Fix semicolon-omitting writer

Author: andrewbranch

Diff for: 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 for: 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 for: 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 for: 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 for: tests/cases/fourslash/convertFunctionToEs6Class_objectLiteralInArrowFunction.ts

@@ -15,7 +15,7 @@ verify.codeFix({
     constructor() {
     }
     foo() {
-        ({ bar: () => { } });
+        ({ bar: () => { } })
     }
 }
 `,

Diff for: tests/cases/fourslash/extract-method25.ts

@@ -18,7 +18,7 @@ edit.applyRefactor({
     q[0]++
 
     function newFunction() {
-        return [0];
+        return [0]
     }
 }`
 });