[analyzer][cfe] Share the constraint collecting procedures

Part of #54902

Change-Id: I98dae68a61536cc3292f2a4f05cab22a8014486d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/392581
Reviewed-by: Paul Berry <paulberry@google.com>
Commit-Queue: Chloe Stefantsova <cstefantsova@google.com>

pkg/_fe_analyzer_shared/lib/src/type_inference/type_analyzer_operations.dart

@@ -906,6 +906,16 @@ abstract class TypeConstraintGenerator<
 
   TypeConstraintGenerator({required this.inferenceUsingBoundsIsEnabled});
 
+  /// Add constraint: [lower] <: [typeParameter] <: TOP.
+  void addLowerConstraintForParameter(
+      TypeParameterStructure typeParameter, TypeStructure lower,
+      {required AstNode? nodeForTesting});
+
+  /// Add constraint: BOTTOM <: [typeParameter] <: [upper].
+  void addUpperConstraintForParameter(
+      TypeParameterStructure typeParameter, TypeStructure upper,
+      {required AstNode? nodeForTesting});
+
   /// Returns the type arguments of the supertype of [type] that is an
   /// instantiation of [typeDeclaration]. If none of the supertypes of [type]
   /// are instantiations of [typeDeclaration], returns null.

pkg/_fe_analyzer_shared/test/type_inference/type_constraint_gatherer_test.dart

@@ -599,7 +599,7 @@ class _TypeConstraintGatherer extends TypeConstraintGenerator<Type,
         case var typeVar?
         when p.nullabilitySuffix == NullabilitySuffix.none &&
             _typeVariablesBeingConstrained.contains(typeVar)) {
-      _constraints.add('$typeVar <: $q');
+      addUpperConstraintForParameter(typeVar, q, nodeForTesting: null);
       return true;
     }
 
@@ -609,7 +609,7 @@ class _TypeConstraintGatherer extends TypeConstraintGenerator<Type,
         case var typeVar?
         when q.nullabilitySuffix == NullabilitySuffix.none &&
             _typeVariablesBeingConstrained.contains(typeVar)) {
-      _constraints.add('$p <: $typeVar');
+      addLowerConstraintForParameter(typeVar, p, nodeForTesting: null);
       return true;
     }
 
@@ -635,4 +635,16 @@ class _TypeConstraintGatherer extends TypeConstraintGenerator<Type,
   void restoreState(TypeConstraintGeneratorState state) {
     _constraints.length = state.count;
   }
+
+  @override
+  void addUpperConstraintForParameter(TypeParameter typeParameter, Type upper,
+      {required Node? nodeForTesting}) {
+    _constraints.add('$typeParameter <: $upper');
+  }
+
+  @override
+  void addLowerConstraintForParameter(TypeParameter typeParameter, Type lower,
+      {required Node? nodeForTesting}) {
+    _constraints.add('$lower <: $typeParameter');
+  }
 }

pkg/analyzer/lib/src/dart/element/type_constraint_gatherer.dart

@@ -71,6 +71,38 @@ class TypeConstraintGatherer extends shared.TypeConstraintGenerator<
   @override
   TypeSystemOperations get typeAnalyzerOperations => _typeSystemOperations;
 
+  @override
+  void addLowerConstraintForParameter(
+      TypeParameterElement element, DartType lower,
+      {required AstNode? nodeForTesting}) {
+    GeneratedTypeConstraint<DartType, TypeParameterElement, PromotableElement>
+        generatedTypeConstraint = GeneratedTypeConstraint<
+            DartType,
+            TypeParameterElement,
+            PromotableElement>.lower(element, SharedTypeSchemaView(lower));
+    _constraints.add(generatedTypeConstraint);
+    if (dataForTesting != null && nodeForTesting != null) {
+      (dataForTesting!.generatedTypeConstraints[nodeForTesting] ??= [])
+          .add(generatedTypeConstraint);
+    }
+  }
+
+  @override
+  void addUpperConstraintForParameter(
+      TypeParameterElement element, DartType upper,
+      {required AstNode? nodeForTesting}) {
+    GeneratedTypeConstraint<DartType, TypeParameterElement, PromotableElement>
+        generatedTypeConstraint = GeneratedTypeConstraint<
+            DartType,
+            TypeParameterElement,
+            PromotableElement>.upper(element, SharedTypeSchemaView(upper));
+    _constraints.add(generatedTypeConstraint);
+    if (dataForTesting != null && nodeForTesting != null) {
+      (dataForTesting!.generatedTypeConstraints[nodeForTesting] ??= [])
+          .add(generatedTypeConstraint);
+    }
+  }
+
   /// Returns the set of type constraints that was gathered.
   Map<
       TypeParameterElement,
@@ -148,7 +180,8 @@ class TypeConstraintGatherer extends shared.TypeConstraintGenerator<
         case var P_element?
         when P_nullability == NullabilitySuffix.none &&
             _typeParameters.contains(P_element)) {
-      _addUpper(P_element, Q, nodeForTesting: nodeForTesting);
+      addUpperConstraintForParameter(P_element, Q,
+          nodeForTesting: nodeForTesting);
       return true;
     }
 
@@ -165,7 +198,8 @@ class TypeConstraintGatherer extends shared.TypeConstraintGenerator<
                         P,
                         _typeSystemOperations.greatestClosureOfTypeInternal(
                             Q_element.bound!, [..._typeParameters]))))) {
-      _addLower(Q_element, P, nodeForTesting: nodeForTesting);
+      addLowerConstraintForParameter(Q_element, P,
+          nodeForTesting: nodeForTesting);
       return true;
     }
 
@@ -343,34 +377,6 @@ class TypeConstraintGatherer extends shared.TypeConstraintGenerator<
     return false;
   }
 
-  void _addLower(TypeParameterElement element, DartType lower,
-      {required AstNode? nodeForTesting}) {
-    GeneratedTypeConstraint<DartType, TypeParameterElement, PromotableElement>
-        generatedTypeConstraint = GeneratedTypeConstraint<
-            DartType,
-            TypeParameterElement,
-            PromotableElement>.lower(element, SharedTypeSchemaView(lower));
-    _constraints.add(generatedTypeConstraint);
-    if (dataForTesting != null && nodeForTesting != null) {
-      (dataForTesting!.generatedTypeConstraints[nodeForTesting] ??= [])
-          .add(generatedTypeConstraint);
-    }
-  }
-
-  void _addUpper(TypeParameterElement element, DartType upper,
-      {required AstNode? nodeForTesting}) {
-    GeneratedTypeConstraint<DartType, TypeParameterElement, PromotableElement>
-        generatedTypeConstraint = GeneratedTypeConstraint<
-            DartType,
-            TypeParameterElement,
-            PromotableElement>.upper(element, SharedTypeSchemaView(upper));
-    _constraints.add(generatedTypeConstraint);
-    if (dataForTesting != null && nodeForTesting != null) {
-      (dataForTesting!.generatedTypeConstraints[nodeForTesting] ??= [])
-          .add(generatedTypeConstraint);
-    }
-  }
-
   /// Matches [P] against [Q], where [P] and [Q] are both function types.
   ///
   /// If [P] is a subtype of [Q] under some constraints, the constraints making

pkg/front_end/lib/src/type_inference/type_constraint_gatherer.dart

@@ -135,31 +135,33 @@ class TypeConstraintGatherer extends shared.TypeConstraintGenerator<
         constrainSupertype: false, treeNodeForTesting: treeNodeForTesting);
   }
 
-  /// Add constraint: [lower] <: [parameter] <: TOP.
-  void _constrainParameterLower(StructuralParameter parameter, DartType lower,
-      {required TreeNode? treeNodeForTesting}) {
+  @override
+  void addLowerConstraintForParameter(
+      StructuralParameter parameter, DartType lower,
+      {required TreeNode? nodeForTesting}) {
     GeneratedTypeConstraint generatedTypeConstraint =
         new GeneratedTypeConstraint.lower(
             parameter, new SharedTypeSchemaView(lower));
-    if (treeNodeForTesting != null && _inferenceResultForTesting != null) {
+    if (nodeForTesting != null && _inferenceResultForTesting != null) {
       // Coverage-ignore-block(suite): Not run.
-      (_inferenceResultForTesting
-              .generatedTypeConstraints[treeNodeForTesting] ??= [])
+      (_inferenceResultForTesting.generatedTypeConstraints[nodeForTesting] ??=
+              [])
           .add(generatedTypeConstraint);
     }
     _protoConstraints.add(generatedTypeConstraint);
   }
 
-  /// Add constraint: BOTTOM <: [parameter] <: [upper].
-  void _constrainParameterUpper(StructuralParameter parameter, DartType upper,
-      {required TreeNode? treeNodeForTesting}) {
+  @override
+  void addUpperConstraintForParameter(
+      StructuralParameter parameter, DartType upper,
+      {required TreeNode? nodeForTesting}) {
     GeneratedTypeConstraint generatedTypeConstraint =
         new GeneratedTypeConstraint.upper(
             parameter, new SharedTypeSchemaView(upper));
-    if (treeNodeForTesting != null && _inferenceResultForTesting != null) {
+    if (nodeForTesting != null && _inferenceResultForTesting != null) {
       // Coverage-ignore-block(suite): Not run.
-      (_inferenceResultForTesting
-              .generatedTypeConstraints[treeNodeForTesting] ??= [])
+      (_inferenceResultForTesting.generatedTypeConstraints[nodeForTesting] ??=
+              [])
           .add(generatedTypeConstraint);
     }
     _protoConstraints.add(generatedTypeConstraint);
@@ -255,8 +257,8 @@ class TypeConstraintGatherer extends shared.TypeConstraintGenerator<
         case StructuralParameter pParameter?
         when pNullability == NullabilitySuffix.none &&
             _parametersToConstrain.contains(pParameter)) {
-      _constrainParameterUpper(pParameter, q,
-          treeNodeForTesting: treeNodeForTesting);
+      addUpperConstraintForParameter(pParameter, q,
+          nodeForTesting: treeNodeForTesting);
       return true;
     }
 
@@ -273,8 +275,8 @@ class TypeConstraintGatherer extends shared.TypeConstraintGenerator<
                     p,
                     typeOperations.greatestClosureOfTypeInternal(
                         qParameter.bound, _parametersToConstrain)))) {
-      _constrainParameterLower(qParameter, p,
-          treeNodeForTesting: treeNodeForTesting);
+      addLowerConstraintForParameter(qParameter, p,
+          nodeForTesting: treeNodeForTesting);
       return true;
     }
 
@@ -526,17 +528,17 @@ class TypeConstraintGatherer extends shared.TypeConstraintGenerator<
                               "Unsupported type '${type.runtimeType}'."));
           for (GeneratedTypeConstraint constraint in constraints) {
             if (constraint.isUpper) {
-              _constrainParameterUpper(
+              addUpperConstraintForParameter(
                   constraint.typeParameter,
                   eliminator.eliminateToLeast(
                       constraint.constraint.unwrapTypeSchemaView()),
-                  treeNodeForTesting: treeNodeForTesting);
+                  nodeForTesting: treeNodeForTesting);
             } else {
-              _constrainParameterLower(
+              addLowerConstraintForParameter(
                   constraint.typeParameter,
                   eliminator.eliminateToGreatest(
                       constraint.constraint.unwrapTypeSchemaView()),
-                  treeNodeForTesting: treeNodeForTesting);
+                  nodeForTesting: treeNodeForTesting);
             }
           }
           return true;