feat(lsp): auto-import types with 'import type' (#25662)

1 files changed, 34 insertions, 5 deletions

diff --git a/cli/tsc/99_main_compiler.js b/cli/tsc/99_main_compiler.js
index 7fac8cd35..c5769168f 100644
--- a/cli/tsc/99_main_compiler.js
+++ b/cli/tsc/99_main_compiler.js
@@ -516,6 +516,7 @@ delete Object.prototype.__proto__;
   /** @typedef {{
    *    ls: ts.LanguageService & { [k:string]: any },
    *    compilerOptions: ts.CompilerOptions,
+   *    forceEnabledVerbatimModuleSyntax: boolean,
    *  }} LanguageServiceEntry */
   /** @type {{ unscoped: LanguageServiceEntry, byScope: Map<string, LanguageServiceEntry> }} */
   const languageServiceEntries = {
@@ -1025,7 +1026,7 @@ delete Object.prototype.__proto__;
         : ts.sortAndDeduplicateDiagnostics(
           checkFiles.map((s) => program.getSemanticDiagnostics(s)).flat(),
         )),
-    ].filter(filterMapDiagnostic);
+    ].filter(filterMapDiagnostic.bind(null, false));
 
     // emit the tsbuildinfo file
     // @ts-ignore: emitBuildInfo is not exposed (https://github.com/microsoft/TypeScript/issues/49871)
@@ -1040,11 +1041,28 @@ delete Object.prototype.__proto__;
     debug("<<< exec stop");
   }
 
-  /** @param {ts.Diagnostic} diagnostic */
-  function filterMapDiagnostic(diagnostic) {
+  /**
+   * @param {boolean} isLsp
+   * @param {ts.Diagnostic} diagnostic
+   */
+  function filterMapDiagnostic(isLsp, diagnostic) {
     if (IGNORED_DIAGNOSTICS.includes(diagnostic.code)) {
       return false;
     }
+    if (isLsp) {
+      // TS1484: `...` is a type and must be imported using a type-only import when 'verbatimModuleSyntax' is enabled.
+      // We force-enable `verbatimModuleSyntax` in the LSP so the `type`
+      // modifier is used when auto-importing types. But we don't want this
+      // diagnostic unless it was explicitly enabled by the user.
+      if (diagnostic.code == 1484) {
+        const entry = (lastRequestScope
+          ? languageServiceEntries.byScope.get(lastRequestScope)
+          : null) ?? languageServiceEntries.unscoped;
+        if (entry.forceEnabledVerbatimModuleSyntax) {
+          return false;
+        }
+      }
+    }
     // make the diagnostic for using an `export =` in an es module a warning
     if (diagnostic.code === 1203) {
       diagnostic.category = ts.DiagnosticCategory.Warning;
@@ -1140,10 +1158,12 @@ delete Object.prototype.__proto__;
         "strict": true,
         "target": "esnext",
         "useDefineForClassFields": true,
+        "verbatimModuleSyntax": true,
         "jsx": "react",
         "jsxFactory": "React.createElement",
         "jsxFragmentFactory": "React.Fragment",
       }),
+      forceEnabledVerbatimModuleSyntax: true,
     };
     setLogDebug(enableDebugLogging, "TSLS");
     debug("serverInit()");
@@ -1209,8 +1229,17 @@ delete Object.prototype.__proto__;
           const ls = oldEntry
             ? oldEntry.ls
             : ts.createLanguageService(host, documentRegistry);
+          let forceEnabledVerbatimModuleSyntax = false;
+          if (!config["verbatimModuleSyntax"]) {
+            config["verbatimModuleSyntax"] = true;
+            forceEnabledVerbatimModuleSyntax = true;
+          }
           const compilerOptions = lspTsConfigToCompilerOptions(config);
-          newByScope.set(scope, { ls, compilerOptions });
+          newByScope.set(scope, {
+            ls,
+            compilerOptions,
+            forceEnabledVerbatimModuleSyntax,
+          });
           languageServiceEntries.byScope.delete(scope);
         }
         for (const oldEntry of languageServiceEntries.byScope.values()) {
@@ -1275,7 +1304,7 @@ delete Object.prototype.__proto__;
               ...ls.getSemanticDiagnostics(specifier),
               ...ls.getSuggestionDiagnostics(specifier),
               ...ls.getSyntacticDiagnostics(specifier),
-            ].filter(filterMapDiagnostic));
+            ].filter(filterMapDiagnostic.bind(null, true)));
           }
           return respond(id, diagnosticMap);
         } catch (e) {