Remove lib file errors when all files are to be emitted.

Fixes #26389

src/compiler/builder.ts

@@ -38,6 +38,10 @@ namespace ts {
          * Already seen affected files
          */
         seenAffectedFiles: Map<true> | undefined;
+        /**
+         * program corresponding to this state
+         */
+        cleanedDiagnosticsOfLibFiles?: boolean;
         /**
          * True if the semantic diagnostics were copied from the old state
          */
@@ -83,6 +87,8 @@ namespace ts {
         // Update changed files and copy semantic diagnostics if we can
         const referencedMap = state.referencedMap;
         const oldReferencedMap = useOldState ? oldState!.referencedMap : undefined;
+        const copyDeclarationFileDiagnostics = canCopySemanticDiagnostics && !compilerOptions.skipLibCheck === !oldState!.program.getCompilerOptions().skipLibCheck;
+        const copyLibFileDiagnostics = copyDeclarationFileDiagnostics && !compilerOptions.skipDefaultLibCheck === !oldState!.program.getCompilerOptions().skipDefaultLibCheck;
         state.fileInfos.forEach((info, sourceFilePath) => {
             let oldInfo: Readonly<BuilderState.FileInfo> | undefined;
             let newReferences: BuilderState.ReferencedSet | undefined;
@@ -101,6 +107,11 @@ namespace ts {
                 state.changedFilesSet.set(sourceFilePath, true);
             }
             else if (canCopySemanticDiagnostics) {
+                const sourceFile = state.program.getSourceFileByPath(sourceFilePath as Path)!;
+
+                if (sourceFile.isDeclarationFile && !copyDeclarationFileDiagnostics) { return; }
+                if (sourceFile.hasNoDefaultLib && !copyLibFileDiagnostics) { return; }
+
                 // Unchanged file copy diagnostics
                 const diagnostics = oldState!.semanticDiagnosticsPerFile!.get(sourceFilePath);
                 if (diagnostics) {
@@ -193,6 +204,19 @@ namespace ts {
             return;
         }
 
+        // Clean lib file diagnostics if its all files excluding default files to emit
+        if (state.allFilesExcludingDefaultLibraryFile === state.affectedFiles && !state.cleanedDiagnosticsOfLibFiles) {
+            state.cleanedDiagnosticsOfLibFiles = true;
+            const options = state.program.getCompilerOptions();
+            if (forEach(state.program.getSourceFiles(), f =>
+                !contains(state.allFilesExcludingDefaultLibraryFile, f) &&
+                !skipTypeChecking(f, options) &&
+                removeSemanticDiagnosticsOf(state, f.path)
+            )) {
+                return;
+            }
+        }
+
         // If there was change in signature for the changed file,
         // then delete the semantic diagnostics for files that are affected by using exports of this module
 
@@ -268,7 +292,7 @@ namespace ts {
      */
     function removeSemanticDiagnosticsOf(state: BuilderProgramState, path: Path) {
         if (!state.semanticDiagnosticsFromOldState) {
-            return false;
+            return true;
         }
         state.semanticDiagnosticsFromOldState.delete(path);
         state.semanticDiagnosticsPerFile!.delete(path);

src/testRunner/unittests/tscWatchMode.ts

@@ -1564,6 +1564,125 @@ export class Data2 {
                 verifyTransitiveExports([libFile, app, lib2Public, lib2Data, lib2Data2, lib1Public, lib1ToolsPublic, lib1ToolsInterface]);
             });
         });
+
+        describe("updates errors in lib file when non module file changes", () => {
+            const currentDirectory = "/user/username/projects/myproject";
+            const field = "fullscreen";
+            const aFile: File = {
+                path: `${currentDirectory}/a.ts`,
+                content: `interface Document {
+	${field}: boolean;
+}`
+            };
+            const libFileWithDocument: File = {
+                path: libFile.path,
+                content: `${libFile.content}
+interface Document {
+    readonly ${field}: boolean;
+}`
+            };
+
+            function getDiagnostic(program: Program, file: File) {
+                return getDiagnosticOfFileFromProgram(program, file.path, file.content.indexOf(field), field.length, Diagnostics.All_declarations_of_0_must_have_identical_modifiers, field);
+            }
+
+            const files = [aFile, libFileWithDocument];
+
+            function verifyLibErrors(options: CompilerOptions) {
+                const host = createWatchedSystem(files, { currentDirectory });
+                const watch = createWatchOfFilesAndCompilerOptions([aFile.path], host, options);
+                checkProgramActualFiles(watch(), [aFile.path, libFile.path]);
+                checkOutputErrorsInitial(host, getErrors());
+
+                host.writeFile(aFile.path, "var x = 10;");
+                host.runQueuedTimeoutCallbacks();
+                checkProgramActualFiles(watch(), [aFile.path, libFile.path]);
+                checkOutputErrorsIncremental(host, emptyArray);
+
+                host.writeFile(aFile.path, aFile.content);
+                host.runQueuedTimeoutCallbacks();
+                checkProgramActualFiles(watch(), [aFile.path, libFile.path]);
+                checkOutputErrorsIncremental(host, getErrors());
+
+                function getErrors() {
+                    return [
+                        ...(options.skipLibCheck || options.skipDefaultLibCheck ? [] : [getDiagnostic(watch(), libFileWithDocument)]),
+                        getDiagnostic(watch(), aFile)
+                    ];
+                }
+            }
+
+            it("with default options", () => {
+                verifyLibErrors({});
+            });
+            it("with skipLibCheck", () => {
+                verifyLibErrors({ skipLibCheck: true });
+            });
+            it("with skipDefaultLibCheck", () => {
+                verifyLibErrors({ skipDefaultLibCheck: true });
+            });
+        });
+
+        it("when skipLibCheck and skipDefaultLibCheck changes", () => {
+            const currentDirectory = "/user/username/projects/myproject";
+            const field = "fullscreen";
+            const aFile: File = {
+                path: `${currentDirectory}/a.ts`,
+                content: `interface Document {
+	${field}: boolean;
+}`
+            };
+            const bFile: File = {
+                path: `${currentDirectory}/b.d.ts`,
+                content: `interface Document {
+	${field}: boolean;
+}`
+            };
+            const libFileWithDocument: File = {
+                path: libFile.path,
+                content: `${libFile.content}
+interface Document {
+    readonly ${field}: boolean;
+}`
+            };
+            const configFile: File = {
+                path: `${currentDirectory}/tsconfig.json`,
+                content: "{}"
+            };
+
+            const files = [aFile, bFile, configFile, libFileWithDocument];
+
+            const host = createWatchedSystem(files, { currentDirectory });
+            const watch = createWatchOfConfigFile("tsconfig.json", host);
+            verifyProgramFiles();
+            checkOutputErrorsInitial(host, [
+                getDiagnostic(libFileWithDocument),
+                getDiagnostic(aFile),
+                getDiagnostic(bFile)
+            ]);
+
+            verifyConfigChange({ skipLibCheck: true }, [aFile]);
+            verifyConfigChange({ skipDefaultLibCheck: true }, [aFile, bFile]);
+            verifyConfigChange({}, [libFileWithDocument, aFile, bFile]);
+            verifyConfigChange({ skipDefaultLibCheck: true }, [aFile, bFile]);
+            verifyConfigChange({ skipLibCheck: true }, [aFile]);
+            verifyConfigChange({}, [libFileWithDocument, aFile, bFile]);
+
+            function verifyConfigChange(compilerOptions: CompilerOptions, errorInFiles: ReadonlyArray<File>) {
+                host.writeFile(configFile.path, JSON.stringify({ compilerOptions }));
+                host.runQueuedTimeoutCallbacks();
+                verifyProgramFiles();
+                checkOutputErrorsIncremental(host, errorInFiles.map(getDiagnostic));
+            }
+
+            function getDiagnostic(file: File) {
+                return getDiagnosticOfFileFromProgram(watch(), file.path, file.content.indexOf(field), field.length, Diagnostics.All_declarations_of_0_must_have_identical_modifiers, field);
+            }
+
+            function verifyProgramFiles() {
+                checkProgramActualFiles(watch(), [aFile.path, bFile.path, libFile.path]);
+            }
+        });
     });
 
     describe("tsc-watch emit with outFile or out setting", () => {