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 b1fdf5ce787..47f4a66ef6a 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
@@ -4112,7 +4112,7 @@ public class AST2TemplateTests extends AST2CPPTestBase {
 	public void testTypedefPreservation_380498c() throws Exception {
 		BindingAssertionHelper ba= getAssertionHelper();
 		ICPPVariable s = ba.assertNonProblem("s :", "s", ICPPVariable.class);
-		assertTrue(s.getType() instanceof ITypedef);
+		assertInstance(s.getType(), ITypedef.class);
 		assertEquals("string", ASTTypeUtil.getType(s.getType(), false));
 	}
 
diff --git a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/internal/index/tests/IndexCPPTemplateResolutionTest.java b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/internal/index/tests/IndexCPPTemplateResolutionTest.java
index d0026141c17..70289ca4118 100644
--- a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/internal/index/tests/IndexCPPTemplateResolutionTest.java
+++ b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/internal/index/tests/IndexCPPTemplateResolutionTest.java
@@ -98,7 +98,7 @@ public class IndexCPPTemplateResolutionTest extends IndexBindingResolutionTestBa
 	}
 
 	public IndexCPPTemplateResolutionTest() {
-		setStrategy(new ReferencedProject(true));
+		setStrategy(new SinglePDOMTestStrategy(true));
 	}
 
     // template<typename _TpAllocator>
@@ -3089,6 +3089,55 @@ public class IndexCPPTemplateResolutionTest extends IndexBindingResolutionTestBa
 	public void testRegression_402498() throws Exception {
 		checkBindings();
 	}
+
+	//	template <typename Iterator>
+	//	struct iterator_traits {
+	//	    typedef typename Iterator::value_type value_type;
+	//	};
+	//
+	//	template <typename I>
+	//	struct normal;
+	//
+	//	template <typename T>
+	//	struct normal<T*> {
+	//	    typedef T value_type;
+	//	};
 	
-	
+	//	template <class Iterator>
+	//	struct iterator_value {
+	//	    typedef typename iterator_traits<Iterator>::value_type type;
+	//	};
+	//
+	//	template <typename BidiIter, typename RegexTraits = typename iterator_value<BidiIter>::type>
+	//	struct regex_compiler;
+	//
+	//	typedef normal<char*> Iter;
+	//
+	//	typedef regex_compiler<Iter> sregex_compiler;
+	//
+	//	template<typename Char>
+	//	struct xpression_linker;
+	//
+	//	template<typename BidiIter>
+	//	struct matchable_ex {
+	//	    typedef BidiIter iterator_type;
+	//	    typedef typename iterator_value<iterator_type>::type char_type;
+	//
+	//	    void link(xpression_linker<char_type>);
+	//	};
+	//
+	//	template<typename BidiIter>
+	//	struct sub_match {
+	//	    typedef typename iterator_value<BidiIter>::type value_type;
+	//	    operator value_type() const;
+	//	};
+	//
+	//	void waldo(char);
+	//	        
+	//	void foo(sub_match<Iter> w) {
+	//	    waldo(w);
+	//	}
+	public void testRegression_516338() throws Exception {
+		checkBindings();
+	}
 }
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/CPPTemplates.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/CPPTemplates.java
index da964ef2b0d..75a83d7d672 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/CPPTemplates.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/CPPTemplates.java
@@ -1450,9 +1450,37 @@ public class CPPTemplates {
 			return new CPPTemplateNonTypeArgument(newEval, context.getPoint());
 		}
 
-		final IType orig= arg.getTypeValue();
-		final IType inst= instantiateType(orig, context);
-		if (orig == inst)
+		// Which to instantiate, getOriginalTypeValue() or getTypeValue()?
+		//
+		// Using getOriginalTypeValue() is better for typedef preservation,
+		// and in the case of alias template instances, also necessary for 
+		// correctness (since an alias template instance could have dependent 
+		// arguments that don't appear in the resulting type, and these 
+		// arguments could SFINAE out during instantiation; the popular 
+		// "void_t" technique relies on this).
+		//
+		// However, caching of template instances is based on the normalized
+		// representation of arguments, which uses getTypeValue(). This,
+		// together with certain deficiencies in ASTTypeUtil (namely, that
+		// template parameters owned by different templates end up with the
+		// same string representation), leads to tricky bugs if we try to
+		// use getOriginalTypeValue() here all the time (observe, e.g., how
+		// IndexCPPTemplateResolutionTest.testRegression_516338 fails if we
+		// unconditionally use getOriginalTypeValue() here).
+		//
+		// As a compromise, we use getOriginalTypeValue() in the case where
+		// it's important for correctness (alias template instances), and
+		// getTypeValue() otherwise.
+		IType type;
+		final IType origType = arg.getOriginalTypeValue();
+		if (origType instanceof ICPPAliasTemplateInstance) {
+			type = origType;
+		} else {
+			type = arg.getTypeValue();
+		}
+		
+		final IType inst= instantiateType(type, context);
+		if (type == inst)
 			return arg;
 		return new CPPTemplateTypeArgument(inst);
 	}
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/SemanticUtil.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/SemanticUtil.java
index e689d1cc156..15f78fb1fdf 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/SemanticUtil.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/SemanticUtil.java
@@ -438,7 +438,8 @@ public class SemanticUtil {
 		if (!(typedefType instanceof ITypedef))
 			return null;
 		IType nestedType = type;
-		while (!nestedType.isSameType(((ITypedef) typedefType).getType())) {
+		IType typedefTarget = ((ITypedef) typedefType).getType();
+		while (!nestedType.isSameType(typedefTarget)) {
 			if (nestedType instanceof IQualifierType) {
 				nestedType = ((IQualifierType) nestedType).getType();
 			} else if (nestedType instanceof IPointerType) {
@@ -448,7 +449,9 @@ public class SemanticUtil {
 			} else if (nestedType instanceof ICPPReferenceType) {
 				nestedType = ((ICPPReferenceType) nestedType).getType();
 			} else {
-				return null;
+				// The typedef's target could itself be a (pointer or reference
+				// to, or qualified version of) a typedef. Try substituting that too.
+				return substituteTypedef(type, typedefTarget);
 			}
 		}