Ensure that parenthesized function literals are deferred too.

When a function literal is wrapped in parentheses, it shouldn't affect
how it interacts with type inference.  This change ensures that
parenthesized function literals are treated the same as
unparenthesized ones by the logic that supports
dart-lang/language#731 (improved inference
for fold etc.)

Change-Id: I672787a31addbfe3f3282b6e638e00b693eea46f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/243000
Reviewed-by: Chloe Stefantsova <[email protected]>
Commit-Queue: Paul Berry <[email protected]>

Author: stereotype441

pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart

@@ -2462,8 +2462,12 @@ class TypeInferrerImpl implements TypeInferrer {
             "invocation.");
         continue;
       }
+      Expression unparenthesizedExpression = argumentExpression;
+      while (unparenthesizedExpression is ParenthesizedExpression) {
+        unparenthesizedExpression = unparenthesizedExpression.expression;
+      }
       if (isInferenceUpdate1Enabled &&
-          argumentExpression is FunctionExpression) {
+          unparenthesizedExpression is FunctionExpression) {
         (deferredFunctionLiterals ??= []).add(new _DeferredParamInfo(
             formalType: formalType,
             argumentExpression: argumentExpression,
@@ -5942,8 +5946,9 @@ class _DeferredParamInfo {
   /// argument.
   final DartType formalType;
 
-  /// The function literal expression.
-  final FunctionExpression argumentExpression;
+  /// The argument expression (possibly wrapped in an arbitrary number of
+  /// ParenthesizedExpressions).
+  final Expression argumentExpression;
 
   /// Indicates whether this is a named argument.
   final bool isNamed;

pkg/front_end/test/spell_checking_list_code.txt

@@ -1430,6 +1430,7 @@ unmark
 unneeded
 unordered
 unpaired
+unparenthesized
 unparsed
 unpleasant
 unqualified

pkg/front_end/testcases/inference_update_1/write_capture_deferral.dart

@@ -17,6 +17,24 @@ withUnnamedArguments(int? i, void Function(void Function(), Object?) f) {
   }
 }
 
+withUnnamedArgumentsParenthesized(int? i, void Function(void Function(), Object?) f) {
+  if (i != null) {
+    f((() {
+      i = null;
+    }), i);
+    i;
+  }
+}
+
+withUnnamedArgumentsParenthesizedTwice(int? i, void Function(void Function(), Object?) f) {
+  if (i != null) {
+    f(((() {
+      i = null;
+    })), i);
+    i;
+  }
+}
+
 withNamedArguments(
     int? i, void Function({required void Function() g, Object? x}) f) {
   if (i != null) {
@@ -29,6 +47,30 @@ withNamedArguments(
   }
 }
 
+withNamedArgumentsParenthesized(
+    int? i, void Function({required void Function() g, Object? x}) f) {
+  if (i != null) {
+    f(
+        g: (() {
+          i = null;
+        }),
+        x: i);
+    i;
+  }
+}
+
+withNamedArgumentsParenthesizedTwice(
+    int? i, void Function({required void Function() g, Object? x}) f) {
+  if (i != null) {
+    f(
+        g: ((() {
+          i = null;
+        })),
+        x: i);
+    i;
+  }
+}
+
 withIdentical_lhs(int? i) {
   if (i != null) {
     i;

pkg/front_end/testcases/inference_update_1/write_capture_deferral.dart.textual_outline.expect

@@ -1,6 +1,14 @@
 withUnnamedArguments(int? i, void Function(void Function(), Object?) f) {}
+withUnnamedArgumentsParenthesized(
+    int? i, void Function(void Function(), Object?) f) {}
+withUnnamedArgumentsParenthesizedTwice(
+    int? i, void Function(void Function(), Object?) f) {}
 withNamedArguments(
     int? i, void Function({required void Function() g, Object? x}) f) {}
+withNamedArgumentsParenthesized(
+    int? i, void Function({required void Function() g, Object? x}) f) {}
+withNamedArgumentsParenthesizedTwice(
+    int? i, void Function({required void Function() g, Object? x}) f) {}
 withIdentical_lhs(int? i) {}
 withIdentical_rhs(int? i) {}
 

pkg/front_end/testcases/inference_update_1/write_capture_deferral.dart.textual_outline_modelled.expect

@@ -18,4 +18,12 @@ withIdentical_lhs(int? i) {}
 withIdentical_rhs(int? i) {}
 withNamedArguments(
     int? i, void Function({required void Function() g, Object? x}) f) {}
+withNamedArgumentsParenthesized(
+    int? i, void Function({required void Function() g, Object? x}) f) {}
+withNamedArgumentsParenthesizedTwice(
+    int? i, void Function({required void Function() g, Object? x}) f) {}
 withUnnamedArguments(int? i, void Function(void Function(), Object?) f) {}
+withUnnamedArgumentsParenthesized(
+    int? i, void Function(void Function(), Object?) f) {}
+withUnnamedArgumentsParenthesizedTwice(
+    int? i, void Function(void Function(), Object?) f) {}

pkg/front_end/testcases/inference_update_1/write_capture_deferral.dart.weak.expect

@@ -27,6 +27,22 @@ static method withUnnamedArguments(core::int? i, (() → void, core::Object?) 
     i;
   }
 }
+static method withUnnamedArgumentsParenthesized(core::int? i, (() → void, core::Object?) → void f) → dynamic {
+  if(!(i == null)) {
+    f(() → void {
+      i = null;
+    }, i{core::int}){(() → void, core::Object?) → void};
+    i;
+  }
+}
+static method withUnnamedArgumentsParenthesizedTwice(core::int? i, (() → void, core::Object?) → void f) → dynamic {
+  if(!(i == null)) {
+    f(() → void {
+      i = null;
+    }, i{core::int}){(() → void, core::Object?) → void};
+    i;
+  }
+}
 static method withNamedArguments(core::int? i, ({required g: () → void, x: core::Object?}) → void f) → dynamic {
   if(!(i == null)) {
     f(g: () → void {
@@ -35,6 +51,22 @@ static method withNamedArguments(core::int? i, ({required g: () → void, x: cor
     i;
   }
 }
+static method withNamedArgumentsParenthesized(core::int? i, ({required g: () → void, x: core::Object?}) → void f) → dynamic {
+  if(!(i == null)) {
+    f(g: () → void {
+      i = null;
+    }, x: i{core::int}){({required g: () → void, x: core::Object?}) → void};
+    i;
+  }
+}
+static method withNamedArgumentsParenthesizedTwice(core::int? i, ({required g: () → void, x: core::Object?}) → void f) → dynamic {
+  if(!(i == null)) {
+    f(g: () → void {
+      i = null;
+    }, x: i{core::int}){({required g: () → void, x: core::Object?}) → void};
+    i;
+  }
+}
 static method withIdentical_lhs(core::int? i) → dynamic {
   if(!(i == null)) {
     i{core::int};

pkg/front_end/testcases/inference_update_1/write_capture_deferral.dart.weak.modular.expect

@@ -27,6 +27,22 @@ static method withUnnamedArguments(core::int? i, (() → void, core::Object?) 
     i;
   }
 }
+static method withUnnamedArgumentsParenthesized(core::int? i, (() → void, core::Object?) → void f) → dynamic {
+  if(!(i == null)) {
+    f(() → void {
+      i = null;
+    }, i{core::int}){(() → void, core::Object?) → void};
+    i;
+  }
+}
+static method withUnnamedArgumentsParenthesizedTwice(core::int? i, (() → void, core::Object?) → void f) → dynamic {
+  if(!(i == null)) {
+    f(() → void {
+      i = null;
+    }, i{core::int}){(() → void, core::Object?) → void};
+    i;
+  }
+}
 static method withNamedArguments(core::int? i, ({required g: () → void, x: core::Object?}) → void f) → dynamic {
   if(!(i == null)) {
     f(g: () → void {
@@ -35,6 +51,22 @@ static method withNamedArguments(core::int? i, ({required g: () → void, x: cor
     i;
   }
 }
+static method withNamedArgumentsParenthesized(core::int? i, ({required g: () → void, x: core::Object?}) → void f) → dynamic {
+  if(!(i == null)) {
+    f(g: () → void {
+      i = null;
+    }, x: i{core::int}){({required g: () → void, x: core::Object?}) → void};
+    i;
+  }
+}
+static method withNamedArgumentsParenthesizedTwice(core::int? i, ({required g: () → void, x: core::Object?}) → void f) → dynamic {
+  if(!(i == null)) {
+    f(g: () → void {
+      i = null;
+    }, x: i{core::int}){({required g: () → void, x: core::Object?}) → void};
+    i;
+  }
+}
 static method withIdentical_lhs(core::int? i) → dynamic {
   if(!(i == null)) {
     i{core::int};

pkg/front_end/testcases/inference_update_1/write_capture_deferral.dart.weak.outline.expect

@@ -14,8 +14,16 @@ class C extends self::B {
 }
 static method withUnnamedArguments(core::int? i, (() → void, core::Object?) → void f) → dynamic
   ;
+static method withUnnamedArgumentsParenthesized(core::int? i, (() → void, core::Object?) → void f) → dynamic
+  ;
+static method withUnnamedArgumentsParenthesizedTwice(core::int? i, (() → void, core::Object?) → void f) → dynamic
+  ;
 static method withNamedArguments(core::int? i, ({required g: () → void, x: core::Object?}) → void f) → dynamic
   ;
+static method withNamedArgumentsParenthesized(core::int? i, ({required g: () → void, x: core::Object?}) → void f) → dynamic
+  ;
+static method withNamedArgumentsParenthesizedTwice(core::int? i, ({required g: () → void, x: core::Object?}) → void f) → dynamic
+  ;
 static method withIdentical_lhs(core::int? i) → dynamic
   ;
 static method withIdentical_rhs(core::int? i) → dynamic

pkg/front_end/testcases/inference_update_1/write_capture_deferral.dart.weak.transformed.expect

@@ -27,6 +27,22 @@ static method withUnnamedArguments(core::int? i, (() → void, core::Object?) 
     i;
   }
 }
+static method withUnnamedArgumentsParenthesized(core::int? i, (() → void, core::Object?) → void f) → dynamic {
+  if(!(i == null)) {
+    f(() → void {
+      i = null;
+    }, i{core::int}){(() → void, core::Object?) → void};
+    i;
+  }
+}
+static method withUnnamedArgumentsParenthesizedTwice(core::int? i, (() → void, core::Object?) → void f) → dynamic {
+  if(!(i == null)) {
+    f(() → void {
+      i = null;
+    }, i{core::int}){(() → void, core::Object?) → void};
+    i;
+  }
+}
 static method withNamedArguments(core::int? i, ({required g: () → void, x: core::Object?}) → void f) → dynamic {
   if(!(i == null)) {
     f(g: () → void {
@@ -35,6 +51,22 @@ static method withNamedArguments(core::int? i, ({required g: () → void, x: cor
     i;
   }
 }
+static method withNamedArgumentsParenthesized(core::int? i, ({required g: () → void, x: core::Object?}) → void f) → dynamic {
+  if(!(i == null)) {
+    f(g: () → void {
+      i = null;
+    }, x: i{core::int}){({required g: () → void, x: core::Object?}) → void};
+    i;
+  }
+}
+static method withNamedArgumentsParenthesizedTwice(core::int? i, ({required g: () → void, x: core::Object?}) → void f) → dynamic {
+  if(!(i == null)) {
+    f(g: () → void {
+      i = null;
+    }, x: i{core::int}){({required g: () → void, x: core::Object?}) → void};
+    i;
+  }
+}
 static method withIdentical_lhs(core::int? i) → dynamic {
   if(!(i == null)) {
     i{core::int};

tests/language/inference_update_1/write_capture_deferral_enabled_test.dart

@@ -21,6 +21,26 @@ withUnnamedArguments(int? i, void Function(void Function(), Object?) f) {
   }
 }
 
+withUnnamedArgumentsParenthesized(
+    int? i, void Function(void Function(), Object?) f) {
+  if (i != null) {
+    f((() {
+      i = null;
+    }), i..expectStaticType<Exactly<int>>());
+    i..expectStaticType<Exactly<int?>>();
+  }
+}
+
+withUnnamedArgumentsParenthesizedTwice(
+    int? i, void Function(void Function(), Object?) f) {
+  if (i != null) {
+    f(((() {
+      i = null;
+    })), i..expectStaticType<Exactly<int>>());
+    i..expectStaticType<Exactly<int?>>();
+  }
+}
+
 withNamedArguments(
     int? i, void Function({required void Function() g, Object? x}) f) {
   if (i != null) {
@@ -33,6 +53,30 @@ withNamedArguments(
   }
 }
 
+withNamedArgumentsParenthesized(
+    int? i, void Function({required void Function() g, Object? x}) f) {
+  if (i != null) {
+    f(
+        g: (() {
+          i = null;
+        }),
+        x: i..expectStaticType<Exactly<int>>());
+    i..expectStaticType<Exactly<int?>>();
+  }
+}
+
+withNamedArgumentsParenthesizedTwice(
+    int? i, void Function({required void Function() g, Object? x}) f) {
+  if (i != null) {
+    f(
+        g: ((() {
+          i = null;
+        })),
+        x: i..expectStaticType<Exactly<int>>());
+    i..expectStaticType<Exactly<int?>>();
+  }
+}
+
 withIdentical_lhs(int? i) {
   if (i != null) {
     i..expectStaticType<Exactly<int>>();