Obtain target type before calling getBaseTypes (#1409)

Author: ahejlsberg

internal/checker/checker.go

@@ -8349,7 +8349,7 @@ func (c *Checker) isConstructorAccessible(node *ast.Node, signature *Signature)
 }
 
 func (c *Checker) typeHasProtectedAccessibleBase(target *ast.Symbol, t *Type) bool {
-	baseTypes := c.getBaseTypes(t)
+	baseTypes := c.getBaseTypes(c.getTargetType(t))
 	if len(baseTypes) == 0 {
 		return false
 	}

testdata/baselines/reference/compiler/protectedAccessibilityCheck.symbols

@@ -0,0 +1,26 @@
+//// [tests/cases/compiler/protectedAccessibilityCheck.ts] ////
+
+=== protectedAccessibilityCheck.ts ===
+class C {
+>C : Symbol(C, Decl(protectedAccessibilityCheck.ts, 0, 0))
+
+  protected constructor() {}
+}
+
+class B<T = any> extends C {}
+>B : Symbol(B, Decl(protectedAccessibilityCheck.ts, 2, 1))
+>T : Symbol(T, Decl(protectedAccessibilityCheck.ts, 4, 8))
+>C : Symbol(C, Decl(protectedAccessibilityCheck.ts, 0, 0))
+
+class A extends B {
+>A : Symbol(A, Decl(protectedAccessibilityCheck.ts, 4, 29))
+>B : Symbol(B, Decl(protectedAccessibilityCheck.ts, 2, 1))
+
+  f() {
+>f : Symbol(f, Decl(protectedAccessibilityCheck.ts, 6, 19))
+
+    new A();
+>A : Symbol(A, Decl(protectedAccessibilityCheck.ts, 4, 29))
+  }
+}
+

testdata/baselines/reference/compiler/protectedAccessibilityCheck.types

@@ -0,0 +1,26 @@
+//// [tests/cases/compiler/protectedAccessibilityCheck.ts] ////
+
+=== protectedAccessibilityCheck.ts ===
+class C {
+>C : C
+
+  protected constructor() {}
+}
+
+class B<T = any> extends C {}
+>B : B<T>
+>C : C
+
+class A extends B {
+>A : A
+>B : B<any>
+
+  f() {
+>f : () => void
+
+    new A();
+>new A() : A
+>A : typeof A
+  }
+}
+

testdata/tests/cases/compiler/protectedAccessibilityCheck.ts

@@ -0,0 +1,14 @@
+// @strict: true
+// @noEmit: true
+
+class C {
+  protected constructor() {}
+}
+
+class B<T = any> extends C {}
+
+class A extends B {
+  f() {
+    new A();
+  }
+}