The truthiness of an any holding an object is true

tslang/lib/TypeScript/MLIRGenCast.cpp

@@ -2161,7 +2161,18 @@ namespace mlirgen
             }
         }
 
-        ss << "\nthrow \"Can't cast from any type\";\n";                    
+        // Every falsy value - 0, NaN, "", false, null, undefined, 0n - is a primitive answered above.
+        // What is left - a class instance, an object, an array, a function - is truthy, as in
+        // JavaScript: `if (a)` of an `any` holding one threw instead.
+        if (mlir::isa<mlir_ts::BooleanType>(type) || mlir::isa<mlir_ts::TypePredicateType>(type))
+        {
+            ss << "\nreturn true;\n";
+        }
+        else
+        {
+            ss << "\nthrow \"Can't cast from any type\";\n";
+        }
+
         ss << S("}\n");
 
         auto src = ss.str();

tslang/test/tester/CMakeLists.txt

@@ -631,6 +631,7 @@ tslang_add_test(NAME test-compile-00-interface-instanceof COMMAND test-runner "$
 tslang_add_test(NAME test-compile-01-any COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/01any.ts")
 tslang_add_test(NAME test-compile-00-any-types COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00any_types.ts")
 tslang_add_test(NAME test-compile-00-any-compare COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00any_compare.ts")
+tslang_add_test(NAME test-compile-00-any-truthiness-objects COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00any_truthiness_objects.ts")
 tslang_add_test(NAME test-compile-00-any-generic-equals COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00any_generic_equals.ts")
 tslang_add_test(NAME test-compile-00-generator COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00generator.ts")
 tslang_add_test(NAME test-compile-00-generator-2 COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00generator2.ts")
@@ -1183,6 +1184,7 @@ tslang_add_test(NAME test-jit-00-interface-instanceof COMMAND test-runner -jit "
 tslang_add_test(NAME test-jit-01-any COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/01any.ts")
 tslang_add_test(NAME test-jit-00-any-types COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00any_types.ts")
 tslang_add_test(NAME test-jit-00-any-compare COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00any_compare.ts")
+tslang_add_test(NAME test-jit-00-any-truthiness-objects COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00any_truthiness_objects.ts")
 tslang_add_test(NAME test-jit-00-any-generic-equals COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00any_generic_equals.ts")
 tslang_add_test(NAME test-jit-00-generator COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00generator.ts")
 tslang_add_test(NAME test-jit-00-generator-2 COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00generator2.ts")
@@ -1785,6 +1787,7 @@ tslang_add_test(NAME test-jit-none-strings COMMAND test-runner -jit -mm=none "${
 
 # every single-file test the default model runs, in either tier
 set(TSLANG_CORPUS
+    00any_truthiness_objects.ts
     00add_promotes_both_operands.ts
     00conditional_owned_result.ts
     00const_array_nested_elements.ts

tslang/test/tester/tests/00any_truthiness_objects.ts

@@ -0,0 +1,30 @@
+// The truthiness of an `any` holding an object - a class instance, an object literal, an array -
+// is true, as in JavaScript. It threw "Can't cast from any type".
+class P {
+    x = 1;
+}
+
+function main() {
+    const c: any = new P();
+    assert(c ? true : false, "class instance");
+    assert(!!c, "!! of a class instance");
+
+    const o: any = { x: 1 };
+    let seen = false;
+    if (o) {
+        seen = true;
+    }
+    assert(seen, "object literal");
+
+    const a: any = [1, 2];
+    assert(a ? true : false, "array");
+
+    const z: any = 0;
+    assert(!z, "0 is still falsy");
+    const e: any = "";
+    assert(!e, "empty string is still falsy");
+    const n: any = null;
+    assert(!n, "null is still falsy");
+
+    print("done.");
+}