Use GraphBuilder to construct an alias Graph

engine/runtime-compiler/src/main/java/org/enso/compiler/pass/analyse/alias/graph/GraphBuilder.java

@@ -0,0 +1,112 @@
+package org.enso.compiler.pass.analyse.alias.graph;
+
+/**
+ * Builder of {@link Graph}. Separates the concerns of building a graph of local symbol definitions
+ * and their usages from the actual querying of those symbols.
+ */
+public final class GraphBuilder {
+  private final Graph graph;
+  private final Graph.Scope scope;
+
+  private GraphBuilder(Graph graph, Graph.Scope scope) {
+    this.graph = graph;
+    this.scope = scope;
+  }
+
+  /**
+   * Creates new empty builder.
+   *
+   * @return empty builder
+   */
+  public static GraphBuilder create() {
+    var topLevel = Graph$.MODULE$.create();
+    return create(topLevel, topLevel.rootScope());
+  }
+
+  /**
+   * Creates a builder for given graph and scope.
+   *
+   * @param g the graph
+   * @param s its scope
+   * @return builder operating on the graph {@code g} starting at scope {@code s}
+   */
+  public static GraphBuilder create(Graph g, Graph.Scope s) {
+    return new GraphBuilder(g, s);
+  }
+
+  /**
+   * Creates a child scope and returns a builder for it.
+   *
+   * @return new builder for newly created scope, but the same graph
+   */
+  public GraphBuilder addChild() {
+    return new GraphBuilder(graph, scope.addChild());
+  }
+
+  /**
+   * Adds occurrence to current scope.
+   *
+   * @return this builder with modified scope
+   */
+  public GraphBuilder add(GraphOccurrence occ) {
+    this.scope.add(occ);
+    return this;
+  }
+
+  /**
+   * Adds definition to current scope.
+   *
+   * @return this builder with modified scope
+   */
+  public GraphBuilder addDefinition(GraphOccurrence.Def def) {
+    this.scope.addDefinition(def);
+    return this;
+  }
+
+  /**
+   * Finds definition ID of provided symbol.
+   *
+   * @param name the name of the symbol
+   * @return -1 if not such symbol found, otherwise ID of the symbol
+   */
+  public int findDef(String name) {
+    var first = this.scope.occurrences().values().find(occ -> occ.symbol().equals(name));
+    if (first.nonEmpty() && first.get() instanceof GraphOccurrence.Def def) {
+      return def.id();
+    } else {
+      return -1;
+    }
+  }
+
+  /** Creates new definition for */
+  public GraphOccurrence.Def newDef(
+      String symbol, java.util.UUID identifier, scala.Option<java.util.UUID> externalId) {
+    return newDef(symbol, identifier, externalId, false);
+  }
+
+  public GraphOccurrence.Def newDef(
+      String symbol,
+      java.util.UUID identifier,
+      scala.Option<java.util.UUID> externalId,
+      boolean suspended) {
+    return new GraphOccurrence.Def(graph.nextId(), symbol, identifier, externalId, suspended);
+  }
+
+  /** Factory method to create new [GraphOccurrence.Use]. */
+  public GraphOccurrence.Use newUse(
+      String symbol, java.util.UUID identifier, scala.Option<java.util.UUID> externalId) {
+    return new GraphOccurrence.Use(graph.nextId(), symbol, identifier, externalId);
+  }
+
+  public void resolveLocalUsage(GraphOccurrence.Use use) {
+    graph.resolveLocalUsage(use);
+  }
+
+  public Graph toGraph() {
+    return graph;
+  }
+
+  public Graph.Scope toScope() {
+    return scope;
+  }
+}

engine/runtime-compiler/src/main/scala/org/enso/compiler/context/LocalScope.scala

@@ -6,6 +6,7 @@ import org.enso.compiler.pass.analyse.FrameVariableNames
 import org.enso.compiler.pass.analyse.DataflowAnalysis
 import org.enso.compiler.pass.analyse.alias.graph.{
   GraphOccurrence,
+  GraphBuilder,
   Graph => AliasGraph
 }
 
@@ -92,7 +93,9 @@ class LocalScope(
     *
     * @return a child of this scope
     */
-  def createChild(): LocalScope = createChild(() => scope.addChild())
+  def createChild(): LocalScope = createChild(() => {
+    GraphBuilder.create(null, scope).addChild().toScope()
+  })
 
   /** Creates a child using a known aliasing scope.
     *