pick changes

Author: Jack-Works

src/compiler/checker.ts

@@ -34767,8 +34767,13 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             case SyntaxKind.EqualsEqualsEqualsToken:
             case SyntaxKind.ExclamationEqualsEqualsToken:
                 if (isLiteralExpressionOfObject(left) || isLiteralExpressionOfObject(right)) {
-                    const eqType = operator === SyntaxKind.EqualsEqualsToken || operator === SyntaxKind.EqualsEqualsEqualsToken;
-                    error(errorNode, Diagnostics.This_condition_will_always_return_0_since_JavaScript_compares_objects_by_reference_not_value, eqType ? "false" : "true");
+                    if (isInJSFile(left) && (operator === SyntaxKind.EqualsEqualsToken || operator === SyntaxKind.ExclamationEqualsToken)) {
+                        // we skip the emit for {} == {} in JS files
+                    }
+                    else {
+                        const eqType = operator === SyntaxKind.EqualsEqualsToken || operator === SyntaxKind.EqualsEqualsEqualsToken;
+                        error(errorNode, Diagnostics.This_condition_will_always_return_0_since_JavaScript_compares_objects_by_reference_not_value, eqType ? "false" : "true");
+                    }
                 }
                 checkNaNEquality(errorNode, operator, left, right);
                 reportOperatorErrorUnless((left, right) => isTypeEqualityComparableTo(left, right) || isTypeEqualityComparableTo(right, left));

src/compiler/program.ts

@@ -1059,6 +1059,8 @@ export const plainJSErrors: Set<number> = new Set([
     Diagnostics.Class_constructor_may_not_be_a_generator.code,
     Diagnostics.Class_constructor_may_not_be_an_accessor.code,
     Diagnostics.await_expressions_are_only_allowed_within_async_functions_and_at_the_top_levels_of_modules.code,
+    // Type errors
+    Diagnostics.This_condition_will_always_return_0_since_JavaScript_compares_objects_by_reference_not_value.code,
 ]);
 
 /**

tests/baselines/reference/plainJSTypeErrors.symbols

@@ -1,8 +1,8 @@
 === tests/cases/conformance/salsa/plainJSTypeErrors.js ===
+
 // should error
-No type information for this code.if ({} === {}) {}
-No type information for this code.
-No type information for this code.// should not error
-No type information for this code.if ({} == {}) {}
-No type information for this code.
-No type information for this code.
+if ({} === {}) {}
+
+// should not error
+if ({} == {}) {}
+