TypeChecker

- Moved the reference counting mechanism into the `TypeChecker` to avoid problem of seperate `DNodeGenerator` instances having their own seperate counts
- We now check the reference count values after function definition processing so as to get a proper count

Dependency

- Use the reference counting from `TypeChecker`
- Removed reference counting code

Test cases

- Added a positive case in the form of `unused_vars.t`
- Added a negative case in the form of `unused_vars_none.t`

source/tlang/compiler/typecheck/core.d

@@ -210,6 +210,23 @@ public final class TypeChecker
         }
 
         // NOTE: Check scope guard for "exit routines" which run here
+
+
+        /** 
+         * Find the variables which were declared but never used
+         *
+         * TODO: Add compiler entry check here for whether or not
+         * these should be printed out
+         */
+        Variable[] unusedVariables = getUnusedVariables();
+        gprintln("There are "~to!(string)(unusedVariables.length)~" unused variables");
+        if(unusedVariables.length)
+        {
+            foreach(Variable unusedVariable; unusedVariables)
+            {
+                gprintln("Variable '"~to!(string)(unusedVariable)~"' is declared but never");
+            }
+        }
     }
 
 
@@ -3258,6 +3275,51 @@ public final class TypeChecker
         //assert()
     }
 
+    /** 
+     * Maps a given `Variable` to its reference
+     * count. This includes the declaration
+     * thereof.
+     */
+    private uint[Variable] varRefCounts;
+
+    /** 
+     * Increments the given variable's reference
+     * count
+     *
+     * Params:
+     *   variable = the variable
+     */
+    void touch(Variable variable)
+    {
+        // Create entry if not existing yet
+        if(variable !in this.varRefCounts)
+        {
+            this.varRefCounts[variable] = 0;    
+        }
+
+        // Increment count
+        this.varRefCounts[variable]++;
+    }
+
+    /** 
+     * Returns all variables which were declared
+     * but not used
+     *
+     * Returns: the array of variables
+     */
+    public Variable[] getUnusedVariables()
+    {
+        Variable[] unused;
+        foreach(Variable variable; this.varRefCounts.keys())
+        {
+            if(!(this.varRefCounts[variable] > 1))
+            {
+                unused ~= variable;
+            }
+        }
+
+        return unused;
+    }
 }
 
 

source/tlang/compiler/typecheck/dependency/core.d

@@ -781,7 +781,7 @@ public class DNodeGenerator
                     Variable variable = cast(Variable)namedEntity;
 
                     /* Variable reference count must increase */
-                    touch(variable);
+                    tc.touch(variable);
 
                     /* Pool the node */
                     VariableNode varDecNode = poolT!(VariableNode, Variable)(variable);
@@ -1107,7 +1107,7 @@ public class DNodeGenerator
             writeln("VarType: "~to!(string)(variableType));
 
             /* Add an entry to the reference counting map */
-            touch(variable);
+            tc.touch(variable);
 
             /* Basic type */
             if(cast(Primitive)variableType)
@@ -1212,7 +1212,7 @@ public class DNodeGenerator
             assert(variable);
 
             /* Assinging to a variable is usage, therefore increment the reference count */
-            touch(variable);
+            tc.touch(variable);
 
 
             /* Pool the variable */
@@ -1708,52 +1708,4 @@ public class DNodeGenerator
 
         return classDNode;
     }
-
-
-    /** 
-     * Maps a given `Variable` to its reference
-     * count. This includes the declaration
-     * thereof.
-     */
-    private uint[Variable] varRefCounts;
-
-    /** 
-     * Increments the given variable's reference
-     * count
-     *
-     * Params:
-     *   variable = the variable
-     */
-    private void touch(Variable variable)
-    {
-        // Create entry if not existing yet
-        if(variable !in this.varRefCounts)
-        {
-            this.varRefCounts[variable] = 0;    
-        }
-
-        // Increment count
-        this.varRefCounts[variable]++;
-    }
-
-    /** 
-     * Returns all variables which were declared
-     * but not used
-     *
-     * Returns: the array of variables
-     */
-    public Variable[] getUnusedVariables()
-    {
-        Variable[] unused;
-        foreach(Variable variable; this.varRefCounts.keys())
-        {
-            if(!(this.varRefCounts[variable] > 1))
-            {
-                unused ~= variable;
-            }
-        }
-
-        return unused;
-    }
-
 }

source/tlang/testing/unused_vars.t

@@ -0,0 +1,3 @@
+module unused_vars;
+
+int j;

source/tlang/testing/unused_vars_none.t

@@ -0,0 +1,8 @@
+module unused_vars;
+
+int j;
+
+void thing()
+{
+    j = 1;
+}