diff --git a/src/main/java/com/mojang/brigadier/arguments/CommandArgumentType.java b/src/main/java/com/mojang/brigadier/arguments/CommandArgumentType.java
index f968a74..61be7ba 100644
--- a/src/main/java/com/mojang/brigadier/arguments/CommandArgumentType.java
+++ b/src/main/java/com/mojang/brigadier/arguments/CommandArgumentType.java
@@ -6,7 +6,7 @@ import com.mojang.brigadier.exceptions.CommandException;
 import java.util.Set;
 
 public interface CommandArgumentType<T> {
-    ParsedArgument<T> parse(String command) throws CommandException;
+    <S> ParsedArgument<S, T> parse(String command) throws CommandException;
 
     void listSuggestions(String command, Set<String> output);
 }
diff --git a/src/main/java/com/mojang/brigadier/arguments/IntegerArgumentType.java b/src/main/java/com/mojang/brigadier/arguments/IntegerArgumentType.java
index 3e56f74..684b43d 100644
--- a/src/main/java/com/mojang/brigadier/arguments/IntegerArgumentType.java
+++ b/src/main/java/com/mojang/brigadier/arguments/IntegerArgumentType.java
@@ -42,7 +42,7 @@ public class IntegerArgumentType implements CommandArgumentType<Integer> {
     }
 
     @Override
-    public ParsedArgument<Integer> parse(String command) throws CommandException {
+    public <S> ParsedArgument<S, Integer> parse(String command) throws CommandException {
         String raw = SPLITTER.split(command).iterator().next();
 
         try {
diff --git a/src/main/java/com/mojang/brigadier/arguments/StringArgumentType.java b/src/main/java/com/mojang/brigadier/arguments/StringArgumentType.java
index bb170d8..7aee66c 100644
--- a/src/main/java/com/mojang/brigadier/arguments/StringArgumentType.java
+++ b/src/main/java/com/mojang/brigadier/arguments/StringArgumentType.java
@@ -39,7 +39,7 @@ public class StringArgumentType implements CommandArgumentType<String> {
     }
 
     @Override
-    public ParsedArgument<String> parse(String command) throws CommandException {
+    public <S> ParsedArgument<S, String> parse(String command) throws CommandException {
         if (type == StringType.GREEDY_PHRASE) {
             return new FixedParsedArgument<>(command, command);
         } else if (type == StringType.SINGLE_WORLD) {
diff --git a/src/main/java/com/mojang/brigadier/context/CommandContext.java b/src/main/java/com/mojang/brigadier/context/CommandContext.java
index ef472d5..d6ab34f 100644
--- a/src/main/java/com/mojang/brigadier/context/CommandContext.java
+++ b/src/main/java/com/mojang/brigadier/context/CommandContext.java
@@ -5,17 +5,18 @@ import com.google.common.collect.Maps;
 import com.google.common.primitives.Primitives;
 import com.mojang.brigadier.Command;
 import com.mojang.brigadier.tree.CommandNode;
+import sun.security.x509.OIDMap;
 
 import java.util.Map;
 
 public class CommandContext<S> {
     private final S source;
-    private final Map<String, ParsedArgument<?>> arguments;
+    private final Map<String, ParsedArgument<S, ?>> arguments;
     private final Command<S> command;
     private final Map<CommandNode<S>, String> nodes;
     private final String input;
 
-    public CommandContext(S source, Map<String, ParsedArgument<?>> arguments, Command<S> command, Map<CommandNode<S>, String> nodes, String input) {
+    public CommandContext(S source, Map<String, ParsedArgument<S, ?>> arguments, Command<S> command, Map<CommandNode<S>, String> nodes, String input) {
         this.source = source;
         this.arguments = arguments;
         this.command = command;
@@ -33,16 +34,17 @@ public class CommandContext<S> {
 
     @SuppressWarnings("unchecked")
     public <V> V getArgument(String name, Class<V> clazz) {
-        ParsedArgument<?> argument = arguments.get(name);
+        ParsedArgument<S, ?> argument = arguments.get(name);
 
         if (argument == null) {
             throw new IllegalArgumentException("No such argument '" + name + "' exists on this command");
         }
 
-        if (Primitives.wrap(clazz).isAssignableFrom(argument.getResult().getClass())) {
-            return ((ParsedArgument<V>) argument).getResult();
+        final Object result = argument.getResult(source);
+        if (Primitives.wrap(clazz).isAssignableFrom(result.getClass())) {
+            return (V) result;
         } else {
-            throw new IllegalArgumentException("Argument '" + name + "' is defined as " + argument.getResult().getClass().getSimpleName() + ", not " + clazz);
+            throw new IllegalArgumentException("Argument '" + name + "' is defined as " + result.getClass().getSimpleName() + ", not " + clazz);
         }
     }
 
@@ -79,7 +81,7 @@ public class CommandContext<S> {
     }
 
     public CommandContext<S> copy() {
-        Map<String, ParsedArgument<?>> arguments = Maps.newLinkedHashMap();
+        Map<String, ParsedArgument<S, ?>> arguments = Maps.newLinkedHashMap();
         this.arguments.forEach((k, v) -> arguments.put(k, v.copy()));
         return new CommandContext<>(source, arguments, command, nodes, input);
     }
diff --git a/src/main/java/com/mojang/brigadier/context/CommandContextBuilder.java b/src/main/java/com/mojang/brigadier/context/CommandContextBuilder.java
index 962332a..44828ff 100644
--- a/src/main/java/com/mojang/brigadier/context/CommandContextBuilder.java
+++ b/src/main/java/com/mojang/brigadier/context/CommandContextBuilder.java
@@ -8,7 +8,7 @@ import com.mojang.brigadier.tree.CommandNode;
 import java.util.Map;
 
 public class CommandContextBuilder<S> {
-    private final Map<String, ParsedArgument<?>> arguments = Maps.newHashMap();
+    private final Map<String, ParsedArgument<S, ?>> arguments = Maps.newHashMap();
     private final Map<CommandNode<S>, String> nodes = Maps.newLinkedHashMap();
     private final StringBuilder input = new StringBuilder();
     private S source;
@@ -27,12 +27,12 @@ public class CommandContextBuilder<S> {
         return source;
     }
 
-    public CommandContextBuilder<S> withArgument(String name, ParsedArgument<?> argument) {
+    public CommandContextBuilder<S> withArgument(String name, ParsedArgument<S, ?> argument) {
         this.arguments.put(name, argument);
         return this;
     }
 
-    public Map<String, ParsedArgument<?>> getArguments() {
+    public Map<String, ParsedArgument<S, ?>> getArguments() {
         return arguments;
     }
 
diff --git a/src/main/java/com/mojang/brigadier/context/DynamicParsedArgument.java b/src/main/java/com/mojang/brigadier/context/DynamicParsedArgument.java
index 4edb165..4eb8beb 100644
--- a/src/main/java/com/mojang/brigadier/context/DynamicParsedArgument.java
+++ b/src/main/java/com/mojang/brigadier/context/DynamicParsedArgument.java
@@ -1,14 +1,14 @@
 package com.mojang.brigadier.context;
 
-import java.util.function.Supplier;
+import java.util.function.Function;
 
-public class DynamicParsedArgument<T> implements ParsedArgument<T> {
+public class DynamicParsedArgument<S, T> implements ParsedArgument<S, T> {
     private final String raw;
-    private Supplier<T> supplier;
+    private Function<S, T> supplier;
     private boolean evaluated;
     private T result;
 
-    public DynamicParsedArgument(String raw, Supplier<T> supplier) {
+    public DynamicParsedArgument(String raw, Function<S, T> supplier) {
         this.raw = raw;
         this.supplier = supplier;
     }
@@ -19,9 +19,9 @@ public class DynamicParsedArgument<T> implements ParsedArgument<T> {
     }
 
     @Override
-    public T getResult() {
+    public T getResult(S source) {
         if (!evaluated) {
-            result = supplier.get();
+            result = supplier.apply(source);
             evaluated = true;
         }
         return result;
@@ -48,7 +48,7 @@ public class DynamicParsedArgument<T> implements ParsedArgument<T> {
     }
 
     @Override
-    public ParsedArgument<T> copy() {
+    public ParsedArgument<S, T> copy() {
         return new DynamicParsedArgument<>(raw, supplier);
     }
 }
diff --git a/src/main/java/com/mojang/brigadier/context/FixedParsedArgument.java b/src/main/java/com/mojang/brigadier/context/FixedParsedArgument.java
index 4d54931..da19481 100644
--- a/src/main/java/com/mojang/brigadier/context/FixedParsedArgument.java
+++ b/src/main/java/com/mojang/brigadier/context/FixedParsedArgument.java
@@ -1,6 +1,6 @@
 package com.mojang.brigadier.context;
 
-public class FixedParsedArgument<T> implements ParsedArgument<T> {
+public class FixedParsedArgument<S, T> implements ParsedArgument<S, T> {
     private final String raw;
     private final T result;
 
@@ -15,7 +15,7 @@ public class FixedParsedArgument<T> implements ParsedArgument<T> {
     }
 
     @Override
-    public T getResult() {
+    public T getResult(S source) {
         return result;
     }
 
@@ -40,7 +40,7 @@ public class FixedParsedArgument<T> implements ParsedArgument<T> {
     }
 
     @Override
-    public ParsedArgument<T> copy() {
+    public ParsedArgument<S, T> copy() {
         return new FixedParsedArgument<>(raw, result);
     }
 }
diff --git a/src/main/java/com/mojang/brigadier/context/ParsedArgument.java b/src/main/java/com/mojang/brigadier/context/ParsedArgument.java
index 578888b..846be5c 100644
--- a/src/main/java/com/mojang/brigadier/context/ParsedArgument.java
+++ b/src/main/java/com/mojang/brigadier/context/ParsedArgument.java
@@ -1,9 +1,9 @@
 package com.mojang.brigadier.context;
 
-public interface ParsedArgument<T> {
+public interface ParsedArgument<S, T> {
     String getRaw();
 
-    T getResult();
+    T getResult(S source);
 
-    ParsedArgument<T> copy();
+    ParsedArgument<S, T> copy();
 }
diff --git a/src/main/java/com/mojang/brigadier/tree/ArgumentCommandNode.java b/src/main/java/com/mojang/brigadier/tree/ArgumentCommandNode.java
index b6bfb2d..ce1ab63 100644
--- a/src/main/java/com/mojang/brigadier/tree/ArgumentCommandNode.java
+++ b/src/main/java/com/mojang/brigadier/tree/ArgumentCommandNode.java
@@ -2,7 +2,6 @@ package com.mojang.brigadier.tree;
 
 import com.mojang.brigadier.Command;
 import com.mojang.brigadier.arguments.CommandArgumentType;
-import com.mojang.brigadier.builder.ArgumentBuilder;
 import com.mojang.brigadier.builder.RequiredArgumentBuilder;
 import com.mojang.brigadier.context.CommandContextBuilder;
 import com.mojang.brigadier.context.ParsedArgument;
@@ -44,7 +43,7 @@ public class ArgumentCommandNode<S, T> extends CommandNode<S> {
 
     @Override
     public String parse(String command, CommandContextBuilder<S> contextBuilder) throws CommandException {
-        ParsedArgument<T> parsed = type.parse(command);
+        ParsedArgument<S, T> parsed = type.parse(command);
         int start = parsed.getRaw().length();
 
         contextBuilder.withArgument(name, parsed);
diff --git a/src/test/java/com/mojang/brigadier/arguments/IntegerArgumentTypeTest.java b/src/test/java/com/mojang/brigadier/arguments/IntegerArgumentTypeTest.java
index 699fbd6..a84baf5 100644
--- a/src/test/java/com/mojang/brigadier/arguments/IntegerArgumentTypeTest.java
+++ b/src/test/java/com/mojang/brigadier/arguments/IntegerArgumentTypeTest.java
@@ -7,11 +7,12 @@ import com.mojang.brigadier.context.CommandContext;
 import com.mojang.brigadier.context.CommandContextBuilder;
 import com.mojang.brigadier.context.ParsedArgument;
 import com.mojang.brigadier.exceptions.CommandException;
-import com.mojang.brigadier.exceptions.CommandExceptionType;
 import org.junit.Before;
 import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.runners.MockitoJUnitRunner;
 
-import java.util.Map;
 import java.util.Set;
 
 import static com.mojang.brigadier.arguments.IntegerArgumentType.integer;
@@ -21,8 +22,11 @@ import static org.hamcrest.Matchers.is;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.fail;
 
+@RunWith(MockitoJUnitRunner.class)
 public class IntegerArgumentTypeTest {
     private IntegerArgumentType type;
+    @Mock
+    private Object source;
 
     @Before
     public void setUp() throws Exception {
@@ -31,10 +35,10 @@ public class IntegerArgumentTypeTest {
 
     @Test
     public void testParse() throws Exception {
-        ParsedArgument<Integer> result = type.parse("50");
+        ParsedArgument<Object, Integer> result = type.parse("50");
 
         assertThat(result.getRaw(), is("50"));
-        assertThat(result.getResult(), is(50));
+        assertThat(result.getResult(source), is(50));
     }
 
     @Test
@@ -61,10 +65,10 @@ public class IntegerArgumentTypeTest {
 
     @Test
     public void testParseLowerLimit() throws Exception {
-        ParsedArgument<Integer> result = type.parse("-100");
+        ParsedArgument<Object, Integer> result = type.parse("-100");
 
         assertThat(result.getRaw(), is("-100"));
-        assertThat(result.getResult(), is(-100));
+        assertThat(result.getResult(source), is(-100));
     }
 
     @Test
@@ -80,10 +84,10 @@ public class IntegerArgumentTypeTest {
 
     @Test
     public void testParseHigherLimit() throws Exception {
-        ParsedArgument<Integer> result = type.parse("100");
+        ParsedArgument<Object, Integer> result = type.parse("100");
 
         assertThat(result.getRaw(), is("100"));
-        assertThat(result.getResult(), is(100));
+        assertThat(result.getResult(source), is(100));
     }
 
     @Test
diff --git a/src/test/java/com/mojang/brigadier/arguments/StringArgumentTypeTest.java b/src/test/java/com/mojang/brigadier/arguments/StringArgumentTypeTest.java
index 6bead93..a44a014 100644
--- a/src/test/java/com/mojang/brigadier/arguments/StringArgumentTypeTest.java
+++ b/src/test/java/com/mojang/brigadier/arguments/StringArgumentTypeTest.java
@@ -3,8 +3,10 @@ package com.mojang.brigadier.arguments;
 import com.google.common.collect.Sets;
 import com.mojang.brigadier.context.ParsedArgument;
 import com.mojang.brigadier.exceptions.CommandException;
-import com.sun.xml.internal.ws.api.ComponentEx;
 import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.runners.MockitoJUnitRunner;
 
 import java.util.Collections;
 import java.util.Set;
@@ -25,97 +27,100 @@ import static org.hamcrest.Matchers.is;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.fail;
 
+@RunWith(MockitoJUnitRunner.class)
 public class StringArgumentTypeTest {
     private StringArgumentType type;
+    @Mock
+    private Object source;
 
     @Test
     public void testParseWord() throws Exception {
         type = word();
-        ParsedArgument<String> result = type.parse("hello world");
+        ParsedArgument<Object, String> result = type.parse("hello world");
 
         assertThat(result.getRaw(), is("hello"));
-        assertThat(result.getResult(), is("hello"));
+        assertThat(result.getResult(source), is("hello"));
     }
 
     @Test
     public void testParseWord_empty() throws Exception {
         type = word();
-        ParsedArgument<String> result = type.parse("");
+        ParsedArgument<Object, String> result = type.parse("");
 
         assertThat(result.getRaw(), is(""));
-        assertThat(result.getResult(), is(""));
+        assertThat(result.getResult(source), is(""));
     }
 
     @Test
     public void testParseWord_simple() throws Exception {
         type = word();
-        ParsedArgument<String> result = type.parse("hello");
+        ParsedArgument<Object, String> result = type.parse("hello");
 
         assertThat(result.getRaw(), is("hello"));
-        assertThat(result.getResult(), is("hello"));
+        assertThat(result.getResult(source), is("hello"));
     }
 
     @Test
     public void testParseString() throws Exception {
         type = string();
-        ParsedArgument<String> result = type.parse("hello world");
+        ParsedArgument<Object, String> result = type.parse("hello world");
 
         assertThat(result.getRaw(), is("hello"));
-        assertThat(result.getResult(), is("hello"));
+        assertThat(result.getResult(source), is("hello"));
     }
 
     @Test
     public void testParseGreedyString() throws Exception {
         type = greedyString();
-        ParsedArgument<String> result = type.parse("hello world");
+        ParsedArgument<Object, String> result = type.parse("hello world");
 
         assertThat(result.getRaw(), is("hello world"));
-        assertThat(result.getResult(), is("hello world"));
+        assertThat(result.getResult(source), is("hello world"));
     }
 
     @Test
     public void testParse() throws Exception {
         type = string();
-        ParsedArgument<String> result = type.parse("hello");
+        ParsedArgument<Object, String> result = type.parse("hello");
 
         assertThat(result.getRaw(), is("hello"));
-        assertThat(result.getResult(), is("hello"));
+        assertThat(result.getResult(source), is("hello"));
     }
 
     @Test
     public void testParseWordQuoted() throws Exception {
         type = word();
-        ParsedArgument<String> result = type.parse("\"hello \\\" world\"");
+        ParsedArgument<Object, String> result = type.parse("\"hello \\\" world\"");
 
         assertThat(result.getRaw(), is("\"hello"));
-        assertThat(result.getResult(), is("\"hello"));
+        assertThat(result.getResult(source), is("\"hello"));
     }
 
     @Test
     public void testParseQuoted() throws Exception {
         type = string();
-        ParsedArgument<String> result = type.parse("\"hello \\\" world\"");
+        ParsedArgument<Object, String> result = type.parse("\"hello \\\" world\"");
 
         assertThat(result.getRaw(), is("\"hello \\\" world\""));
-        assertThat(result.getResult(), is("hello \" world"));
+        assertThat(result.getResult(source), is("hello \" world"));
     }
 
     @Test
     public void testParseQuotedWithRemaining() throws Exception {
         type = string();
-        ParsedArgument<String> result = type.parse("\"hello \\\" world\" with remaining");
+        ParsedArgument<Object, String> result = type.parse("\"hello \\\" world\" with remaining");
 
         assertThat(result.getRaw(), is("\"hello \\\" world\""));
-        assertThat(result.getResult(), is("hello \" world"));
+        assertThat(result.getResult(source), is("hello \" world"));
     }
 
     @Test
     public void testParseNotQuoted() throws Exception {
         type = string();
-        ParsedArgument<String> result = type.parse("hello world");
+        ParsedArgument<Object, String> result = type.parse("hello world");
 
         assertThat(result.getRaw(), is("hello"));
-        assertThat(result.getResult(), is("hello"));
+        assertThat(result.getResult(source), is("hello"));
     }
 
     @Test
@@ -133,10 +138,10 @@ public class StringArgumentTypeTest {
     @Test
     public void testParseQuote_earlyUnquoteWithRemaining() throws Exception {
         type = string();
-        ParsedArgument<String> result = type.parse("\"hello\" world");
+        ParsedArgument<Object, String> result = type.parse("\"hello\" world");
 
         assertThat(result.getRaw(), is("\"hello\""));
-        assertThat(result.getResult(), is("hello"));
+        assertThat(result.getResult(source), is("hello"));
     }
 
     @Test
@@ -154,10 +159,10 @@ public class StringArgumentTypeTest {
     @Test
     public void testParseQuote_lateQuoteWithRemaining() throws Exception {
         type = string();
-        ParsedArgument<String> result = type.parse("hello \"world\"");
+        ParsedArgument<Object, String> result = type.parse("hello \"world\"");
 
         assertThat(result.getRaw(), is("hello"));
-        assertThat(result.getResult(), is("hello"));
+        assertThat(result.getResult(source), is("hello"));
     }
 
     @Test
@@ -187,10 +192,10 @@ public class StringArgumentTypeTest {
     @Test
     public void testParseEmpty() throws Exception {
         type = string();
-        ParsedArgument<String> result = type.parse("");
+        ParsedArgument<Object, String> result = type.parse("");
 
         assertThat(result.getRaw(), is(""));
-        assertThat(result.getResult(), is(""));
+        assertThat(result.getResult(source), is(""));
     }
 
     @Test
diff --git a/src/test/java/com/mojang/brigadier/context/CommandContextTest.java b/src/test/java/com/mojang/brigadier/context/CommandContextTest.java
index fc802e3..4d511f9 100644
--- a/src/test/java/com/mojang/brigadier/context/CommandContextTest.java
+++ b/src/test/java/com/mojang/brigadier/context/CommandContextTest.java
@@ -9,6 +9,7 @@ import org.junit.runner.RunWith;
 import org.mockito.Mock;
 import org.mockito.runners.MockitoJUnitRunner;
 
+import java.util.function.Function;
 import java.util.function.Supplier;
 
 import static com.mojang.brigadier.arguments.IntegerArgumentType.integer;
@@ -84,13 +85,13 @@ public class CommandContextTest {
     public void testCopy() throws Exception {
         Object first = new Object();
         Object second = new Object();
-        @SuppressWarnings("unchecked") Supplier<Object> supplier = (Supplier<Object>) mock(Supplier.class);
+        @SuppressWarnings("unchecked") Function<Object, Object> supplier = (Function<Object, Object>) mock(Function.class);
 
-        when(supplier.get()).thenReturn(first);
+        when(supplier.apply(source)).thenReturn(first);
         CommandContext<Object> context = builder.withNode(literal("test").build(), "test").withArgument("test", new DynamicParsedArgument<>("test", supplier)).build();
         assertThat(context.getArgument("test", Object.class), is(first));
 
-        when(supplier.get()).thenReturn(second);
+        when(supplier.apply(source)).thenReturn(second);
         CommandContext<Object> copy = context.copy();
         assertThat(context, is(equalTo(copy)));
         assertThat(copy.getArgument("test", Object.class), is(second));
diff --git a/src/test/java/com/mojang/brigadier/context/DynamicParsedArgumentTest.java b/src/test/java/com/mojang/brigadier/context/DynamicParsedArgumentTest.java
index f7ce6f5..ccbcdc7 100644
--- a/src/test/java/com/mojang/brigadier/context/DynamicParsedArgumentTest.java
+++ b/src/test/java/com/mojang/brigadier/context/DynamicParsedArgumentTest.java
@@ -1,14 +1,13 @@
 package com.mojang.brigadier.context;
 
 import com.google.common.testing.EqualsTester;
-import org.hamcrest.Matchers;
-import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.mockito.Mock;
 import org.mockito.runners.MockitoJUnitRunner;
 
+import java.util.function.Function;
 import java.util.function.Supplier;
 
 import static org.hamcrest.Matchers.equalTo;
@@ -20,9 +19,11 @@ import static org.mockito.Mockito.when;
 
 @RunWith(MockitoJUnitRunner.class)
 public class DynamicParsedArgumentTest {
-    private DynamicParsedArgument<Object> subject;
+    private DynamicParsedArgument<Object, Object> subject;
     @Mock
-    private Supplier<Object> supplier;
+    private Function<Object, Object> supplier;
+    @Mock
+    private Object source;
 
     @Before
     public void setUp() throws Exception {
@@ -32,28 +33,28 @@ public class DynamicParsedArgumentTest {
     @Test
     public void suppliedOnce() throws Exception {
         Object result = new Object();
-        when(supplier.get()).thenReturn(result);
+        when(supplier.apply(source)).thenReturn(result);
 
-        assertThat("first evaluation", subject.getResult(), is(result));
-        assertThat("already evaluated", subject.getResult(), is(result));
+        assertThat("first evaluation", subject.getResult(source), is(result));
+        assertThat("already evaluated", subject.getResult(source), is(result));
 
-        verify(supplier, times(1)).get();
+        verify(supplier, times(1)).apply(source);
     }
 
     @Test
     public void copy() throws Exception {
         Object result = new Object();
-        when(supplier.get()).thenReturn(result);
-        assertThat(subject.getResult(), is(result));
+        when(supplier.apply(source)).thenReturn(result);
+        assertThat(subject.getResult(source), is(result));
 
         Object newResult = new Object();
-        when(supplier.get()).thenReturn(newResult);
-        ParsedArgument<Object> copy = subject.copy();
-        assertThat(copy.getResult(), is(newResult));
+        when(supplier.apply(source)).thenReturn(newResult);
+        ParsedArgument<Object, Object> copy = subject.copy();
+        assertThat(copy.getResult(source), is(newResult));
 
         assertThat(copy, is(equalTo(subject)));
 
-        verify(supplier, times(2)).get();
+        verify(supplier, times(2)).apply(source);
     }
 
     @Test
diff --git a/src/test/java/com/mojang/brigadier/context/FixedParsedArgumentTest.java b/src/test/java/com/mojang/brigadier/context/FixedParsedArgumentTest.java
index 502a6b8..3cc107d 100644
--- a/src/test/java/com/mojang/brigadier/context/FixedParsedArgumentTest.java
+++ b/src/test/java/com/mojang/brigadier/context/FixedParsedArgumentTest.java
@@ -21,7 +21,7 @@ public class FixedParsedArgumentTest {
 
     @Test
     public void copy() throws Exception {
-        final FixedParsedArgument<String> argument = new FixedParsedArgument<>("foo", "bar");
+        final FixedParsedArgument<Object, String> argument = new FixedParsedArgument<>("foo", "bar");
         assertThat(argument.copy(), is(equalTo(argument)));
     }
 }
\ No newline at end of file
diff --git a/src/test/java/com/mojang/brigadier/tree/ArgumentCommandNodeTest.java b/src/test/java/com/mojang/brigadier/tree/ArgumentCommandNodeTest.java
index 462e957..7c6776f 100644
--- a/src/test/java/com/mojang/brigadier/tree/ArgumentCommandNodeTest.java
+++ b/src/test/java/com/mojang/brigadier/tree/ArgumentCommandNodeTest.java
@@ -24,6 +24,7 @@ import static org.mockito.Mockito.mock;
 public class ArgumentCommandNodeTest extends AbstractCommandNodeTest {
     private ArgumentCommandNode<Object, Integer> node;
     private CommandContextBuilder<Object> contextBuilder;
+    private Object source = new Object();
 
     @Override
     protected CommandNode<Object> getCommandNode() {
@@ -41,7 +42,7 @@ public class ArgumentCommandNodeTest extends AbstractCommandNodeTest {
         assertThat(node.parse("123 456", contextBuilder), is(" 456"));
 
         assertThat(contextBuilder.getArguments().containsKey("foo"), is(true));
-        assertThat(contextBuilder.getArguments().get("foo").getResult(), is(123));
+        assertThat(contextBuilder.getArguments().get("foo").getResult(source), is(123));
     }
 
     @Test
@@ -49,7 +50,7 @@ public class ArgumentCommandNodeTest extends AbstractCommandNodeTest {
         assertThat(node.parse("123", contextBuilder), is(""));
 
         assertThat(contextBuilder.getArguments().containsKey("foo"), is(true));
-        assertThat(contextBuilder.getArguments().get("foo").getResult(), is(123));
+        assertThat(contextBuilder.getArguments().get("foo").getResult(source), is(123));
     }
 
     @Test