feat(language-service): implement autocompletion for global properties (Ivy) (#39250)

This commit adds support in the Ivy Language Service for autocompletion in a
global context - e.g. a {{foo|}} completion.

Support is added both for the primary function `getCompletionsAtPosition` as
well as the detail functions `getCompletionEntryDetails` and
`getCompletionEntrySymbol`. These latter operations are not used yet as an
upstream change to the extension is required to advertise and support this
capability.

PR Close #39250

packages/compiler-cli/src/ngtsc/typecheck/api/checker.ts

@@ -50,7 +50,7 @@ export interface TemplateTypeChecker {
    * is not valid. If the template cannot be parsed correctly, no override will occur.
    */
   overrideComponentTemplate(component: ts.ClassDeclaration, template: string):
-      {nodes: TmplAstNode[], errors?: ParseError[]};
+      {nodes: TmplAstNode[], errors: ParseError[]|null};
 
   /**
    * Get all `ts.Diagnostic`s currently available for the given `ts.SourceFile`.

packages/compiler-cli/src/ngtsc/typecheck/api/symbols.ts

@@ -32,6 +32,11 @@ export enum SymbolKind {
 export type Symbol = InputBindingSymbol|OutputBindingSymbol|ElementSymbol|ReferenceSymbol|
     VariableSymbol|ExpressionSymbol|DirectiveSymbol|TemplateSymbol|DomBindingSymbol;
 
+/**
+ * A `Symbol` which declares a new named entity in the template scope.
+ */
+export type TemplateDeclarationSymbol = ReferenceSymbol|VariableSymbol;
+
 /** Information about where a `ts.Node` can be found in the type check block shim file. */
 export interface ShimLocation {
   /**

packages/compiler-cli/src/ngtsc/typecheck/src/checker.ts

@@ -138,16 +138,12 @@ export class TemplateTypeCheckerImpl implements TemplateTypeChecker {
   }
 
   overrideComponentTemplate(component: ts.ClassDeclaration, template: string):
-      {nodes: TmplAstNode[], errors?: ParseError[]} {
+      {nodes: TmplAstNode[], errors: ParseError[]|null} {
     const {nodes, errors} = parseTemplate(template, 'override.html', {
       preserveWhitespaces: true,
       leadingTriviaChars: [],
     });
 
-    if (errors !== null) {
-      return {nodes, errors};
-    }
-
     const filePath = absoluteFromSourceFile(component.getSourceFile());
 
     const fileRecord = this.getFileData(filePath);
@@ -169,7 +165,7 @@ export class TemplateTypeCheckerImpl implements TemplateTypeChecker {
     this.completionCache.delete(component);
     this.symbolBuilderCache.delete(component);
 
-    return {nodes};
+    return {nodes, errors};
   }
 
   isTrackedTypeCheckFile(filePath: AbsoluteFsPath): boolean {