Introduce getPrefixEndToken to avoid too big context in messages.

pkg/compiler/lib/src/tree/nodes.dart

Index: pkg/compiler/lib/src/tree/nodes.dart
diff --git a/pkg/compiler/lib/src/tree/nodes.dart b/pkg/compiler/lib/src/tree/nodes.dart
index 04d46f54c28a4c8ac003abe471bc0673d9572a1b..ce0e355d8e32f1fcf2e95e37e2a059d46c62beed 100644
--- a/pkg/compiler/lib/src/tree/nodes.dart
+++ b/pkg/compiler/lib/src/tree/nodes.dart
@@ -147,6 +147,12 @@ abstract class Node extends NullTreeElementMixin implements Spannable {
 
   Token getBeginToken();
 
+  /// Returns the token that ends the 'prefix' of this node.
+  ///
+  /// For instance the end of the parameters in a [FunctionExpression] or the
+  /// start of a class body for a [ClassNode].

[ahe, 2016/02/04 11:32:33]

The last token *before* the start of a class body?

[Johnni Winther, 2016/02/05 09:14:20]

Done.

+  Token getPrefixEndToken() => getEndToken();
+
   Token getEndToken();
 
   Assert asAssert() => null;
@@ -263,6 +269,11 @@ class ClassNode extends Node {
 
   Token getBeginToken() => beginToken;
 
+  @override
+  Token getPrefixEndToken() {
+    return body != null ? body.getBeginToken() : getEndToken();

[ahe, 2016/02/04 11:32:33]

How about using the token before body.getBeginToken()?

[Johnni Winther, 2016/02/05 09:14:20]

Done.

+  }
+
   Token getEndToken() => endToken;
 }
 
@@ -738,6 +749,10 @@ class FunctionDeclaration extends Statement {
   visitChildren(Visitor visitor) => function.accept(visitor);
 
   Token getBeginToken() => function.getBeginToken();
+
+  @override
+  Token getPrefixEndToken() => function.getPrefixEndToken();
+
   Token getEndToken() => function.getEndToken();
 }
 
@@ -826,6 +841,11 @@ class FunctionExpression extends Expression with StoredTreeElementMixin {
     return firstBeginToken(name, parameters);
   }
 
+  @override
+  Token getPrefixEndToken() {
+    return parameters != null ? parameters.getEndToken() : name.getEndToken();
+  }
+
   Token getEndToken() {
     Token token = (body == null) ? null : body.getEndToken();
     token = (token == null) ? parameters.getEndToken() : token;