[cfe] Uninitialized variable declarations in const functions.

Change-Id: I1c27902a0af7648b4352b0cd21691cf9f88b78fb
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/194460
Commit-Queue: Kallen Tu <kallentu@google.com>
Reviewed-by: Dmitry Stefantsov <dmitryas@google.com>
Reviewed-by: Bob Nystrom <rnystrom@google.com>
Reviewed-by: Jake Macdonald <jakemac@google.com>

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

@@ -3607,8 +3607,11 @@ class StatementConstantEvaluator extends StatementVisitor<ExecutionStatus> {
 
   @override
   ExecutionStatus visitVariableDeclaration(VariableDeclaration node) {
-    Constant value = evaluate(node.initializer);
-    if (value is AbortConstant) return new AbortStatus(value);
+    Constant value;
+    if (node.initializer != null) {
+      value = evaluate(node.initializer);
+      if (value is AbortConstant) return new AbortStatus(value);
+    }
     exprEvaluator.env.addVariableValue(node, value);
     return const ProceedStatus();
   }

pkg/front_end/testcases/const_functions/const_functions_variable_declarations.dart

@@ -39,6 +39,29 @@ int function5() {
   return constant;
 }
 
+const var6 = function6();
+int function6() {
+  var a;
+  a = 2;
+  return a;
+}
+
+const var7 = function7();
+int function7() {
+  var a;
+  var b;
+  a = 2;
+  return a;
+}
+
+const var8 = function8();
+int function8() {
+  var a;
+  int? b;
+  a = 2;
+  return a;
+}
+
 void main() {
   Expect.equals(var1, 4);
   Expect.equals(var1_1, 5);
@@ -46,4 +69,7 @@ void main() {
   Expect.equals(var3, 6);
   Expect.equals(var4, 2);
   Expect.equals(var5, -2);
+  Expect.equals(var6, 2);
+  Expect.equals(var7, 2);
+  Expect.equals(var8, 2);
 }

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

@@ -11,6 +11,9 @@ static const field core::String var2 = #C3;
 static const field core::int var3 = #C4;
 static const field core::int var4 = #C5;
 static const field core::int var5 = #C6;
+static const field core::int var6 = #C5;
+static const field core::int var7 = #C5;
+static const field core::int var8 = #C5;
 static method function1(core::int a, core::int b) → core::int {
   core::int x = 1.{core::num::+}(a).{core::num::+}(b);
   return x;
@@ -32,6 +35,23 @@ static method function4() → core::int {
 static method function5() → core::int {
   return #C6;
 }
+static method function6() → core::int {
+  dynamic a;
+  a = 2;
+  return a as{TypeError,ForDynamic,ForNonNullableByDefault} core::int;
+}
+static method function7() → core::int {
+  dynamic a;
+  dynamic b;
+  a = 2;
+  return a as{TypeError,ForDynamic,ForNonNullableByDefault} core::int;
+}
+static method function8() → core::int {
+  dynamic a;
+  core::int? b;
+  a = 2;
+  return a as{TypeError,ForDynamic,ForNonNullableByDefault} core::int;
+}
 static method main() → void {
   exp::Expect::equals(#C1, 4);
   exp::Expect::equals(#C2, 5);
@@ -39,6 +59,9 @@ static method main() → void {
   exp::Expect::equals(#C4, 6);
   exp::Expect::equals(#C5, 2);
   exp::Expect::equals(#C6, 2.{core::int::unary-}());
+  exp::Expect::equals(#C5, 2);
+  exp::Expect::equals(#C5, 2);
+  exp::Expect::equals(#C5, 2);
 }
 
 constants  {

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

@@ -11,6 +11,9 @@ static const field core::String var2 = #C3;
 static const field core::int var3 = #C4;
 static const field core::int var4 = #C5;
 static const field core::int var5 = #C6;
+static const field core::int var6 = #C5;
+static const field core::int var7 = #C5;
+static const field core::int var8 = #C5;
 static method function1(core::int a, core::int b) → core::int {
   core::int x = 1.{core::num::+}(a).{core::num::+}(b);
   return x;
@@ -32,6 +35,23 @@ static method function4() → core::int {
 static method function5() → core::int {
   return #C6;
 }
+static method function6() → core::int {
+  dynamic a;
+  a = 2;
+  return a as{TypeError,ForDynamic,ForNonNullableByDefault} core::int;
+}
+static method function7() → core::int {
+  dynamic a;
+  dynamic b;
+  a = 2;
+  return a as{TypeError,ForDynamic,ForNonNullableByDefault} core::int;
+}
+static method function8() → core::int {
+  dynamic a;
+  core::int? b;
+  a = 2;
+  return a as{TypeError,ForDynamic,ForNonNullableByDefault} core::int;
+}
 static method main() → void {
   exp::Expect::equals(#C1, 4);
   exp::Expect::equals(#C2, 5);
@@ -39,6 +59,9 @@ static method main() → void {
   exp::Expect::equals(#C4, 6);
   exp::Expect::equals(#C5, 2);
   exp::Expect::equals(#C6, 2.{core::int::unary-}());
+  exp::Expect::equals(#C5, 2);
+  exp::Expect::equals(#C5, 2);
+  exp::Expect::equals(#C5, 2);
 }
 
 constants  {
@@ -51,5 +74,5 @@ constants  {
 }
 
 Extra constant evaluation status:
-Evaluated: MethodInvocation @ org-dartlang-testcase:///const_functions_variable_declarations.dart:48:23 -> IntConstant(-2)
-Extra constant evaluation: evaluated: 21, effectively constant: 1
+Evaluated: MethodInvocation @ org-dartlang-testcase:///const_functions_variable_declarations.dart:71:23 -> IntConstant(-2)
+Extra constant evaluation: evaluated: 33, effectively constant: 1

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

@@ -11,4 +11,10 @@ const var4 = function4();
 int function4() {}
 const var5 = function5();
 int function5() {}
+const var6 = function6();
+int function6() {}
+const var7 = function7();
+int function7() {}
+const var8 = function8();
+int function8() {}
 void main() {}

pkg/front_end/testcases/const_functions/const_functions_variable_declarations.dart.textual_outline_modelled.expect

@@ -7,8 +7,14 @@ const var2 = function2();
 const var3 = function3();
 const var4 = function4();
 const var5 = function5();
+const var6 = function6();
+const var7 = function7();
+const var8 = function8();
 int function1(int a, int b) {}
 int function3() {}
 int function4() {}
 int function5() {}
+int function6() {}
+int function7() {}
+int function8() {}
 void main() {}

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

@@ -11,6 +11,9 @@ static const field core::String var2 = #C3;
 static const field core::int var3 = #C4;
 static const field core::int var4 = #C5;
 static const field core::int var5 = #C6;
+static const field core::int var6 = #C5;
+static const field core::int var7 = #C5;
+static const field core::int var8 = #C5;
 static method function1(core::int a, core::int b) → core::int {
   core::int x = 1.{core::num::+}(a).{core::num::+}(b);
   return x;
@@ -32,6 +35,23 @@ static method function4() → core::int {
 static method function5() → core::int {
   return #C6;
 }
+static method function6() → core::int {
+  dynamic a;
+  a = 2;
+  return a as{TypeError,ForDynamic,ForNonNullableByDefault} core::int;
+}
+static method function7() → core::int {
+  dynamic a;
+  dynamic b;
+  a = 2;
+  return a as{TypeError,ForDynamic,ForNonNullableByDefault} core::int;
+}
+static method function8() → core::int {
+  dynamic a;
+  core::int? b;
+  a = 2;
+  return a as{TypeError,ForDynamic,ForNonNullableByDefault} core::int;
+}
 static method main() → void {
   exp::Expect::equals(#C1, 4);
   exp::Expect::equals(#C2, 5);
@@ -39,6 +59,9 @@ static method main() → void {
   exp::Expect::equals(#C4, 6);
   exp::Expect::equals(#C5, 2);
   exp::Expect::equals(#C6, 2.{core::int::unary-}());
+  exp::Expect::equals(#C5, 2);
+  exp::Expect::equals(#C5, 2);
+  exp::Expect::equals(#C5, 2);
 }
 
 constants  {

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

@@ -10,6 +10,9 @@ static const field core::String var2 = self::function2();
 static const field core::int var3 = self::function3();
 static const field core::int var4 = self::function4();
 static const field core::int var5 = self::function5();
+static const field core::int var6 = self::function6();
+static const field core::int var7 = self::function7();
+static const field core::int var8 = self::function8();
 static method function1(core::int a, core::int b) → core::int
   ;
 static method function2() → core::String
@@ -20,5 +23,11 @@ static method function4() → core::int
   ;
 static method function5() → core::int
   ;
+static method function6() → core::int
+  ;
+static method function7() → core::int
+  ;
+static method function8() → core::int
+  ;
 static method main() → void
   ;

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

@@ -11,6 +11,9 @@ static const field core::String var2 = #C3;
 static const field core::int var3 = #C4;
 static const field core::int var4 = #C5;
 static const field core::int var5 = #C6;
+static const field core::int var6 = #C5;
+static const field core::int var7 = #C5;
+static const field core::int var8 = #C5;
 static method function1(core::int a, core::int b) → core::int {
   core::int x = 1.{core::num::+}(a).{core::num::+}(b);
   return x;
@@ -32,6 +35,23 @@ static method function4() → core::int {
 static method function5() → core::int {
   return #C6;
 }
+static method function6() → core::int {
+  dynamic a;
+  a = 2;
+  return a as{TypeError,ForDynamic,ForNonNullableByDefault} core::int;
+}
+static method function7() → core::int {
+  dynamic a;
+  dynamic b;
+  a = 2;
+  return a as{TypeError,ForDynamic,ForNonNullableByDefault} core::int;
+}
+static method function8() → core::int {
+  dynamic a;
+  core::int? b;
+  a = 2;
+  return a as{TypeError,ForDynamic,ForNonNullableByDefault} core::int;
+}
 static method main() → void {
   exp::Expect::equals(#C1, 4);
   exp::Expect::equals(#C2, 5);
@@ -39,6 +59,9 @@ static method main() → void {
   exp::Expect::equals(#C4, 6);
   exp::Expect::equals(#C5, 2);
   exp::Expect::equals(#C6, 2.{core::int::unary-}());
+  exp::Expect::equals(#C5, 2);
+  exp::Expect::equals(#C5, 2);
+  exp::Expect::equals(#C5, 2);
 }
 
 constants  {
@@ -51,5 +74,5 @@ constants  {
 }
 
 Extra constant evaluation status:
-Evaluated: MethodInvocation @ org-dartlang-testcase:///const_functions_variable_declarations.dart:48:23 -> IntConstant(-2)
-Extra constant evaluation: evaluated: 21, effectively constant: 1
+Evaluated: MethodInvocation @ org-dartlang-testcase:///const_functions_variable_declarations.dart:71:23 -> IntConstant(-2)
+Extra constant evaluation: evaluated: 33, effectively constant: 1

tests/language/const_functions/const_functions_variable_declarations_error_test.dart

@@ -0,0 +1,18 @@
+// Copyright (c) 2021, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Tests erroneous variable declaration usage within const functions.
+
+// SharedOptions=--enable-experiment=const-functions
+
+import "package:expect/expect.dart";
+
+const var1 = fn1();
+//           ^^^^^
+// [analyzer] COMPILE_TIME_ERROR.CONST_INITIALIZED_WITH_NON_CONSTANT_VALUE
+// [cfe] Constant evaluation error:
+int fn1() {
+  var a;
+  return a;
+}

tests/language/const_functions/const_functions_variable_declarations_test.dart

@@ -53,6 +53,35 @@ int function5() {
   return constant;
 }
 
+const var6 = function6();
+//           ^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.CONST_INITIALIZED_WITH_NON_CONSTANT_VALUE
+int function6() {
+  var a;
+  a = 2;
+  return a;
+}
+
+const var7 = function7();
+//           ^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.CONST_INITIALIZED_WITH_NON_CONSTANT_VALUE
+int function7() {
+  var a;
+  var b;
+  a = 2;
+  return a;
+}
+
+const var8 = function8();
+//           ^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.CONST_INITIALIZED_WITH_NON_CONSTANT_VALUE
+int function8() {
+  var a;
+  int? b;
+  a = 2;
+  return a;
+}
+
 void main() {
   Expect.equals(var1, 4);
   Expect.equals(var1_1, 5);
@@ -60,4 +89,7 @@ void main() {
   Expect.equals(var3, 6);
   Expect.equals(var4, 2);
   Expect.equals(var5, -2);
+  Expect.equals(var6, 2);
+  Expect.equals(var7, 2);
+  Expect.equals(var8, 2);
 }