Create separate scopes for constructors, setters, and other members.

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

Index: pkg/front_end/lib/src/fasta/kernel/kernel_library_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/kernel_library_builder.dart b/pkg/front_end/lib/src/fasta/kernel/kernel_library_builder.dart
index d7598fd056935e29db2a8ea7d4acfe8a774c18ce..45b17e597b90736e39df436e4336873dd2b672b3 100644
--- a/pkg/front_end/lib/src/fasta/kernel/kernel_library_builder.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/kernel_library_builder.dart
@@ -46,10 +46,10 @@ import 'kernel_builder.dart'
         KernelTypeVariableBuilder,
         MemberBuilder,
         MetadataBuilder,
-        MixedAccessor,
         NamedMixinApplicationBuilder,
         PrefixBuilder,
         ProcedureBuilder,
+        Scope,
         TypeBuilder,
         TypeVariableBuilder,
         compareProcedures;
@@ -103,6 +103,17 @@ class KernelLibraryBuilder
       int charOffset) {
     assert(currentDeclaration.parent == libraryDeclaration);
     Map<String, MemberBuilder> members = currentDeclaration.members;
+    Map<String, MemberBuilder> constructors = currentDeclaration.constructors;
+    Map<String, MemberBuilder> setters = currentDeclaration.setters;
+
+    Scope classScope = new Scope(
+        members, setters, scope.withTypeVariables(typeVariables),
+        isModifiable: false);
+
+    // When looking up a constructor, we don't consider type variables or the
+    // library scope.
+    Scope constructorScope =
+        new Scope(constructors, null, null, isModifiable: false);
     ClassBuilder cls = new SourceClassBuilder(
         metadata,
         modifiers,
@@ -110,17 +121,22 @@ class KernelLibraryBuilder
         typeVariables,
         supertype,
         interfaces,
-        members,
+        classScope,
+        constructorScope,
         this,
         new List<ConstructorReferenceBuilder>.from(constructorReferences),
         charOffset);
     constructorReferences.clear();
-    members.forEach((String name, MemberBuilder builder) {
-      while (builder != null) {
-        builder.parent = cls;
-        builder = builder.next;
+    void setParent(String name, MemberBuilder member) {
+      while (member != null) {
+        member.parent = cls;
+        member = member.next;
       }
-    });
+    }
+
+    members.forEach(setParent);
+    constructors.forEach(setParent);
+    setters.forEach(setParent);
     // Nested declaration began in `OutlineBuilder.beginClassDeclaration`.
     endNestedDeclaration().resolveTypes(typeVariables, this);
     addBuilder(className, cls, charOffset);
@@ -151,10 +167,28 @@ class KernelLibraryBuilder
         charOffset);
   }
 
-  String computeConstructorName(String name) {
-    assert(isConstructorName(name, currentDeclaration.name));
+  String computeAndValidateConstructorName(String name, int charOffset) {
+    String className = currentDeclaration.name;
+    bool startsWithClassName = name.startsWith(className);
+    if (startsWithClassName && name.length == className.length) {
+      // Unnamed constructor or factory.
+      return "";
+    }
     int index = name.indexOf(".");
-    return index == -1 ? "" : name.substring(index + 1);
+    if (startsWithClassName && index == className.length) {
+      // Named constructor or factory.
+      return name.substring(index + 1);
+    }
+    if (index == -1) {
+      // A legal name for a regular method, but not for a constructor.
+      return null;
+    }
+    String suffix = name.substring(index + 1);
+    addCompileTimeError(
+        charOffset,
+        "'$name' isn't a legal method name.\n"
+        "Did you mean '$className.$suffix'?");
+    return suffix;
   }
 
   void addProcedure(
@@ -175,8 +209,10 @@ class KernelLibraryBuilder
     // `OutlineBuilder.beginTopLevelMethod`.
     endNestedDeclaration().resolveTypes(typeVariables, this);
     ProcedureBuilder procedure;
-    if (!isTopLevel && isConstructorName(name, currentDeclaration.name)) {
-      name = computeConstructorName(name);
+    String constructorName =
+        isTopLevel ? null : computeAndValidateConstructorName(name, charOffset);
+    if (constructorName != null) {
+      name = constructorName;
       procedure = new KernelConstructorBuilder(
           metadata,
           modifiers & ~abstractMask,
@@ -214,7 +250,7 @@ class KernelLibraryBuilder
   void addFactoryMethod(
       List<MetadataBuilder> metadata,
       int modifiers,
-      ConstructorReferenceBuilder constructorName,
+      ConstructorReferenceBuilder constructorNameReference,
       List<FormalParameterBuilder> formals,
       AsyncMarker asyncModifier,
       ConstructorReferenceBuilder redirectionTarget,
@@ -225,11 +261,13 @@ class KernelLibraryBuilder
     // Nested declaration began in `OutlineBuilder.beginFactoryMethod`.
     DeclarationBuilder<KernelTypeBuilder> factoryDeclaration =
         endNestedDeclaration();
-    String name = constructorName.name;
-    if (isConstructorName(name, currentDeclaration.name)) {
-      name = computeConstructorName(name);
+    String name = constructorNameReference.name;
+    String constructorName =
+        computeAndValidateConstructorName(name, charOffset);
+    if (constructorName != null) {
+      name = constructorName;
     }
-    assert(constructorName.suffix == null);
+    assert(constructorNameReference.suffix == null);
     KernelProcedureBuilder procedure = new KernelProcedureBuilder(
         metadata,
         staticMask | modifiers,
@@ -335,6 +373,7 @@ class KernelLibraryBuilder
   Builder buildAmbiguousBuilder(
       String name, Builder builder, Builder other, int charOffset,
       {bool isExport: false, bool isImport: false}) {
+    // TODO(ahe): Can I move this to Scope or Prefix?
     if (builder == other) return builder;
     if (builder is InvalidTypeBuilder) return builder;
     if (other is InvalidTypeBuilder) return other;
@@ -352,7 +391,7 @@ class KernelLibraryBuilder
     Uri otherUri;
     Uri preferredUri;
     Uri hiddenUri;
-    if (members[name] == builder) {
+    if (scope.local[name] == builder) {
       isLocal = true;
       preferred = builder;
       hiddenUri = other.computeLibraryUri();
@@ -394,26 +433,15 @@ class KernelLibraryBuilder
       return preferred;
     }
     if (builder.next == null && other.next == null) {
-      if (builder.isGetter && other.isSetter) {
-        return new MixedAccessor(builder, other, this);
-      } else if (builder.isSetter && other.isGetter) {
-        return new MixedAccessor(other, builder, this);
-      }
       if (isImport && builder is PrefixBuilder && other is PrefixBuilder) {
         // Handles the case where the same prefix is used for different
         // imports.
-        PrefixBuilder prefix = builder;
-        other.exports.forEach((String name, Builder member) {
-          Builder existing = exports[name];
-          if (existing != null) {
-            if (existing != member) {
-              member = buildAmbiguousBuilder(name, existing, member, charOffset,
-                  isExport: isExport, isImport: isImport);
-            }
-          }
-          prefix.exports[name] = member;
-        });
-        return builder;
+        return builder
+          ..exports.merge(other.exports,
+              (String name, Builder existing, Builder member) {
+            return buildAmbiguousBuilder(name, existing, member, charOffset,
+                isExport: isExport, isImport: isImport);
+          });
       }
     }
     if (isExport) {
@@ -515,11 +543,3 @@ class KernelLibraryBuilder
     assert(mixinApplicationClasses.isEmpty);
   }
 }
-
-bool isConstructorName(String name, String className) {
-  if (name.startsWith(className)) {
-    if (name.length == className.length) return true;
-    if (name.startsWith(".", className.length)) return true;
-  }
-  return false;
-}