- Added context and scope management

1 files changed, 228 insertions, 0 deletions

diff --git a/sources/scalac/checkers/TreeChecker.java b/sources/scalac/checkers/TreeChecker.java
index 433d170c97..4f6e7c56e8 100644
--- a/sources/scalac/checkers/TreeChecker.java
+++ b/sources/scalac/checkers/TreeChecker.java
@@ -8,8 +8,15 @@
 
 package scalac.checkers;
 
+import java.util.HashSet;
+import java.util.Set;
+import java.util.Stack;
+
 import scalac.Unit;
+import scalac.ast.Tree;
 import scalac.symtab.Definitions;
+import scalac.symtab.Symbol;
+import scalac.util.Debug;
 
 /**
  * This checker checks that trees are well-formed. It checks both the
@@ -23,6 +30,30 @@ public class TreeChecker {
     /** The global definitions */
     private final Definitions definitions;
 
+    /** The stack of current units */
+    private final Stack/*<Unit>*/ units = new Stack();
+
+    /** The stack of current classes */
+    private final Stack/*<Symbol>*/ classes = new Stack();
+
+    /** The stack of current members */
+    private final Stack/*<Symbol>*/ members = new Stack();
+
+    /** The stack of current owners */
+    private final Stack/*<Symbol>*/ owners = new Stack();
+
+    /** The currently visible type variables */
+    private final Set/*<Symbol>*/ tvars = new HashSet();
+
+    /** The currently visible value variables */
+    private final Set/*<Symbol>*/ vvars = new HashSet();
+
+    /** The currently visible labels */
+    private final Set/*<Symbol>*/ labels = new HashSet();
+
+    /** The currently defined symbols */
+    private final Set/*<Symbol>*/ symbols = new HashSet();
+
     //########################################################################
     // Public Constructors
 
@@ -40,4 +71,201 @@ public class TreeChecker {
     }
 
     //########################################################################
+    // Private Methods - Declaring symbols
+
+    /** Do the trees contain the given symbols? */
+    private boolean containSymbols(Tree[] trees, Symbol[] symbols) {
+        if (trees.length != symbols.length) return false;
+        for (int i = 0; i < trees.length; i++)
+            if (trees[i].symbol() != symbols[i]) return false;
+        return true;
+    }
+
+    /** Remove parameters of symbol from current scope. */
+    private void scopeInsertParametersOf(Symbol symbol) {
+        Symbol[] tparams = symbol.typeParams();
+        for (int i = 0; i < tparams.length; i++)
+            scopeInsertTVariable(tparams[i], true);
+        Symbol[] vparams = symbol.valueParams();
+        for (int i = 0; i < vparams.length; i++)
+            scopeInsertVVariable(vparams[i], true);
+    }
+
+    /** Adds the type variable to the current scope. */
+    private void scopeInsertTVariable(Symbol symbol, boolean isParameter) {
+        assert !symbol.owner().isClass(): show(symbol);
+        assert symbol.isParameter() == isParameter: show(symbol);
+        registerSymbol(symbol);
+        tvars.add(symbol);
+    }
+
+    /** Adds the value variable to the current scope. */
+    private void scopeInsertVVariable(Symbol symbol, boolean isParameter) {
+        assert !symbol.owner().isClass(): show(symbol);
+        assert symbol.isParameter() == isParameter: show(symbol);
+        registerSymbol(symbol);
+        vvars.add(symbol);
+    }
+
+    /** Adds the label to current scope. */
+    private void scopeInsertLabel(Symbol symbol) {
+        assert !symbol.owner().isClass(): show(symbol);
+        registerSymbol(symbol);
+        labels.add(symbol);
+    }
+
+    /** Remove parameters of symbol from current scope. */
+    private void scopeRemoveParametersOf(Symbol symbol) {
+        Symbol[] tparams = symbol.typeParams();
+        for (int i = 0; i < tparams.length; i++)
+            scopeRemoveTVariable(tparams[i]);
+        Symbol[] vparams = symbol.valueParams();
+        for (int i = 0; i < vparams.length; i++)
+            scopeRemoveVVariable(vparams[i]);
+    }
+
+    /** Removes the type variable from current scope. */
+    private void scopeRemoveTVariable(Symbol symbol) {
+        boolean removed = tvars.remove(symbol);
+        assert removed: show(symbol);
+    }
+
+    /** Removes the value variable from current scope. */
+    private void scopeRemoveVVariable(Symbol symbol) {
+        boolean removed = vvars.remove(symbol);
+        assert removed: show(symbol);
+    }
+
+    /** Removes the label symbol from current scope. */
+    private void scopeRemoveLabel(Symbol symbol) {
+        boolean removed = labels.remove(symbol);
+        assert removed: show(symbol);
+    }
+
+    /** Registers the symbol. */
+    private void registerSymbol(Symbol symbol) {
+        boolean added = symbols.add(symbol);
+        assert added: show(symbol);
+    }
+
+    //########################################################################
+    // Private Methods - Managing current context
+
+    /** Returns the current unit. */
+    private Unit currentUnit() {
+        return units.size() > 0 ? (Unit)units.peek() : null;
+    }
+
+    /** Returns the current class. */
+    private Symbol currentClass() {
+        return classes.size() > 0 ? (Symbol)classes.peek() : null;
+    }
+
+    /** Returns the current member. */
+    private Symbol currentMember() {
+        return members.size() > 0 ? (Symbol)members.peek() : null;
+    }
+
+    /** Returns the current owner. */
+    private Symbol currentOwner() {
+        return owners.size() > 0 ? (Symbol)owners.peek() : null;
+    }
+
+    /** Sets the current unit to the given one. */
+    private void pushUnit(Unit unit) {
+        assert units.size() == 0: showPush(unit);
+        assert classes.size() == 0: showPush(unit);
+        assert members.size() == 0: showPush(unit);
+        units.push(unit);
+    }
+
+    /** Sets the current class to the given one. */
+    private void pushClass(Symbol clasz) {
+        assert clasz.isClass(): showPush(clasz);
+        assert members.size() == 0: showPush(clasz);
+        classes.push(clasz);
+        pushOwner(clasz);
+    }
+
+    /** Sets the current member to the given one. */
+    private void pushMember(Symbol member) {
+        assert member.isTerm(): showPush(member);
+        assert members.size() == 0: showPush(member);
+        assert member.owner() == currentClass(): showPush(member);
+        members.push(member);
+        pushOwner(member);
+    }
+
+    /** Sets the current owner to the given one. */
+    private void pushOwner(Symbol owner) {
+        owners.push(owner);
+    }
+
+    /** Sets the current unit to the previous one. */
+    private void popUnit() {
+        assert units.size() > 0: show();
+        units.pop();
+    }
+
+    /** Sets the current class to the previous one. */
+    private void popClass() {
+        assert members.size() == 0: show();
+        assert classes.size() > 0: show();
+        popOwner();
+        classes.pop();
+    }
+
+    /** Sets the current member to the previous one. */
+    private void popMember() {
+        assert members.size() > 0: show();
+        popOwner();
+        members.pop();
+    }
+
+    /** Sets the current owner to the previous one. */
+    private void popOwner() {
+        assert owners.size() > 0: show();
+        owners.pop();
+    }
+
+    //########################################################################
+    // Private Methods - Showing errors
+
+    /** Returns the current position. */
+    private String show() {
+        return
+            format("unit", currentUnit()) +
+            format("clasz", currentClass()) +
+            format("member", currentMember()) +
+            format("owner", currentOwner());
+    }
+
+    /** Returns the current position and given header and value. */
+    private String show(String header, Object value) {
+        return show() + format(header, value);
+    }
+
+    /** Returns the current position and given symbol. */
+    private String show(Symbol symbol) {
+        return show("symbol", symbol);
+    }
+
+    /** Returns the current position and given pushed value. */
+    private String showPush(Object value) {
+        return show("pushing", value);
+    }
+
+    /** Returns a string with the given header and value. */
+    private String format(String header, Object value) {
+        while (header.length() < 10) header = header + ' ';
+        return "\n" + header + ": " + toString(value);
+    }
+
+    /** Returns a string representation of the given value. */
+    private String toString(Object value) {
+        if (value instanceof Symbol) return Debug.show(value);
+        return String.valueOf(value);
+    }
+
+    //########################################################################
 }