From 979734578a6c2a11dce55c3c583c051b13b45ffc Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Tue, 8 Sep 2015 15:33:47 -0400
Subject: [PATCH] re PR c++/67041 ([C++14] Variable template initialized by
 call to lambda does not compile)

	PR c++/67041
	* pt.c (tsubst_copy_and_build): Handle variables like functions.

From-SVN: r227553
---
 gcc/cp/ChangeLog                              |  5 +++++
 gcc/cp/pt.c                                   | 19 +++++++++++--------
 .../g++.dg/cpp1y/lambda-var-templ1.C          | 11 +++++++++++
 3 files changed, 27 insertions(+), 8 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp1y/lambda-var-templ1.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 6115fd19f03..3a412aeef36 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,8 @@
+2015-09-08  Jason Merrill  <jason@redhat.com>
+
+	PR c++/67041
+	* pt.c (tsubst_copy_and_build): Handle variables like functions.
+
 2015-09-08  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/67369
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 2544751cb42..05e6d83a396 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -16321,15 +16321,14 @@ tsubst_copy_and_build (tree t,
 	LAMBDA_EXPR_MUTABLE_P (r) = LAMBDA_EXPR_MUTABLE_P (t);
 	LAMBDA_EXPR_DISCRIMINATOR (r)
 	  = (LAMBDA_EXPR_DISCRIMINATOR (t));
-	/* For a function scope, we want to use tsubst so that we don't
-	   complain about referring to an auto function before its return
-	   type has been deduced.  Otherwise, we want to use tsubst_copy so
-	   that we look up the existing field/parameter/variable rather
-	   than build a new one.  */
 	tree scope = LAMBDA_EXPR_EXTRA_SCOPE (t);
-	if (scope && TREE_CODE (scope) == FUNCTION_DECL)
+	if (!scope)
+	  /* No substitution needed.  */;
+	else if (VAR_OR_FUNCTION_DECL_P (scope))
+	  /* For a function or variable scope, we want to use tsubst so that we
+	     don't complain about referring to an auto before deduction.  */
 	  scope = tsubst (scope, args, complain, in_decl);
-	else if (scope && TREE_CODE (scope) == PARM_DECL)
+	else if (TREE_CODE (scope) == PARM_DECL)
 	  {
 	    /* Look up the parameter we want directly, as tsubst_copy
 	       doesn't do what we need.  */
@@ -16342,8 +16341,12 @@ tsubst_copy_and_build (tree t,
 	    if (DECL_CONTEXT (scope) == NULL_TREE)
 	      DECL_CONTEXT (scope) = fn;
 	  }
-	else
+	else if (TREE_CODE (scope) == FIELD_DECL)
+	  /* For a field, use tsubst_copy so that we look up the existing field
+	     rather than build a new one.  */
 	  scope = RECUR (scope);
+	else
+	  gcc_unreachable ();
 	LAMBDA_EXPR_EXTRA_SCOPE (r) = scope;
 	LAMBDA_EXPR_RETURN_TYPE (r)
 	  = tsubst (LAMBDA_EXPR_RETURN_TYPE (t), args, complain, in_decl);
diff --git a/gcc/testsuite/g++.dg/cpp1y/lambda-var-templ1.C b/gcc/testsuite/g++.dg/cpp1y/lambda-var-templ1.C
new file mode 100644
index 00000000000..4c2a3cb3e60
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/lambda-var-templ1.C
@@ -0,0 +1,11 @@
+// PR c++/67041
+// { dg-do compile { target c++14 } }
+
+template<typename T>
+auto test = [](){
+    return T{};
+};
+
+int main() {
+    test<int>();
+}
-- 
2.30.2