Add codefix and completions for promoting existing type-only imports to non-type-only

src/compiler/diagnosticMessages.json

@@ -6466,6 +6466,14 @@
         "category": "Message",
         "code": 90054
     },
+    "Remove 'type' from import declaration from \"{0}\"": {
+        "category": "Message",
+        "code": 90055
+    },
+    "Remove 'type' from import of '{0}' from \"{1}\"": {
+        "category": "Message",
+        "code": 90056
+    },
 
     "Convert function to an ES2015 class": {
         "category": "Message",

src/compiler/types.ts

@@ -3141,8 +3141,8 @@ namespace ts {
         | ImportClause & { readonly isTypeOnly: true, readonly name: Identifier }
         | ImportEqualsDeclaration & { readonly isTypeOnly: true }
         | NamespaceImport & { readonly parent: ImportClause & { readonly isTypeOnly: true } }
-        | ImportSpecifier & { readonly parent: NamedImports & { readonly parent: ImportClause & { readonly isTypeOnly: true } } }
-        | ExportSpecifier & { readonly parent: NamedExports & { readonly parent: ExportDeclaration & { readonly isTypeOnly: true } } }
+        | ImportSpecifier & ({ readonly isTypeOnly: true } | { readonly parent: NamedImports & { readonly parent: ImportClause & { readonly isTypeOnly: true } } })
+        | ExportSpecifier & ({ readonly isTypeOnly: true } | { readonly parent: NamedExports & { readonly parent: ExportDeclaration & { readonly isTypeOnly: true } } })
         ;
 
     /**

src/services/completions.ts

@@ -60,6 +60,8 @@ namespace ts.Completions {
         ThisProperty = "ThisProperty/",
         /** Auto-import that comes attached to a class member snippet */
         ClassMemberSnippet = "ClassMemberSnippet/",
+        /** A type-only import that needs to be promoted in order to be used at the completion location */
+        TypeOnlyAlias = "TypeOnlyAlias/",
     }
 
     const enum SymbolOriginInfoKind {
@@ -69,6 +71,7 @@ namespace ts.Completions {
         Promise             = 1 << 3,
         Nullable            = 1 << 4,
         ResolvedExport      = 1 << 5,
+        TypeOnlyAlias       = 1 << 6,
 
         SymbolMemberNoExport = SymbolMember,
         SymbolMemberExport   = SymbolMember | Export,
@@ -96,6 +99,10 @@ namespace ts.Completions {
         moduleSpecifier: string;
     }
 
+    interface SymbolOriginInfoTypeOnlyAlias extends SymbolOriginInfo {
+        declaration: TypeOnlyAliasDeclaration;
+    }
+
     function originIsThisType(origin: SymbolOriginInfo): boolean {
         return !!(origin.kind & SymbolOriginInfoKind.ThisType);
     }
@@ -128,6 +135,10 @@ namespace ts.Completions {
         return !!(origin.kind & SymbolOriginInfoKind.Nullable);
     }
 
+    function originIsTypeOnlyAlias(origin: SymbolOriginInfo | undefined): origin is SymbolOriginInfoTypeOnlyAlias {
+        return !!(origin && origin.kind & SymbolOriginInfoKind.TypeOnlyAlias);
+    }
+
     interface UniqueNameSet {
         add(name: string): void;
         has(name: string): boolean;
@@ -740,6 +751,10 @@ namespace ts.Completions {
             }
         }
 
+        if (origin?.kind === SymbolOriginInfoKind.TypeOnlyAlias) {
+            hasAction = true;
+        }
+
         if (preferences.includeCompletionsWithClassMemberSnippets &&
             preferences.includeCompletionsWithInsertText &&
             completionKind === CompletionKind.MemberLike &&
@@ -1168,6 +1183,9 @@ namespace ts.Completions {
         if (origin?.kind === SymbolOriginInfoKind.ThisType) {
             return CompletionSource.ThisProperty;
         }
+        if (origin?.kind === SymbolOriginInfoKind.TypeOnlyAlias) {
+            return CompletionSource.TypeOnlyAlias;
+        }
     }
 
     export function getCompletionEntriesFromSymbols(
@@ -1245,7 +1263,7 @@ namespace ts.Completions {
             }
 
             /** True for locals; false for globals, module exports from other files, `this.` completions. */
-            const shouldShadowLaterSymbols = !origin && !(symbol.parent === undefined && !some(symbol.declarations, d => d.getSourceFile() === location.getSourceFile()));
+            const shouldShadowLaterSymbols = (!origin || originIsTypeOnlyAlias(origin)) && !(symbol.parent === undefined && !some(symbol.declarations, d => d.getSourceFile() === location.getSourceFile()));
             uniques.set(name, shouldShadowLaterSymbols);
             insertSorted(entries, entry, compareCompletionEntries, /*allowDuplicates*/ true);
         }
@@ -1261,6 +1279,7 @@ namespace ts.Completions {
         };
 
         function shouldIncludeSymbol(symbol: Symbol, symbolToSortTextIdMap: SymbolSortTextIdMap): boolean {
+            let allFlags = symbol.flags;
             if (!isSourceFile(location)) {
                 // export = /**/ here we want to get all meanings, so any symbol is ok
                 if (isExportAssignment(location.parent)) {
@@ -1287,12 +1306,12 @@ namespace ts.Completions {
                         || symbolToSortTextIdMap[getSymbolId(symbolOrigin)] === SortTextId.LocationPriority)) {
                     return false;
                 }
-                // Continue with origin symbol
-                symbol = symbolOrigin;
+
+                allFlags |= getCombinedLocalAndExportSymbolFlags(symbolOrigin);
 
                 // import m = /**/ <-- It can only access namespace (if typing import = x. this would get member symbols and not namespace)
                 if (isInRightSideOfInternalImportEqualsDeclaration(location)) {
-                    return !!(symbol.flags & SymbolFlags.Namespace);
+                    return !!(allFlags & SymbolFlags.Namespace);
                 }
 
                 if (isTypeOnlyLocation) {
@@ -1302,7 +1321,7 @@ namespace ts.Completions {
             }
 
             // expressions are value space (which includes the value namespaces)
-            return !!(getCombinedLocalAndExportSymbolFlags(symbol) & SymbolFlags.Value);
+            return !!(allFlags & SymbolFlags.Value);
         }
     }
 
@@ -1533,6 +1552,19 @@ namespace ts.Completions {
             }
         }
 
+        if (originIsTypeOnlyAlias(origin)) {
+            const codeAction = codefix.getPromoteTypeOnlyCompletionAction(
+                sourceFile,
+                origin.declaration.name,
+                program,
+                host,
+                formatContext,
+                preferences);
+
+            Debug.assertIsDefined(codeAction, "Expected to have a code action for promoting type-only alias");
+            return { codeActions: [codeAction], sourceDisplay: undefined };
+        }
+
         if (!origin || !(originIsExport(origin) || originIsResolvedExport(origin))) {
             return { codeActions: undefined, sourceDisplay: undefined };
         }
@@ -2314,14 +2346,23 @@ namespace ts.Completions {
             isInSnippetScope = isSnippetScope(scopeNode);
 
             const symbolMeanings = (isTypeOnlyLocation ? SymbolFlags.None : SymbolFlags.Value) | SymbolFlags.Type | SymbolFlags.Namespace | SymbolFlags.Alias;
+            const typeOnlyAliasNeedsPromotion = previousToken && !isValidTypeOnlyAliasUseSite(previousToken);
 
             symbols = concatenate(symbols, typeChecker.getSymbolsInScope(scopeNode, symbolMeanings));
             Debug.assertEachIsDefined(symbols, "getSymbolsInScope() should all be defined");
-            for (const symbol of symbols) {
+            for (let i = 0; i < symbols.length; i++) {
+                const symbol = symbols[i];
                 if (!typeChecker.isArgumentsSymbol(symbol) &&
                     !some(symbol.declarations, d => d.getSourceFile() === sourceFile)) {
                     symbolToSortTextIdMap[getSymbolId(symbol)] = SortTextId.GlobalsOrKeywords;
                 }
+                if (typeOnlyAliasNeedsPromotion && !(symbol.flags & SymbolFlags.Value)) {
+                    const typeOnlyAliasDeclaration = symbol.declarations && find(symbol.declarations, isTypeOnlyImportOrExportDeclaration);
+                    if (typeOnlyAliasDeclaration) {
+                        const origin: SymbolOriginInfoTypeOnlyAlias = { kind: SymbolOriginInfoKind.TypeOnlyAlias, declaration: typeOnlyAliasDeclaration };
+                        symbolToOriginInfoMap[i] = origin;
+                    }
+                }
             }
 
             // Need to insert 'this.' before properties of `this` type, so only do that if `includeInsertTextCompletions`
@@ -3901,10 +3942,15 @@ namespace ts.Completions {
 
     /** True if symbol is a type or a module containing at least one type. */
     function symbolCanBeReferencedAtTypeLocation(symbol: Symbol, checker: TypeChecker, seenModules = new Map<SymbolId, true>()): boolean {
-        const sym = skipAlias(symbol.exportSymbol || symbol, checker);
-        return !!(sym.flags & SymbolFlags.Type) || checker.isUnknownSymbol(sym) ||
-            !!(sym.flags & SymbolFlags.Module) && addToSeen(seenModules, getSymbolId(sym)) &&
-                checker.getExportsOfModule(sym).some(e => symbolCanBeReferencedAtTypeLocation(e, checker, seenModules));
+        // Since an alias can be merged with a local declaration, we need to test both the alias and its target.
+        // This code used to just test the result of `skipAlias`, but that would ignore any locally introduced meanings.
+        return nonAliasCanBeReferencedAtTypeLocation(symbol) || nonAliasCanBeReferencedAtTypeLocation(skipAlias(symbol.exportSymbol || symbol, checker));
+
+        function nonAliasCanBeReferencedAtTypeLocation(symbol: Symbol): boolean {
+            return !!(symbol.flags & SymbolFlags.Type) || checker.isUnknownSymbol(symbol) ||
+                !!(symbol.flags & SymbolFlags.Module) && addToSeen(seenModules, getSymbolId(symbol)) &&
+                checker.getExportsOfModule(symbol).some(e => symbolCanBeReferencedAtTypeLocation(e, checker, seenModules));
+        }
     }
 
     function isDeprecated(symbol: Symbol, checker: TypeChecker) {

src/services/textChanges.ts

@@ -339,6 +339,7 @@ namespace ts.textChanges {
             this.deletedNodes.push({ sourceFile, node });
         }
 
+        /** Stop! Consider using `delete` instead, which has logic for deleting nodes from delimited lists. */
         public deleteNode(sourceFile: SourceFile, node: Node, options: ConfigurableStartEnd = { leadingTriviaOption: LeadingTriviaOption.IncludeAll }): void {
             this.deleteRange(sourceFile, getAdjustedRange(sourceFile, node, node, options));
         }
@@ -786,6 +787,20 @@ namespace ts.textChanges {
             this.insertText(sourceFile, node.getStart(sourceFile), "export ");
         }
 
+        public insertImportSpecifierAtIndex(sourceFile: SourceFile, importSpecifier: ImportSpecifier, namedImports: NamedImports, index: number) {
+            const prevSpecifier = namedImports.elements[index - 1];
+            if (prevSpecifier) {
+                this.insertNodeInListAfter(sourceFile, prevSpecifier, importSpecifier);
+            }
+            else {
+                this.insertNodeBefore(
+                    sourceFile,
+                    namedImports.elements[0],
+                    importSpecifier,
+                    !positionsAreOnSameLine(namedImports.elements[0].getStart(), namedImports.parent.parent.getStart(), sourceFile));
+            }
+        }
+
         /**
          * This function should be used to insert nodes in lists when nodes don't carry separators as the part of the node range,
          * i.e. arguments in arguments lists, parameters in parameter lists etc.

tests/baselines/reference/api/tsserverlibrary.d.ts

@@ -1720,19 +1720,23 @@ declare namespace ts {
         readonly parent: ImportClause & {
             readonly isTypeOnly: true;
         };
-    } | ImportSpecifier & {
+    } | ImportSpecifier & ({
+        readonly isTypeOnly: true;
+    } | {
         readonly parent: NamedImports & {
             readonly parent: ImportClause & {
                 readonly isTypeOnly: true;
             };
         };
-    } | ExportSpecifier & {
+    }) | ExportSpecifier & ({
+        readonly isTypeOnly: true;
+    } | {
         readonly parent: NamedExports & {
             readonly parent: ExportDeclaration & {
                 readonly isTypeOnly: true;
             };
         };
-    };
+    });
     /**
      * This is either an `export =` or an `export default` declaration.
      * Unless `isExportEquals` is set, this node was parsed as an `export default`.

tests/baselines/reference/api/typescript.d.ts

@@ -1720,19 +1720,23 @@ declare namespace ts {
         readonly parent: ImportClause & {
             readonly isTypeOnly: true;
         };
-    } | ImportSpecifier & {
+    } | ImportSpecifier & ({
+        readonly isTypeOnly: true;
+    } | {
         readonly parent: NamedImports & {
             readonly parent: ImportClause & {
                 readonly isTypeOnly: true;
             };
         };
-    } | ExportSpecifier & {
+    }) | ExportSpecifier & ({
+        readonly isTypeOnly: true;
+    } | {
         readonly parent: NamedExports & {
             readonly parent: ExportDeclaration & {
                 readonly isTypeOnly: true;
             };
         };
-    };
+    });
     /**
      * This is either an `export =` or an `export default` declaration.
      * Unless `isExportEquals` is set, this node was parsed as an `export default`.

tests/cases/fourslash/completionsImport_promoteTypeOnly1.ts

@@ -0,0 +1,34 @@
+/// <reference path="fourslash.ts" />
+// @module: es2015
+
+// @Filename: /exports.ts
+//// export interface SomeInterface {}
+//// export class SomePig {}
+
+// @Filename: /a.ts
+//// import type { SomeInterface, SomePig } from "./exports.js";
+//// new SomePig/**/
+
+verify.completions({
+  marker: "",
+  exact: completion.globalsPlus([{
+    name: "SomePig",
+    source: completion.CompletionSource.TypeOnlyAlias,
+    hasAction: true,
+  }]),
+  preferences: { includeCompletionsForModuleExports: true },
+});
+
+verify.applyCodeActionFromCompletion("", {
+  name: "SomePig",
+  source: completion.CompletionSource.TypeOnlyAlias,
+  description: `Remove 'type' from import declaration from "./exports.js"`,
+  newFileContent:
+`import { SomeInterface, SomePig } from "./exports.js";
+new SomePig`,
+  preferences: {
+    includeCompletionsForModuleExports: true,
+    allowIncompleteCompletions: true,
+    includeInsertTextCompletions: true,
+  },
+});

tests/cases/fourslash/completionsImport_promoteTypeOnly2.ts

@@ -0,0 +1,19 @@
+/// <reference path="fourslash.ts" />
+
+// @module: es2015
+
+// @Filename: /exports.ts
+//// export interface SomeInterface {}
+
+// @Filename: /a.ts
+//// import type { SomeInterface } from "./exports.js";
+//// const SomeInterface = {};
+//// SomeI/**/
+
+// Should NOT promote this
+verify.completions({
+  marker: "",
+  includes: [{
+    name: "SomeInterface"
+  }]
+});

tests/cases/fourslash/completionsImport_promoteTypeOnly3.ts

@@ -0,0 +1,33 @@
+/// <reference path="fourslash.ts" />
+// @module: es2015
+
+// @Filename: /exports.ts
+//// export interface SomeInterface {}
+//// export class SomePig {}
+
+// @Filename: /a.ts
+//// import { type SomePig } from "./exports.js";
+//// new SomePig/**/
+
+verify.completions({
+  marker: "",
+  includes: [{
+    name: "SomePig",
+    source: completion.CompletionSource.TypeOnlyAlias,
+    hasAction: true,
+  }]
+});
+
+verify.applyCodeActionFromCompletion("", {
+  name: "SomePig",
+  source: completion.CompletionSource.TypeOnlyAlias,
+  description: `Remove 'type' from import of 'SomePig' from "./exports.js"`,
+  newFileContent:
+`import { SomePig } from "./exports.js";
+new SomePig`,
+  preferences: {
+    includeCompletionsForModuleExports: true,
+    allowIncompleteCompletions: true,
+    includeInsertTextCompletions: true,
+  },
+});