Don’t issue used-before-initialization errors in declaration files (microsoft#32579)

Author: andrewbranch

src/compiler/checker.ts

@@ -20700,7 +20700,7 @@ namespace ts {
 
         function checkPropertyNotUsedBeforeDeclaration(prop: Symbol, node: PropertyAccessExpression | QualifiedName, right: Identifier): void {
             const { valueDeclaration } = prop;
-            if (!valueDeclaration) {
+            if (!valueDeclaration || getSourceFileOfNode(node).isDeclarationFile) {
                 return;
             }
 

tests/baselines/reference/useBeforeDefinitionInDeclarationFiles.symbols

@@ -0,0 +1,26 @@
+=== tests/cases/compiler/declaration.d.ts ===
+export declare class ClassWithSymbols {
+>ClassWithSymbols : Symbol(ClassWithSymbols, Decl(declaration.d.ts, 0, 0))
+
+  public readonly [Namespace.locallyExportedCustomSymbol]: string;
+>[Namespace.locallyExportedCustomSymbol] : Symbol(ClassWithSymbols[Namespace.locallyExportedCustomSymbol], Decl(declaration.d.ts, 0, 39))
+>Namespace.locallyExportedCustomSymbol : Symbol(Namespace.locallyExportedCustomSymbol, Decl(declaration.d.ts, 5, 14))
+>Namespace : Symbol(Namespace, Decl(declaration.d.ts, 3, 1))
+>locallyExportedCustomSymbol : Symbol(Namespace.locallyExportedCustomSymbol, Decl(declaration.d.ts, 5, 14))
+
+  public [Namespace.fullyExportedCustomSymbol](): void;
+>[Namespace.fullyExportedCustomSymbol] : Symbol(ClassWithSymbols[Namespace.fullyExportedCustomSymbol], Decl(declaration.d.ts, 1, 66))
+>Namespace.fullyExportedCustomSymbol : Symbol(Namespace.fullyExportedCustomSymbol, Decl(declaration.d.ts, 6, 14))
+>Namespace : Symbol(Namespace, Decl(declaration.d.ts, 3, 1))
+>fullyExportedCustomSymbol : Symbol(Namespace.fullyExportedCustomSymbol, Decl(declaration.d.ts, 6, 14))
+}
+export namespace Namespace {
+>Namespace : Symbol(Namespace, Decl(declaration.d.ts, 3, 1))
+
+  export const locallyExportedCustomSymbol: unique symbol;
+>locallyExportedCustomSymbol : Symbol(locallyExportedCustomSymbol, Decl(declaration.d.ts, 5, 14))
+
+  export const fullyExportedCustomSymbol: unique symbol;
+>fullyExportedCustomSymbol : Symbol(fullyExportedCustomSymbol, Decl(declaration.d.ts, 6, 14))
+}
+

tests/baselines/reference/useBeforeDefinitionInDeclarationFiles.types

@@ -0,0 +1,26 @@
+=== tests/cases/compiler/declaration.d.ts ===
+export declare class ClassWithSymbols {
+>ClassWithSymbols : ClassWithSymbols
+
+  public readonly [Namespace.locallyExportedCustomSymbol]: string;
+>[Namespace.locallyExportedCustomSymbol] : string
+>Namespace.locallyExportedCustomSymbol : unique symbol
+>Namespace : typeof Namespace
+>locallyExportedCustomSymbol : unique symbol
+
+  public [Namespace.fullyExportedCustomSymbol](): void;
+>[Namespace.fullyExportedCustomSymbol] : () => void
+>Namespace.fullyExportedCustomSymbol : unique symbol
+>Namespace : typeof Namespace
+>fullyExportedCustomSymbol : unique symbol
+}
+export namespace Namespace {
+>Namespace : typeof Namespace
+
+  export const locallyExportedCustomSymbol: unique symbol;
+>locallyExportedCustomSymbol : unique symbol
+
+  export const fullyExportedCustomSymbol: unique symbol;
+>fullyExportedCustomSymbol : unique symbol
+}
+

tests/cases/compiler/useBeforeDefinitionInDeclarationFiles.ts

@@ -0,0 +1,10 @@
+// @filename: declaration.d.ts
+
+export declare class ClassWithSymbols {
+  public readonly [Namespace.locallyExportedCustomSymbol]: string;
+  public [Namespace.fullyExportedCustomSymbol](): void;
+}
+export namespace Namespace {
+  export const locallyExportedCustomSymbol: unique symbol;
+  export const fullyExportedCustomSymbol: unique symbol;
+}