Merge pull request #3416 from delsner/bugfix/#3388-fix-template-funct…

…ion-return-type

#3388 Bugfix for cpp template function return types

MERGING without getting a review from @pragmaware.

Units/parser-cxx.r/template-nested-triangle-brackets.d/input-2.hpp

@@ -16,7 +16,7 @@ template<typename T,int I,int J = I < V> K funcC(T t)
 }
 
 // The original comment: This stuff is allowed by C++03
-//    template<typename T,int I,int J = (I >> 2)> K funcD(T t)
+//    template<typename T,int I,int J = I >> 2> K funcD(T t)
 // However, the above input is rejected with:
 //    error: default template arguments may not be used in function templates
 //           without `-std=c++11' or `-std=gnu++11'

Units/parser-cxx.r/templates7.d/args.ctags

@@ -0,0 +1,3 @@
+--sort=no
+--kinds-C++=*
+--fields-c++=+{template}

Units/parser-cxx.r/templates7.d/expected.tags

@@ -0,0 +1,8 @@
+foo	input.hpp	/^A foo()$/;"	f	typeref:typename:A	template:<typename A,typename B>
+A	input.hpp	/^template<typename A, typename B>$/;"	Z	function:foo	typeref:meta:typename
+B	input.hpp	/^template<typename A, typename B>$/;"	Z	function:foo	typeref:meta:typename
+bar	input.hpp	/^A& bar(A& a, const B& b)$/;"	f	typeref:typename:A &	template:<typename A,typename B>
+A	input.hpp	/^template<typename A, typename B>$/;"	Z	function:bar	typeref:meta:typename
+B	input.hpp	/^template<typename A, typename B>$/;"	Z	function:bar	typeref:meta:typename
+a	input.hpp	/^A& bar(A& a, const B& b)$/;"	z	function:bar	typeref:typename:A &	file:
+b	input.hpp	/^A& bar(A& a, const B& b)$/;"	z	function:bar	typeref:typename:const B &	file:

Units/parser-cxx.r/templates7.d/input.hpp

@@ -0,0 +1,11 @@
+template<typename A, typename B>
+A foo()
+{
+    return A();
+}
+
+template<typename A, typename B>
+A& bar(A& a, const B& b)
+{
+    return a;
+}

Units/parser-cxx.r/templates7.d/validator

@@ -0,0 +1 @@
+cxx11

parsers/cxx/cxx_parser_template.c

@@ -269,7 +269,10 @@ cxxParserParseTemplateAngleBracketsInternal(bool bCaptureTypeParameters,int iNes
 	// around but without proper state (include headers, macro expansion, full type
 	// database etc) we simply can't do the same. However, we try to recover if we
 	// figure out we (or the programmer?) screwed up.
-	//
+	// For 'greater-than' operators, the first non-nested operator is taken as the
+	// end of the template parameter list rather than a 'greater-than' operator.
+	// Treating non-nested operators differently is a syntax error at least since C++03
+	// onwards according to https://en.cppreference.com/w/cpp/language/template_parameters.
 	//
 	// Like gcc, if this function knows identifiers in a template prefix more,
 	// the quality of parsing becomes better.
@@ -421,35 +424,8 @@ cxxParserParseTemplateAngleBracketsInternal(bool bCaptureTypeParameters,int iNes
 
 				CXX_DEBUG_PRINT("Found %d greater-than signs",iGreaterThanCount);
 
-				// check greater than operator: very narrow conditions
-				if(
-					(iGreaterThanCount == 1) &&
-					(
-						// whatever op 2 [C++03 allows this without parens]
-						// whatever op (...) [C++03 allows this without parens]
-						cxxTokenTypeIsOneOf(
-								g_cxx.pToken,
-								CXXTokenTypeNumber | CXXTokenTypeOpeningParenthesis
-							) ||
-						// whatever op nonTypeParameter [C++03 allows this without parens]
-						(
-							cxxTokenTypeIs(g_cxx.pToken,CXXTokenTypeIdentifier) &&
-							cxxTokenIsPresentInTemplateParametersAsNonType(g_cxx.pToken)
-						)
-						// WARNING: don't be tempted to add a loose condition that has
-						// (!cxxTokenIsPresentInTemplateParametersAsType()) on the right.
-						// It's unsafe.
-					)
-				)
-				{
-					CXX_DEBUG_PRINT("Treating as greater-than sign");
-
-					if(cxxTokenTypeIsOneOf(g_cxx.pToken,CXXTokenTypeOpeningParenthesis))
-						cxxParserUngetCurrentToken(); // needs to be condensed
-
-					continue;
-				}
-
+				// We do not check for the greater than operator, as it is only valid
+				// inside parentheses in a template parameter list (see i#3388).
 
 				// check right shift operator: a bit broader conditions
 				if(