[cfe] Allow non-const constructor invocations in const functions.

Change-Id: Ieb8d3030c6132ccf9037e64cef3ba6c4eeaa90ea
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/197180
Reviewed-by: Jake Macdonald <jakemac@google.com>
Reviewed-by: Dmitry Stefantsov <dmitryas@google.com>
Commit-Queue: Kallen Tu <kallentu@google.com>

pkg/front_end/lib/src/fasta/kernel/constant_evaluator.dart

@@ -1444,7 +1444,7 @@ class ConstantEvaluator implements ExpressionVisitor<Constant> {
 
   @override
   Constant visitConstructorInvocation(ConstructorInvocation node) {
-    if (!node.isConst) {
+    if (!node.isConst && !enableConstFunctions) {
       return createInvalidExpressionConstant(
           node, 'Non-constant constructor invocation "$node".');
     }

pkg/front_end/testcases/const_functions/const_functions_const_ctor.dart

@@ -23,6 +23,9 @@ class A {
   }
 }
 
+const var3 = fn();
+A fn() => A();
+
 void main() {
   Expect.equals(var1.name, printString);
 }

pkg/front_end/testcases/const_functions/const_functions_const_ctor.dart.strong.expect

@@ -21,6 +21,9 @@ class A extends core::Object /*hasConstConstructor*/  {
 static const field core::String printString = #C1;
 static const field self::Simple var1 = #C2;
 static const field self::A var2 = #C3;
+static const field self::A var3 = #C3;
+static method fn() → self::A
+  return new self::A::•();
 static method main() → void {
   exp::Expect::equals((#C2).{self::Simple::name}, #C1);
 }

pkg/front_end/testcases/const_functions/const_functions_const_ctor.dart.strong.transformed.expect

@@ -21,6 +21,9 @@ class A extends core::Object /*hasConstConstructor*/  {
 static const field core::String printString = #C1;
 static const field self::Simple var1 = #C2;
 static const field self::A var2 = #C3;
+static const field self::A var3 = #C3;
+static method fn() → self::A
+  return new self::A::•();
 static method main() → void {
   exp::Expect::equals((#C2).{self::Simple::name}, #C1);
 }

pkg/front_end/testcases/const_functions/const_functions_const_ctor.dart.textual_outline.expect

@@ -9,4 +9,6 @@ const var2 = A();
 class A {
   const A() {}
 }
+const var3 = fn();
+A fn() => A();
 void main() {}

pkg/front_end/testcases/const_functions/const_functions_const_ctor.dart.weak.expect

@@ -21,6 +21,9 @@ class A extends core::Object /*hasConstConstructor*/  {
 static const field core::String printString = #C1;
 static const field self::Simple var1 = #C2;
 static const field self::A var2 = #C3;
+static const field self::A var3 = #C3;
+static method fn() → self::A
+  return new self::A::•();
 static method main() → void {
   exp::Expect::equals((#C2).{self::Simple::name}, #C1);
 }

pkg/front_end/testcases/const_functions/const_functions_const_ctor.dart.weak.outline.expect

@@ -18,6 +18,9 @@ class A extends core::Object /*hasConstConstructor*/  {
 static const field core::String printString = "print";
 static const field self::Simple var1 = const self::Simple::•(self::printString);
 static const field self::A var2 = const self::A::•();
+static const field self::A var3 = self::fn();
+static method fn() → self::A
+  ;
 static method main() → void
   ;
 
@@ -25,4 +28,4 @@ static method main() → void
 Extra constant evaluation status:
 Evaluated: ConstructorInvocation @ org-dartlang-testcase:///const_functions_const_ctor.dart:10:14 -> InstanceConstant(const Simple{Simple.name: "print"})
 Evaluated: ConstructorInvocation @ org-dartlang-testcase:///const_functions_const_ctor.dart:19:14 -> InstanceConstant(const A{})
-Extra constant evaluation: evaluated: 3, effectively constant: 2
+Extra constant evaluation: evaluated: 4, effectively constant: 2

pkg/front_end/testcases/const_functions/const_functions_const_ctor.dart.weak.transformed.expect

@@ -21,6 +21,9 @@ class A extends core::Object /*hasConstConstructor*/  {
 static const field core::String printString = #C1;
 static const field self::Simple var1 = #C2;
 static const field self::A var2 = #C3;
+static const field self::A var3 = #C3;
+static method fn() → self::A
+  return new self::A::•();
 static method main() → void {
   exp::Expect::equals((#C2).{self::Simple::name}, #C1);
 }

pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart

@@ -38,4 +38,9 @@ class B extends A {
   const B() : super();
 }
 
+const var4 = C();
+class C {
+  int? x;
+}
+
 void main() {}

pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart.strong.expect

@@ -2,6 +2,11 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
+// pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart:41:14: Error: Cannot invoke a non-'const' constructor where a const expression is expected.
+// Try using a constructor or factory that is 'const'.
+// const var4 = C();
+//              ^
+//
 // pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart:26:5: Error: Constructors can't have a return type.
 // Try removing the return type.
 //     return Simple2(this.name);
@@ -60,6 +65,12 @@ class B extends self::A /*hasConstConstructor*/  {
     : super self::A::•()
     ;
 }
+class C extends core::Object {
+  field core::int? x = null;
+  synthetic constructor •() → self::C
+    : super core::Object::•()
+    ;
+}
 static const field core::String printString = #C1;
 static const field self::Simple var1 = invalid-expression "This assertion failed.";
 static const field self::Simple2 var2 = invalid-expression "pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart:26:5: Error: Constructors can't have a return type.
@@ -67,6 +78,10 @@ Try removing the return type.
     return Simple2(this.name);
     ^";
 static const field self::B var3 = invalid-expression "This assertion failed.";
+static const field dynamic var4 = invalid-expression "pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart:41:14: Error: Cannot invoke a non-'const' constructor where a const expression is expected.
+Try using a constructor or factory that is 'const'.
+const var4 = C();
+             ^";
 static method main() → void {}
 
 constants  {

pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart.strong.transformed.expect

@@ -2,6 +2,11 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
+// pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart:41:14: Error: Cannot invoke a non-'const' constructor where a const expression is expected.
+// Try using a constructor or factory that is 'const'.
+// const var4 = C();
+//              ^
+//
 // pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart:26:5: Error: Constructors can't have a return type.
 // Try removing the return type.
 //     return Simple2(this.name);
@@ -60,6 +65,12 @@ class B extends self::A /*hasConstConstructor*/  {
     : super self::A::•()
     ;
 }
+class C extends core::Object {
+  field core::int? x = null;
+  synthetic constructor •() → self::C
+    : super core::Object::•()
+    ;
+}
 static const field core::String printString = #C1;
 static const field self::Simple var1 = invalid-expression "This assertion failed.";
 static const field self::Simple2 var2 = invalid-expression "pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart:26:5: Error: Constructors can't have a return type.
@@ -67,6 +78,10 @@ Try removing the return type.
     return Simple2(this.name);
     ^";
 static const field self::B var3 = invalid-expression "This assertion failed.";
+static const field dynamic var4 = invalid-expression "pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart:41:14: Error: Cannot invoke a non-'const' constructor where a const expression is expected.
+Try using a constructor or factory that is 'const'.
+const var4 = C();
+             ^";
 static method main() → void {}
 
 constants  {

pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart.textual_outline.expect

@@ -17,4 +17,8 @@ class A {
 class B extends A {
   const B() : super();
 }
+const var4 = C();
+class C {
+  int? x;
+}
 void main() {}

pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart.weak.expect

@@ -2,6 +2,11 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
+// pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart:41:14: Error: Cannot invoke a non-'const' constructor where a const expression is expected.
+// Try using a constructor or factory that is 'const'.
+// const var4 = C();
+//              ^
+//
 // pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart:26:5: Error: Constructors can't have a return type.
 // Try removing the return type.
 //     return Simple2(this.name);
@@ -60,6 +65,12 @@ class B extends self::A /*hasConstConstructor*/  {
     : super self::A::•()
     ;
 }
+class C extends core::Object {
+  field core::int? x = null;
+  synthetic constructor •() → self::C
+    : super core::Object::•()
+    ;
+}
 static const field core::String printString = #C1;
 static const field self::Simple var1 = invalid-expression "This assertion failed.";
 static const field self::Simple2 var2 = invalid-expression "pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart:26:5: Error: Constructors can't have a return type.
@@ -67,6 +78,10 @@ Try removing the return type.
     return Simple2(this.name);
     ^";
 static const field self::B var3 = invalid-expression "This assertion failed.";
+static const field dynamic var4 = invalid-expression "pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart:41:14: Error: Cannot invoke a non-'const' constructor where a const expression is expected.
+Try using a constructor or factory that is 'const'.
+const var4 = C();
+             ^";
 static method main() → void {}
 
 constants  {

pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart.weak.outline.expect

@@ -1,4 +1,12 @@
 library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart:41:14: Error: Cannot invoke a non-'const' constructor where a const expression is expected.
+// Try using a constructor or factory that is 'const'.
+// const var4 = C();
+//              ^
+//
 import self as self;
 import "dart:core" as core;
 
@@ -26,10 +34,19 @@ class B extends self::A /*hasConstConstructor*/  {
     : super self::A::•()
     ;
 }
+class C extends core::Object {
+  field core::int? x;
+  synthetic constructor •() → self::C
+    ;
+}
 static const field core::String printString = "print";
 static const field self::Simple var1 = const self::Simple::•(self::printString);
 static const field self::Simple2 var2 = const self::Simple2::•(self::printString);
 static const field self::B var3 = const self::B::•();
+static const field dynamic var4 = invalid-expression "pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart:41:14: Error: Cannot invoke a non-'const' constructor where a const expression is expected.
+Try using a constructor or factory that is 'const'.
+const var4 = C();
+             ^";
 static method main() → void
   ;
 

pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart.weak.transformed.expect

@@ -2,6 +2,11 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
+// pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart:41:14: Error: Cannot invoke a non-'const' constructor where a const expression is expected.
+// Try using a constructor or factory that is 'const'.
+// const var4 = C();
+//              ^
+//
 // pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart:26:5: Error: Constructors can't have a return type.
 // Try removing the return type.
 //     return Simple2(this.name);
@@ -60,6 +65,12 @@ class B extends self::A /*hasConstConstructor*/  {
     : super self::A::•()
     ;
 }
+class C extends core::Object {
+  field core::int? x = null;
+  synthetic constructor •() → self::C
+    : super core::Object::•()
+    ;
+}
 static const field core::String printString = #C1;
 static const field self::Simple var1 = invalid-expression "This assertion failed.";
 static const field self::Simple2 var2 = invalid-expression "pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart:26:5: Error: Constructors can't have a return type.
@@ -67,6 +78,10 @@ Try removing the return type.
     return Simple2(this.name);
     ^";
 static const field self::B var3 = invalid-expression "This assertion failed.";
+static const field dynamic var4 = invalid-expression "pkg/front_end/testcases/const_functions/const_functions_const_ctor_error.dart:41:14: Error: Cannot invoke a non-'const' constructor where a const expression is expected.
+Try using a constructor or factory that is 'const'.
+const var4 = C();
+             ^";
 static method main() → void {}
 
 constants  {

tests/language/const_functions/const_functions_const_ctor_error_test.dart

@@ -53,3 +53,13 @@ class A {
 class B extends A {
   const B() : super();
 }
+
+const var4 = C();
+//           ^^^
+// [analyzer] COMPILE_TIME_ERROR.CONST_WITH_NON_CONST
+//           ^^^^^
+// [analyzer] COMPILE_TIME_ERROR.CONST_INITIALIZED_WITH_NON_CONSTANT_VALUE
+// [cfe] Cannot invoke a non-'const' constructor where a const expression is expected.
+class C {
+  int? x;
+}

tests/language/const_functions/const_functions_const_ctor_test.dart

@@ -29,6 +29,11 @@ class A {
   }
 }
 
+const var3 = fn();
+//           ^^^^
+// [analyzer] COMPILE_TIME_ERROR.CONST_INITIALIZED_WITH_NON_CONSTANT_VALUE
+A fn() => A();
+
 void main() {
   Expect.equals(var1.name, printString);
 }