[cfe] Implement dispatchPatternSchema

Part of #49749

Change-Id: I9fa3ad41501422990d47bc637d46cbd22fdb54fb
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/277004
Reviewed-by: Johnni Winther <[email protected]>
Commit-Queue: Chloe Stefantsova <[email protected]>

Author: chloestefantsova

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

@@ -9606,11 +9606,63 @@ class InferenceVisitorImpl extends InferenceVisitorBase
   }
 
   @override
-  DartType dispatchPatternSchema(TreeNode node) {
-    // The front end's representation of a switch cases currently doesn't have
-    // any support for patterns; each case is represented as an expression.  So
-    // analyze it as a constant pattern.
-    return analyzeConstantPatternSchema();
+  DartType dispatchPatternSchema(Node node) {
+    if (node is AndPattern) {
+      return analyzeLogicalAndPatternSchema(node.left, node.right);
+    } else if (node is AssignedVariablePattern) {
+      return analyzeAssignedVariablePatternSchema(node.variable);
+    } else if (node is CastPattern) {
+      return analyzeCastPatternSchema();
+    } else if (node is ConstantPattern) {
+      return analyzeConstantPatternSchema();
+    } else if (node is ListPattern) {
+      return analyzeListPatternSchema(
+          elementType: node.typeArgument, elements: node.patterns);
+    } else if (node is MapPattern) {
+      return analyzeMapPatternSchema(
+          typeArguments: node.keyType != null && node.valueType != null
+              ? new MapPatternTypeArguments<DartType>(
+                  keyType: node.keyType!, valueType: node.valueType!)
+              : null,
+          elements: node.entries);
+    } else if (node is NamedPattern) {
+      return dispatchPatternSchema(node.pattern);
+    } else if (node is NullAssertPattern) {
+      return analyzeNullCheckOrAssertPatternSchema(node.pattern,
+          isAssert: true);
+    } else if (node is NullCheckPattern) {
+      return analyzeNullCheckOrAssertPatternSchema(node.pattern,
+          isAssert: false);
+    } else if (node is ObjectPattern) {
+      return analyzeObjectPatternSchema(node.type);
+    } else if (node is OrPattern) {
+      return analyzeLogicalOrPatternSchema(node.left, node.right);
+    } else if (node is RecordPattern) {
+      return analyzeRecordPatternSchema(
+          fields: <RecordPatternField<TreeNode, Pattern>>[
+            for (Pattern element in node.patterns)
+              if (element is NamedPattern)
+                new RecordPatternField<TreeNode, Pattern>(
+                    node: element, name: element.name, pattern: element.pattern)
+              else
+                new RecordPatternField<TreeNode, Pattern>(
+                    node: element, name: null, pattern: element)
+          ]);
+    } else if (node is RelationalPattern) {
+      return analyzeRelationalPatternSchema();
+    } else if (node is RestPattern) {
+      // This pattern can't appear on it's own.
+      return const InvalidType();
+    } else if (node is VariablePattern) {
+      return analyzeDeclaredVariablePatternSchema(node.type);
+    } else if (node is WildcardPattern) {
+      return analyzeDeclaredVariablePatternSchema(node.type);
+    } else if (node is InvalidPattern) {
+      return const InvalidType();
+    } else {
+      return problems.unhandled("${node.runtimeType}", "dispatchPatternSchema",
+          node is TreeNode ? node.fileOffset : TreeNode.noOffset, helper.uri);
+    }
   }
 
   @override

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

@@ -517,7 +517,8 @@ class OperationsCfe
 
   @override
   DartType glb(DartType type1, DartType type2) {
-    throw new UnimplementedError('TODO(paulberry)');
+    return typeEnvironment.getStandardLowerBound(type1, type2,
+        isNonNullableByDefault: true);
   }
 
   @override
@@ -546,7 +547,7 @@ class OperationsCfe
 
   @override
   DartType makeNullable(DartType type) {
-    throw new UnimplementedError('TODO(paulberry)');
+    return type.withDeclaredNullability(Nullability.nullable);
   }
 
   @override
@@ -600,8 +601,18 @@ class OperationsCfe
 
   @override
   DartType? matchIterableType(DartType type) {
-    // TODO(scheglov): implement matchIterableType
-    throw new UnimplementedError('TODO(scheglov)');
+    if (type is! InterfaceType) {
+      return null;
+    } else {
+      InterfaceType? interfaceType = typeEnvironment.getTypeAsInstanceOf(type,
+          typeEnvironment.coreTypes.iterableClass, typeEnvironment.coreTypes,
+          isNonNullableByDefault: isNonNullableByDefault);
+      if (interfaceType == null) {
+        return null;
+      } else {
+        return interfaceType.typeArguments.single;
+      }
+    }
   }
 }
 

pkg/front_end/testcases/patterns/pattern_schema_affects_inferred_expression_type.dart

@@ -0,0 +1,17 @@
+// Copyright (c) 2023, 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.
+
+class A {
+  int get foo => 0;
+}
+
+List<T> foo<T>(void Function(T) f) => throw 0;
+
+test1() {
+  var <A>[var x] = foo((a) => a.foo);
+}
+
+test2() {
+  var [var x, ...y] = foo((e) => e);
+}

pkg/front_end/testcases/patterns/pattern_schema_affects_inferred_expression_type.dart.strong.expect

@@ -0,0 +1,35 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+import "dart:_internal" as _in;
+
+class A extends core::Object {
+  synthetic constructor •() → self::A
+    : super core::Object::•()
+    ;
+  get foo() → core::int
+    return 0;
+}
+static method foo<T extends core::Object? = dynamic>((self::foo::T%) → void f) → core::List<self::foo::T%>
+  return throw 0;
+static method test1() → dynamic {
+  self::A x;
+  {
+    final dynamic #0#0 = self::foo<self::A>((self::A a) → void => a.{self::A::foo}{core::int});
+    if(!(#0#0{core::List<self::A>}.{core::List::length}{core::int} =={core::num::==}{(core::Object) → core::bool} #C1 && (let final dynamic #t1 = x = #0#0{core::List<self::A>}.{core::List::[]}(0){(core::int) → self::A} in true)))
+      throw new _in::ReachabilityError::•();
+  }
+}
+static method test2() → dynamic {
+  core::Object? x;
+  core::List<core::Object?> y;
+  {
+    final dynamic #0#0 = self::foo<core::Object?>((core::Object? e) → void => e);
+    if(!(#0#0{core::List<core::Object?>}.{core::List::length}{core::int}.{core::num::>=}(#C1){(core::num) → core::bool} && (let final dynamic #t2 = x = #0#0{core::List<core::Object?>}.{core::List::[]}(0){(core::int) → core::Object?} in true) && (let final dynamic #t3 = y = #0#0{core::List<core::Object?>}.{core::List::sublist}(1){(core::int, [core::int?]) → core::List<core::Object?>} in true)))
+      throw new _in::ReachabilityError::•();
+  }
+}
+
+constants  {
+  #C1 = 1
+}

pkg/front_end/testcases/patterns/pattern_schema_affects_inferred_expression_type.dart.strong.transformed.expect

@@ -0,0 +1,35 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+import "dart:_internal" as _in;
+
+class A extends core::Object {
+  synthetic constructor •() → self::A
+    : super core::Object::•()
+    ;
+  get foo() → core::int
+    return 0;
+}
+static method foo<T extends core::Object? = dynamic>((self::foo::T%) → void f) → core::List<self::foo::T%>
+  return throw 0;
+static method test1() → dynamic {
+  self::A x;
+  {
+    final dynamic #0#0 = self::foo<self::A>((self::A a) → void => a.{self::A::foo}{core::int});
+    if(!(#0#0{core::List<self::A>}.{core::List::length}{core::int} =={core::num::==}{(core::Object) → core::bool} #C1 && (let final self::A #t1 = x = #0#0{core::List<self::A>}.{core::List::[]}(0){(core::int) → self::A} in true)))
+      throw new _in::ReachabilityError::•();
+  }
+}
+static method test2() → dynamic {
+  core::Object? x;
+  core::List<core::Object?> y;
+  {
+    final dynamic #0#0 = self::foo<core::Object?>((core::Object? e) → void => e);
+    if(!(#0#0{core::List<core::Object?>}.{core::List::length}{core::int}.{core::num::>=}(#C1){(core::num) → core::bool} && (let final core::Object? #t2 = x = #0#0{core::List<core::Object?>}.{core::List::[]}(0){(core::int) → core::Object?} in true) && (let final core::List<core::Object?> #t3 = y = #0#0{core::List<core::Object?>}.{core::List::sublist}(1){(core::int, [core::int?]) → core::List<core::Object?>} in true)))
+      throw new _in::ReachabilityError::•();
+  }
+}
+
+constants  {
+  #C1 = 1
+}

pkg/front_end/testcases/patterns/pattern_schema_affects_inferred_expression_type.dart.textual_outline.expect

@@ -0,0 +1,7 @@
+class A {
+  int get foo => 0;
+}
+
+List<T> foo<T>(void Function(T) f) => throw 0;
+test1() {}
+test2() {}

pkg/front_end/testcases/patterns/pattern_schema_affects_inferred_expression_type.dart.textual_outline_modelled.expect

@@ -0,0 +1,8 @@
+List<T> foo<T>(void Function(T) f) => throw 0;
+
+class A {
+  int get foo => 0;
+}
+
+test1() {}
+test2() {}

pkg/front_end/testcases/patterns/pattern_schema_affects_inferred_expression_type.dart.weak.expect

@@ -0,0 +1,35 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+import "dart:_internal" as _in;
+
+class A extends core::Object {
+  synthetic constructor •() → self::A
+    : super core::Object::•()
+    ;
+  get foo() → core::int
+    return 0;
+}
+static method foo<T extends core::Object? = dynamic>((self::foo::T%) → void f) → core::List<self::foo::T%>
+  return throw 0;
+static method test1() → dynamic {
+  self::A x;
+  {
+    final dynamic #0#0 = self::foo<self::A>((self::A a) → void => a.{self::A::foo}{core::int});
+    if(!(#0#0{core::List<self::A>}.{core::List::length}{core::int} =={core::num::==}{(core::Object) → core::bool} #C1 && (let final dynamic #t1 = x = #0#0{core::List<self::A>}.{core::List::[]}(0){(core::int) → self::A} in true)))
+      throw new _in::ReachabilityError::•();
+  }
+}
+static method test2() → dynamic {
+  core::Object? x;
+  core::List<core::Object?> y;
+  {
+    final dynamic #0#0 = self::foo<core::Object?>((core::Object? e) → void => e);
+    if(!(#0#0{core::List<core::Object?>}.{core::List::length}{core::int}.{core::num::>=}(#C1){(core::num) → core::bool} && (let final dynamic #t2 = x = #0#0{core::List<core::Object?>}.{core::List::[]}(0){(core::int) → core::Object?} in true) && (let final dynamic #t3 = y = #0#0{core::List<core::Object?>}.{core::List::sublist}(1){(core::int, [core::int?]) → core::List<core::Object?>} in true)))
+      throw new _in::ReachabilityError::•();
+  }
+}
+
+constants  {
+  #C1 = 1
+}

pkg/front_end/testcases/patterns/pattern_schema_affects_inferred_expression_type.dart.weak.modular.expect

@@ -0,0 +1,35 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+import "dart:_internal" as _in;
+
+class A extends core::Object {
+  synthetic constructor •() → self::A
+    : super core::Object::•()
+    ;
+  get foo() → core::int
+    return 0;
+}
+static method foo<T extends core::Object? = dynamic>((self::foo::T%) → void f) → core::List<self::foo::T%>
+  return throw 0;
+static method test1() → dynamic {
+  self::A x;
+  {
+    final dynamic #0#0 = self::foo<self::A>((self::A a) → void => a.{self::A::foo}{core::int});
+    if(!(#0#0{core::List<self::A>}.{core::List::length}{core::int} =={core::num::==}{(core::Object) → core::bool} #C1 && (let final dynamic #t1 = x = #0#0{core::List<self::A>}.{core::List::[]}(0){(core::int) → self::A} in true)))
+      throw new _in::ReachabilityError::•();
+  }
+}
+static method test2() → dynamic {
+  core::Object? x;
+  core::List<core::Object?> y;
+  {
+    final dynamic #0#0 = self::foo<core::Object?>((core::Object? e) → void => e);
+    if(!(#0#0{core::List<core::Object?>}.{core::List::length}{core::int}.{core::num::>=}(#C1){(core::num) → core::bool} && (let final dynamic #t2 = x = #0#0{core::List<core::Object?>}.{core::List::[]}(0){(core::int) → core::Object?} in true) && (let final dynamic #t3 = y = #0#0{core::List<core::Object?>}.{core::List::sublist}(1){(core::int, [core::int?]) → core::List<core::Object?>} in true)))
+      throw new _in::ReachabilityError::•();
+  }
+}
+
+constants  {
+  #C1 = 1
+}

pkg/front_end/testcases/patterns/pattern_schema_affects_inferred_expression_type.dart.weak.outline.expect

@@ -0,0 +1,16 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+class A extends core::Object {
+  synthetic constructor •() → self::A
+    ;
+  get foo() → core::int
+    ;
+}
+static method foo<T extends core::Object? = dynamic>((self::foo::T%) → void f) → core::List<self::foo::T%>
+  ;
+static method test1() → dynamic
+  ;
+static method test2() → dynamic
+  ;

pkg/front_end/testcases/patterns/pattern_schema_affects_inferred_expression_type.dart.weak.transformed.expect

@@ -0,0 +1,35 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+import "dart:_internal" as _in;
+
+class A extends core::Object {
+  synthetic constructor •() → self::A
+    : super core::Object::•()
+    ;
+  get foo() → core::int
+    return 0;
+}
+static method foo<T extends core::Object? = dynamic>((self::foo::T%) → void f) → core::List<self::foo::T%>
+  return throw 0;
+static method test1() → dynamic {
+  self::A x;
+  {
+    final dynamic #0#0 = self::foo<self::A>((self::A a) → void => a.{self::A::foo}{core::int});
+    if(!(#0#0{core::List<self::A>}.{core::List::length}{core::int} =={core::num::==}{(core::Object) → core::bool} #C1 && (let final self::A #t1 = x = #0#0{core::List<self::A>}.{core::List::[]}(0){(core::int) → self::A} in true)))
+      throw new _in::ReachabilityError::•();
+  }
+}
+static method test2() → dynamic {
+  core::Object? x;
+  core::List<core::Object?> y;
+  {
+    final dynamic #0#0 = self::foo<core::Object?>((core::Object? e) → void => e);
+    if(!(#0#0{core::List<core::Object?>}.{core::List::length}{core::int}.{core::num::>=}(#C1){(core::num) → core::bool} && (let final core::Object? #t2 = x = #0#0{core::List<core::Object?>}.{core::List::[]}(0){(core::int) → core::Object?} in true) && (let final core::List<core::Object?> #t3 = y = #0#0{core::List<core::Object?>}.{core::List::sublist}(1){(core::int, [core::int?]) → core::List<core::Object?>} in true)))
+      throw new _in::ReachabilityError::•();
+  }
+}
+
+constants  {
+  #C1 = 1
+}