From d9c2afbec28068ba8716df7d403e2f753879ecb4 Mon Sep 17 00:00:00 2001
From: Markus Schorn <markus.schorn@windriver.com>
Date: Wed, 12 Nov 2008 10:01:07 +0000
Subject: [PATCH] Scalability of parsing nested template ids, bug 246079.

---
 .../parser/tests/ast2/AST2TemplateTests.java  | 35 +++++++++++++++++++
 .../dom/parser/cpp/GNUCPPSourceParser.java    | 33 +++++++++--------
 2 files changed, 53 insertions(+), 15 deletions(-)

diff --git a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2TemplateTests.java b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2TemplateTests.java
index b8bf471b44d..fba3c3ef9f8 100644
--- a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2TemplateTests.java
+++ b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2TemplateTests.java
@@ -3212,4 +3212,39 @@ public class AST2TemplateTests extends AST2BaseTest {
 		BindingAssertionHelper ba= new BindingAssertionHelper(getAboveComment(), true);
 		ba.assertNonProblem("x))", 1, ICPPVariable.class);
     }
+    
+    //    template<typename T, typename U> class TL {};
+    //    typedef int T;
+    //    typedef
+    //    TL<T, TL< T, TL< T, TL< T, TL<T,
+    //    TL<T, TL< T, TL< T, TL< T, TL<T,
+    //    TL<T, TL< T, TL< T, TL< T, TL<T,
+    //    TL<T, TL< T, TL< T, TL< T, TL<T,
+    //    TL<T, TL< T, TL< T, TL< T, TL<T,
+    //    T
+    //    > > > > >
+    //    > > > > >
+    //    > > > > >
+    //    > > > > >
+    //    > > > > >
+    //    type;
+    public void testNestedArguments_246079() throws Throwable {
+    	final Throwable[] th= {null};
+    	Thread t= new Thread(){
+    		@Override
+			public void run() {
+    			try {
+    				parseAndCheckBindings(getAboveComment(), ParserLanguage.CPP);
+    			} catch (Throwable e) {
+    				th[0]= e;
+    			}
+    		}
+    	};
+    	
+    	t.start();
+    	t.join(4000);
+    	assertFalse(t.isAlive());
+    	if (th[0] != null)
+    		throw th[0];
+    }
 }
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/GNUCPPSourceParser.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/GNUCPPSourceParser.java
index a17b614e5b3..6b83d220773 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/GNUCPPSourceParser.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/GNUCPPSourceParser.java
@@ -304,28 +304,31 @@ public class GNUCPPSourceParser extends AbstractGNUSourceCodeParser {
     		if(typeId != null && (LT(1)==IToken.tCOMMA || LT(1)==IToken.tGT || LT(1)==IToken.tEOC)) {
     			// potentially a type-id - check for id-expression ambiguity
     			IToken typeIdEnd= mark();
-
-    			backup(argStart);
     			try {
-    				IASTExpression expression = assignmentExpression();
-    				if(expression instanceof IASTIdExpression) {
-    					IASTIdExpression idExpression= (IASTIdExpression) expression;
-    					if(idExpression.getName() instanceof ICPPASTTemplateId) {
-    						/*
-    						 * A template-id cannot be used in an id-expression as a template argument.
-    						 * 
-    						 * 5.1-11 A template-id shall be used as an unqualified-id only as specified in
-    						 * 14.7.2, 14.7, and 14.5.4.
-    						 */
-    						throw backtrack;
-    					}
+    				// consider ambiguity with id-expressions, only:
+        			IASTDeclSpecifier declspec= typeId.getDeclSpecifier();
+        			if (!(declspec instanceof IASTNamedTypeSpecifier)) 
+        				throw backtrack;
+        			IASTName name= ((IASTNamedTypeSpecifier) declspec).getName();
+        			if (!name.contains(typeId)) 
+        				throw backtrack;
+        			
+        			// A template-id cannot be used in an id-expression as a template argument
+        			// 5.1-11 A template-id shall be used as an unqualified-id only as specified in
+        			// 14.7.2, 14.7, and 14.5.4.
+        			name= name.getLastName();
+        			if (name instanceof ICPPASTTemplateId)
+        				throw backtrack;
 
+        			backup(argStart);
+    				IASTExpression expression = assignmentExpression();
+    				if (expression instanceof IASTIdExpression) {
     					if (mark() != typeIdEnd) 
     						throw backtrack;
 
     					ICPPASTAmbiguousTemplateArgument ambiguity= createAmbiguousTemplateArgument();
     					ambiguity.addTypeId(typeId);
-    					ambiguity.addIdExpression(idExpression);
+    					ambiguity.addIdExpression((IASTIdExpression) expression);
     					list.add(ambiguity);
     				} else {
     					// prefer the typeId at this stage