[_fe_shared_analyzer] Handle remaining patterns in exhaustiveness

This adds explicit handling of the remaining patterns in exhaustiveness.
All these patterns are handled trivially but with TODOs for where we might
want to improve handling.

Asserts are added to flag if a pattern is unhandled.

Change-Id: I82bfccda396316c718685b4d810f259c25771f00
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/285321
Commit-Queue: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Paul Berry <paulberry@google.com>

pkg/_fe_analyzer_shared/test/exhaustiveness/data/and_pattern.dart

@@ -0,0 +1,23 @@
+// 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 {}
+
+and(A o1, A o2) {
+  var a = /*
+   fields={hashCode:int,runtimeType:Type},
+   type=A
+  */switch (o1) {
+    A() && var a /*space=??*/=> 0,
+    _ /*space=()*/=> 1,
+  };
+
+  var b = /*
+   error=non-exhaustive:A,
+   fields={hashCode:int,runtimeType:Type},
+   type=A
+  */switch (o1) {
+    A() && var a /*space=??*/=> 0,
+  };
+}

pkg/_fe_analyzer_shared/test/exhaustiveness/data/cast.dart

@@ -0,0 +1,51 @@
+// 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 field;
+
+  A(this.field);
+}
+
+simpleCast(o1, o2) {
+  var a = /*
+   fields={},
+   subtypes={Object,Null},
+   type=Object?
+  */switch (o1) {
+    _ as A /*space=??*/=> 0,
+    _ /*space=()*/=> 1
+  };
+
+  var b = /*
+   error=non-exhaustive:Object,
+   fields={},
+   subtypes={Object,Null},
+   type=Object?
+  */switch (o2) {
+    _ as A /*space=??*/=> 0,
+  };
+}
+
+restrictedCase(o1, o2) {
+  // Cast shouldn't match everything, because even though it doesn't throw,
+  // it might not match.
+  var a = /*
+   fields={},
+   subtypes={Object,Null},
+   type=Object?
+  */switch (o1) {
+    A(field: 42) as A /*space=??*/=> 0,
+    _ /*space=()*/=> 1
+  };
+
+  var b = /*
+   error=non-exhaustive:Object,
+   fields={},
+   subtypes={Object,Null},
+   type=Object?
+  */switch (o2) {
+    A(field: 42) as A /*space=??*/=> 0,
+  };
+}

pkg/_fe_analyzer_shared/test/exhaustiveness/data/list.dart

@@ -0,0 +1,68 @@
+// 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.
+
+untypedList(List list) {
+  var a = /*cfe.
+   error=non-exhaustive:List<dynamic>,
+   fields={first:Object?,hashCode:int,isEmpty:bool,isNotEmpty:bool,iterator:Iterator<dynamic>,last:Object?,length:int,reversed:Iterable<dynamic>,runtimeType:Type,single:Object?},
+   type=List<dynamic>
+  *//*analyzer.
+   error=non-exhaustive:List<dynamic>,
+   fields={first:Object?,hashCode:int,isEmpty:bool,isNotEmpty:bool,iterator:Iterator<dynamic>,last:Object?,length:int,runtimeType:Type},
+   type=List<dynamic>
+  */switch (list) {
+    [] /*space=??*/=> 0,
+    [_] /*space=??*/=> 1,
+    [_, _] /*space=??*/=> 2,
+    [_, ..., _] /*space=??*/=> 3,
+  };
+}
+
+sealed class A {}
+class B extends A {}
+class C extends A {}
+
+typedList(List<A> list) {
+  var a = /*cfe.
+   error=non-exhaustive:List<A>,
+   fields={first:A,hashCode:int,isEmpty:bool,isNotEmpty:bool,iterator:Iterator<A>,last:A,length:int,reversed:Iterable<A>,runtimeType:Type,single:A},
+   type=List<A>
+  *//*analyzer.
+   error=non-exhaustive:List<A>,
+   fields={first:A,hashCode:int,isEmpty:bool,isNotEmpty:bool,iterator:Iterator<A>,last:A,length:int,runtimeType:Type},
+   type=List<A>
+  */switch (list) {
+    [] /*space=??*/=> 0,
+    [B b] /*space=??*/=> 1,
+    [C c] /*space=??*/=> 2,
+    [_, _] /*space=??*/=> 3,
+    [B b, ..., _] /*space=??*/=> 4,
+    [C c, ..., _] /*space=??*/=> 5,
+  };
+}
+
+restWithSubpattern(List list) {
+  var a = /*cfe.
+   error=non-exhaustive:List<dynamic>,
+   fields={first:Object?,hashCode:int,isEmpty:bool,isNotEmpty:bool,iterator:Iterator<dynamic>,last:Object?,length:int,reversed:Iterable<dynamic>,runtimeType:Type,single:Object?},
+   type=List<dynamic>
+  *//*analyzer.
+   error=non-exhaustive:List<dynamic>,
+   fields={first:Object?,hashCode:int,isEmpty:bool,isNotEmpty:bool,iterator:Iterator<dynamic>,last:Object?,length:int,runtimeType:Type},
+   type=List<dynamic>
+  */switch (list) {
+    [...var l] /*space=??*/=> l.length,
+  };
+  var b = /*cfe.
+   error=non-exhaustive:List<dynamic>,
+   fields={first:Object?,hashCode:int,isEmpty:bool,isNotEmpty:bool,iterator:Iterator<dynamic>,last:Object?,length:int,reversed:Iterable<dynamic>,runtimeType:Type,single:Object?},
+   type=List<dynamic>
+  *//*analyzer.
+   error=non-exhaustive:List<dynamic>,
+   fields={first:Object?,hashCode:int,isEmpty:bool,isNotEmpty:bool,iterator:Iterator<dynamic>,last:Object?,length:int,runtimeType:Type},
+   type=List<dynamic>
+  */switch (list) {
+    [...List<String> l] /*space=??*/=> l.length,
+  };
+}

pkg/_fe_analyzer_shared/test/exhaustiveness/data/map.dart

@@ -0,0 +1,44 @@
+// 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.
+
+untypedMap(Map map) {
+  var a = /*cfe.
+   error=non-exhaustive:Map<dynamic, dynamic>,
+   fields={entries:Iterable<MapEntry<dynamic, dynamic>>,hashCode:int,isEmpty:bool,isNotEmpty:bool,keys:Iterable<dynamic>,length:int,runtimeType:Type,values:Iterable<dynamic>},
+   type=Map<dynamic, dynamic>
+  *//*analyzer.
+   error=non-exhaustive:Map<dynamic, dynamic>,
+   fields={hashCode:int,isEmpty:bool,isNotEmpty:bool,keys:Iterable<dynamic>,length:int,runtimeType:Type,values:Iterable<dynamic>},
+   type=Map<dynamic, dynamic>
+  */switch (map) {
+    {} /*space=??*/=> 0,
+    {1: _} /*space=??*/=> 1,
+    [1: _, 2: _] /*space=??*/=> 2,
+    [1: _, ..., _] /*space=??*/=> 3,
+    {...} /*space=??*/=> 4:
+  };
+}
+
+sealed class A {}
+class B extends A {}
+class C extends A {}
+
+typedList(List<A> list) {
+  var a = /*cfe.
+   error=non-exhaustive:List<A>,
+   fields={first:A,hashCode:int,isEmpty:bool,isNotEmpty:bool,iterator:Iterator<A>,last:A,length:int,reversed:Iterable<A>,runtimeType:Type,single:A},
+   type=List<A>
+  *//*analyzer.
+   error=non-exhaustive:List<A>,
+   fields={first:A,hashCode:int,isEmpty:bool,isNotEmpty:bool,iterator:Iterator<A>,last:A,length:int,runtimeType:Type},
+   type=List<A>
+  */switch (list) {
+    [] /*space=??*/=> 0,
+    [B b] /*space=??*/=> 1,
+    [C c] /*space=??*/=> 2,
+    [_, _] /*space=??*/=> 3,
+    [B b, ... _] /*space=??*/=> 4,
+    [C c, ... _] /*space=??*/=> 5,
+  };
+}

pkg/_fe_analyzer_shared/test/exhaustiveness/data/null_assert.dart

@@ -0,0 +1,51 @@
+// 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 field;
+
+  A(this.field);
+}
+
+simpleAssert(o1, o2) {
+  var a = /*
+   fields={},
+   subtypes={Object,Null},
+   type=Object?
+  */switch (o1) {
+    _! /*space=??*/=> 0,
+    _ /*space=()*/=> 1
+  };
+
+  var b = /*
+   error=non-exhaustive:Object,
+   fields={},
+   subtypes={Object,Null},
+   type=Object?
+  */switch (o2) {
+    _! /*space=??*/=> 0,
+  };
+}
+
+restrictedCase(o1, o2) {
+  // Null assert shouldn't match everything, because even though it doesn't
+  // throw, it might not match.
+  var a = /*
+   fields={},
+   subtypes={Object,Null},
+   type=Object?
+  */switch (o1) {
+    A(field: 42)! /*space=??*/=> 0,
+    _ /*space=()*/=> 1
+  };
+
+  var b = /*
+   error=non-exhaustive:Object,
+   fields={},
+   subtypes={Object,Null},
+   type=Object?
+  */switch (o2) {
+    A(field: 42)! /*space=??*/=> 0,
+  };
+}

pkg/_fe_analyzer_shared/test/exhaustiveness/data/relational.dart

@@ -0,0 +1,43 @@
+// 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.
+
+equals(o1, o2) {
+  var a = /*
+   fields={},
+   subtypes={Object,Null},
+   type=Object?
+  */switch (o1) {
+    == 0 /*space=??*/=> 0,
+    _ /*space=()*/=> 1
+  };
+
+  var b = /*
+   error=non-exhaustive:Object,
+   fields={},
+   subtypes={Object,Null},
+   type=Object?
+  */switch (o2) {
+    == 0 /*space=??*/=> 0,
+  };
+}
+
+greaterThan(o1, o2) {
+  var a = /*
+   fields={},
+   subtypes={Object,Null},
+   type=Object?
+  */switch (o1) {
+    >= 0 /*space=??*/=> 0,
+    _ /*space=()*/=> 1
+  };
+
+  var b = /*
+   error=non-exhaustive:Object,
+   fields={},
+   subtypes={Object,Null},
+   type=Object?
+  */switch (o2) {
+    >= 0 /*space=??*/=> 0,
+  };
+}

pkg/analyzer/lib/src/generated/exhaustiveness.dart

@@ -20,36 +20,30 @@ import 'package:analyzer/src/dart/resolver/variance.dart';
 import 'package:analyzer/src/generated/constant.dart';
 
 Space convertConstantValueToSpace(
-    AnalyzerExhaustivenessCache cache, DartObjectImpl? constantValue) {
-  if (constantValue != null) {
-    InstanceState state = constantValue.state;
-    if (constantValue.isNull) {
-      return Space.nullSpace;
-    } else if (state is BoolState && state.value != null) {
-      return Space(cache.getBoolValueStaticType(state.value!));
-    } else if (state is RecordState) {
-      Map<String, Space> fields = {};
-      for (int index = 0; index < state.positionalFields.length; index++) {
-        fields['\$${index + 1}'] =
-            convertConstantValueToSpace(cache, state.positionalFields[index]);
-      }
-      for (MapEntry<String, DartObjectImpl> entry
-          in state.namedFields.entries) {
-        fields[entry.key] = convertConstantValueToSpace(cache, entry.value);
-      }
-      return Space(cache.getStaticType(constantValue.type), fields);
+    AnalyzerExhaustivenessCache cache, DartObjectImpl constantValue) {
+  InstanceState state = constantValue.state;
+  if (constantValue.isNull) {
+    return Space.nullSpace;
+  } else if (state is BoolState && state.value != null) {
+    return Space(cache.getBoolValueStaticType(state.value!));
+  } else if (state is RecordState) {
+    Map<String, Space> fields = {};
+    for (int index = 0; index < state.positionalFields.length; index++) {
+      fields['\$${index + 1}'] =
+          convertConstantValueToSpace(cache, state.positionalFields[index]);
     }
-    DartType type = constantValue.type;
-    if (type is InterfaceType && type.element.kind == ElementKind.ENUM) {
-      return Space(cache.getEnumElementStaticType(
-          type.element as EnumElement, constantValue));
+    for (MapEntry<String, DartObjectImpl> entry in state.namedFields.entries) {
+      fields[entry.key] = convertConstantValueToSpace(cache, entry.value);
     }
-    return Space(cache.getUniqueStaticType(
-        type, constantValue, constantValue.toString()));
+    return Space(cache.getStaticType(constantValue.type), fields);
   }
-  // TODO(johnniwinther): Assert that constant value is available when the
-  // exhaustiveness checking is complete.
-  return Space(cache.getUnknownStaticType());
+  DartType type = constantValue.type;
+  if (type is InterfaceType && type.element.kind == ElementKind.ENUM) {
+    return Space(cache.getEnumElementStaticType(
+        type.element as EnumElement, constantValue));
+  }
+  return Space(
+      cache.getUniqueStaticType(type, constantValue, constantValue.toString()));
 }
 
 Space convertPatternToSpace(
@@ -150,10 +144,32 @@ Space convertPatternToSpace(
   } else if (pattern is ParenthesizedPattern) {
     return convertPatternToSpace(cache, pattern.pattern, constantPatternValues,
         nonNull: nonNull);
+  } else if (pattern is NullAssertPattern ||
+      pattern is CastPattern ||
+      pattern is RelationalPattern ||
+      pattern is LogicalAndPattern) {
+    // These pattern do not add to the exhaustiveness coverage.
+    // TODO(johnniwinther): Handle `Null` aspect implicitly covered by
+    // [NullAssertPattern] and `as Null`.
+    // TODO(johnniwinther): Handle top in [AndPattern] branches.
+    return Space(cache.getUnknownStaticType());
+  } else if (pattern is ListPattern || pattern is MapPattern) {
+    // TODO(johnniwinther): Support list and map patterns. This not only
+    //  requires a new interpretation of [Space] fields that handles the
+    //  relation between concrete lengths, rest patterns with/without
+    //  subpattern, and list/map of arbitrary size and content, but also for the
+    //  runtime to check for lengths < 0.
+    return Space(cache.getUnknownStaticType());
+  } else if (pattern is ConstantPattern) {
+    DartObjectImpl? value = constantPatternValues[pattern];
+    if (value != null) {
+      return convertConstantValueToSpace(cache, value);
+    }
+    assert(false, "No constant value for $pattern");
+    return Space(cache.getUnknownStaticType());
   }
-  // TODO(johnniwinther): Handle remaining patterns.
-  DartObjectImpl? value = constantPatternValues[pattern];
-  return convertConstantValueToSpace(cache, value);
+  assert(false, "Unexpected pattern $pattern (${pattern.runtimeType})");
+  return Space(cache.getUnknownStaticType());
 }
 
 class AnalyzerEnumOperations

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

@@ -456,9 +456,25 @@ Space convertPatternToSpace(CfeExhaustivenessCache cache, Pattern pattern,
   } else if (pattern is NullCheckPattern) {
     return convertPatternToSpace(cache, pattern.pattern, constants, context,
         nonNull: true);
+  } else if (pattern is NullAssertPattern ||
+      pattern is CastPattern ||
+      pattern is InvalidPattern ||
+      pattern is RelationalPattern ||
+      pattern is AndPattern) {
+    // These pattern do not add to the exhaustiveness coverage.
+    // TODO(johnniwinther): Handle `Null` aspect implicitly covered by
+    // [NullAssertPattern] and `as Null`.
+    // TODO(johnniwinther): Handle top in [AndPattern] branches.
+    return new Space(cache.getUnknownStaticType());
+  } else if (pattern is ListPattern || pattern is MapPattern) {
+    // TODO(johnniwinther): Support list and map patterns. This not only
+    //  requires a new interpretation of [Space] fields that handles the
+    //  relation between concrete lengths, rest patterns with/without
+    //  subpattern, and list/map of arbitrary size and content, but also for the
+    //  runtime to check for lengths < 0.
+    return new Space(cache.getUnknownStaticType());
   }
-
-  // TODO(johnniwinther): Handle remaining constants.
+  assert(false, "Unexpected pattern $pattern (${pattern.runtimeType}).");
   return new Space(cache.getUnknownStaticType());
 }
 

pkg/front_end/test/spell_checking_list_code.txt

@@ -748,6 +748,7 @@ intermediate
 internet
 interop
 interpolations
+interpretation
 interrupted
 intersections
 intersects
@@ -822,6 +823,7 @@ leeway
 left's
 legitimately
 len
+lengths
 lets
 letting
 levels