Fix alias cannot be used to pass indeterminate entities (#3377)

fix #3376
microsoft · May 16, 2024 · 8424b2e · 8424b2e
1 parent aa91dcd
commit 8424b2e
Show file tree

Hide file tree

Showing 3 changed files with 52 additions and 12 deletions.
diff --git a/.chronus/changes/fix-alias-indeterminate-entity-2024-4-16-19-9-9.md b/.chronus/changes/fix-alias-indeterminate-entity-2024-4-16-19-9-9.md
@@ -0,0 +1,7 @@
+---
+# Change versionKind to one of: internal, fix, dependencies, feature, deprecation, breaking
+changeKind: internal
+packages:
+  - "@typespec/compiler"
+---
+Fixing change from this release 
diff --git a/packages/compiler/src/core/checker.ts b/packages/compiler/src/core/checker.ts
@@ -693,6 +693,13 @@ export function createChecker(program: Program): Checker {
     }
   }
 
+  function getTypeForTypeOrIndeterminate(entity: Type | IndeterminateEntity): Type {
+    if (entity.entityKind === "Indeterminate") {
+      return entity.type;
+    }
+    return entity;
+  }
+
   function getTypeForNode(node: Node, mapper?: TypeMapper): Type {
     const entity = checkNode(node, mapper);
     if (entity === null) {
@@ -1634,7 +1641,7 @@ export function createChecker(program: Program): Checker {
 
     const argumentNodes = node.kind === SyntaxKind.TypeReference ? node.arguments : [];
     const symbolLinks = getSymbolLinks(sym);
-    let baseType: Type;
+    let baseType: Type | IndeterminateEntity;
     if (
       sym.flags &
       (SymbolFlags.Model |
@@ -1664,7 +1671,7 @@ export function createChecker(program: Program): Checker {
         } else if (sym.flags & SymbolFlags.Member) {
           baseType = checkMemberSym(sym, mapper);
         } else {
-          baseType = checkDeclaredType(sym, decl, mapper);
+          baseType = checkDeclaredTypeOrIndeterminate(sym, decl, mapper);
         }
       } else {
         const declaredType = getOrCheckDeclaredType(sym, decl, mapper);
@@ -1726,16 +1733,15 @@ export function createChecker(program: Program): Checker {
     // don't raise deprecation when the usage site is also a deprecated
     // declaration.
     const declarationNode = sym?.declarations[0];
-    if (declarationNode && mapper === undefined) {
+    if (declarationNode && mapper === undefined && isType(baseType)) {
       if (!isTypeReferenceContextDeprecated(node.parent!)) {
         checkDeprecated(baseType, declarationNode, node);
       }
     }
 
     // Elements that could be used as type or values depending on the context
     if (
-      baseType.kind === "EnumMember" ||
-      baseType.kind === "UnionVariant" ||
+      (isType(baseType) && (baseType.kind === "EnumMember" || baseType.kind === "UnionVariant")) ||
       isNullType(baseType)
     ) {
       return createIndeterminateEntity(baseType);
@@ -1780,11 +1786,11 @@ export function createChecker(program: Program): Checker {
    * @param mapper Type mapper for template resolution
    * @returns The declared type for the given node.
    */
-  function checkDeclaredType(
+  function checkDeclaredTypeOrIndeterminate(
     sym: Sym,
     node: TemplateableNode,
     mapper: TypeMapper | undefined
-  ): Type {
+  ): Type | IndeterminateEntity {
     const type =
       sym.flags & SymbolFlags.Model
         ? checkModelStatement(node as ModelStatementNode, mapper)
@@ -1801,6 +1807,14 @@ export function createChecker(program: Program): Checker {
     return type;
   }
 
+  function checkDeclaredType(
+    sym: Sym,
+    node: TemplateableNode,
+    mapper: TypeMapper | undefined
+  ): Type {
+    return getTypeForTypeOrIndeterminate(checkDeclaredTypeOrIndeterminate(sym, node, mapper));
+  }
+
   function getOrInstantiateTemplate(
     templateNode: TemplateableNode,
     params: TemplateParameter[],
@@ -5430,7 +5444,10 @@ export function createChecker(program: Program): Checker {
     return finishType(member);
   }
 
-  function checkAlias(node: AliasStatementNode, mapper: TypeMapper | undefined): Type {
+  function checkAlias(
+    node: AliasStatementNode,
+    mapper: TypeMapper | undefined
+  ): Type | IndeterminateEntity {
     const links = getSymbolLinks(node.symbol);
 
     if (links.declaredType && mapper === undefined) {
@@ -5454,10 +5471,17 @@ export function createChecker(program: Program): Checker {
     }
 
     pendingResolutions.start(aliasSymId, ResolutionKind.Type);
-    const type = getTypeForNode(node.value, mapper);
-    if (!isValue(type)) {
-      linkType(links, type, mapper);
+    const type = checkNode(node.value, mapper);
+    if (type === null) {
+      links.declaredType = errorType;
+      return errorType;
+    }
+    if (isValue(type)) {
+      reportCheckerDiagnostic(createDiagnostic({ code: "value-in-type", target: node.value }));
+      links.declaredType = errorType;
+      return errorType;
     }
+    linkType(links, type as any, mapper);
     pendingResolutions.finish(aliasSymId, ResolutionKind.Type);
 
     return type;

diff --git a/packages/compiler/test/checker/relation.test.ts b/packages/compiler/test/checker/relation.test.ts
@@ -1290,7 +1290,16 @@ describe("compiler: checker: type relations", () => {
   describe("Value constraint", () => {
     describe("valueof string", () => {
       it("can assign string literal", async () => {
-        await checkValueAssignableToConstraint({ source: `"foo bar"`, target: "string" });
+        await checkValueAssignableToConstraint({ source: `"foo bar"`, target: "valueof string" });
+      });
+
+      it("can assign string literal via alias", async () => {
+        const diagnostics = await runner.diagnose(`
+          model Foo<T extends valueof string> {}
+          alias Test = Foo<A>;
+          alias A = "abc";
+          `);
+        expectDiagnosticEmpty(diagnostics);
       });
 
       it("cannot assign numeric literal", async () => {