ namespace ts {
             }
 
             emitWhileClause(node, node.statement.end);
-            writePunctuation(";");
+            writeTrailingSemicolon();
         }
 
         function emitWhileStatement(node: WhileStatement) {