fix false positive 'variable is used before being assigned' in destructuring (microsoft#29636)

Fixes: microsoft#29458

Author: ajafff

src/compiler/checker.ts

@@ -17089,7 +17089,7 @@ namespace ts {
             // We only look for uninitialized variables in strict null checking mode, and only when we can analyze
             // the entire control flow graph from the variable's declaration (i.e. when the flow container and
             // declaration container are the same).
-            const assumeInitialized = isParameter || isAlias || isOuterVariable || isSpreadDestructuringAssignmentTarget || isModuleExports ||
+            const assumeInitialized = isParameter || isAlias || isOuterVariable || isSpreadDestructuringAssignmentTarget || isModuleExports || isBindingElement(declaration) ||
                 type !== autoType && type !== autoArrayType && (!strictNullChecks || (type.flags & TypeFlags.AnyOrUnknown) !== 0 ||
                 isInTypeQuery(node) || node.parent.kind === SyntaxKind.ExportSpecifier) ||
                 node.parent.kind === SyntaxKind.NonNullExpression ||

tests/baselines/reference/useBeforeDeclaration_destructuring.errors.txt

@@ -0,0 +1,13 @@
+tests/cases/compiler/useBeforeDeclaration_destructuring.ts(1,1): error TS2448: Block-scoped variable 'a' used before its declaration.
+
+
+==== tests/cases/compiler/useBeforeDeclaration_destructuring.ts (1 errors) ====
+    a;
+    ~
+!!! error TS2448: Block-scoped variable 'a' used before its declaration.
+!!! related TS2728 tests/cases/compiler/useBeforeDeclaration_destructuring.ts:2:6: 'a' is declared here.
+    let {a, b = a} = {a: '', b: 1};
+    b;
+    
+    function test({c, d = c}: Record<string, number>) {}
+    

tests/baselines/reference/useBeforeDeclaration_destructuring.js

@@ -0,0 +1,15 @@
+//// [useBeforeDeclaration_destructuring.ts]
+a;
+let {a, b = a} = {a: '', b: 1};
+b;
+
+function test({c, d = c}: Record<string, number>) {}
+
+
+//// [useBeforeDeclaration_destructuring.js]
+a;
+var _a = { a: '', b: 1 }, a = _a.a, _b = _a.b, b = _b === void 0 ? a : _b;
+b;
+function test(_a) {
+    var c = _a.c, _b = _a.d, d = _b === void 0 ? c : _b;
+}

tests/baselines/reference/useBeforeDeclaration_destructuring.symbols

@@ -0,0 +1,21 @@
+=== tests/cases/compiler/useBeforeDeclaration_destructuring.ts ===
+a;
+>a : Symbol(a, Decl(useBeforeDeclaration_destructuring.ts, 1, 5))
+
+let {a, b = a} = {a: '', b: 1};
+>a : Symbol(a, Decl(useBeforeDeclaration_destructuring.ts, 1, 5))
+>b : Symbol(b, Decl(useBeforeDeclaration_destructuring.ts, 1, 7))
+>a : Symbol(a, Decl(useBeforeDeclaration_destructuring.ts, 1, 5))
+>a : Symbol(a, Decl(useBeforeDeclaration_destructuring.ts, 1, 18))
+>b : Symbol(b, Decl(useBeforeDeclaration_destructuring.ts, 1, 24))
+
+b;
+>b : Symbol(b, Decl(useBeforeDeclaration_destructuring.ts, 1, 7))
+
+function test({c, d = c}: Record<string, number>) {}
+>test : Symbol(test, Decl(useBeforeDeclaration_destructuring.ts, 2, 2))
+>c : Symbol(c, Decl(useBeforeDeclaration_destructuring.ts, 4, 15))
+>d : Symbol(d, Decl(useBeforeDeclaration_destructuring.ts, 4, 17))
+>c : Symbol(c, Decl(useBeforeDeclaration_destructuring.ts, 4, 15))
+>Record : Symbol(Record, Decl(lib.es5.d.ts, --, --))
+

tests/baselines/reference/useBeforeDeclaration_destructuring.types

@@ -0,0 +1,23 @@
+=== tests/cases/compiler/useBeforeDeclaration_destructuring.ts ===
+a;
+>a : any
+
+let {a, b = a} = {a: '', b: 1};
+>a : any
+>b : any
+>a : any
+>{a: '', b: 1} : { a: string; b?: number; }
+>a : string
+>'' : ""
+>b : number
+>1 : 1
+
+b;
+>b : any
+
+function test({c, d = c}: Record<string, number>) {}
+>test : ({ c, d }: Record<string, number>) => void
+>c : number
+>d : number
+>c : number
+

tests/cases/compiler/useBeforeDeclaration_destructuring.ts

@@ -0,0 +1,5 @@
+a;
+let {a, b = a} = {a: '', b: 1};
+b;
+
+function test({c, d = c}: Record<string, number>) {}