diff --git a/gcc/testsuite/c-c++-common/cpp/va-opt-6.c b/gcc/testsuite/c-c++-common/cpp/va-opt-6.c
index 8a7761b39def..9a924318cb59 100644
--- a/gcc/testsuite/c-c++-common/cpp/va-opt-6.c
+++ b/gcc/testsuite/c-c++-common/cpp/va-opt-6.c
@@ -3,15 +3,15 @@
 /* { dg-options "-std=c++20" { target c++ } } */
 
 #define a ""
-#define b(...) a ## #__VA_OPT__(1)	/* { dg-error "pasting \"a\" and \"\"\"\" does not give a valid preprocessing token" } */
-#define c(...) a ## #__VA_OPT__(1)	/* { dg-error "pasting \"a\" and \"\"1\"\" does not give a valid preprocessing token" } */
+#define b(...) a ## #__VA_OPT__(1)	/* { dg-error "pasting 'a' and '\"\"' does not give a valid preprocessing token" } */
+#define c(...) a ## #__VA_OPT__(1)	/* { dg-error "pasting 'a' and '\"1\"' does not give a valid preprocessing token" } */
 #define d(...) #__VA_OPT__(1) ## !
 #define e(...) #__VA_OPT__(1) ## !
 #define f(...) #__VA_OPT__(. ## !)
 #define g(...) #__VA_OPT__(. ## !)
 b()
 c(1)
-d(   )		/* { dg-error "pasting \"\"\"\" and \"!\" does not give a valid preprocessing token" } */
-e(  1 )		/* { dg-error "pasting \"\"1\"\" and \"!\" does not give a valid preprocessing token" } */
+d(   )		/* { dg-error "pasting '\"\"' and '!' does not give a valid preprocessing token" } */
+e(  1 )		/* { dg-error "pasting '\"1\"' and '!' does not give a valid preprocessing token" } */
 f()
-g(0)		/* { dg-error "pasting \".\" and \"!\" does not give a valid preprocessing token" } */
+g(0)		/* { dg-error "pasting '.' and '!' does not give a valid preprocessing token" } */
diff --git a/gcc/testsuite/g++.dg/DRs/dr2579.C b/gcc/testsuite/g++.dg/DRs/dr2579.C
new file mode 100644
index 000000000000..dda3643826df
--- /dev/null
+++ b/gcc/testsuite/g++.dg/DRs/dr2579.C
@@ -0,0 +1,9 @@
+// DR 2579 - Undefined behavior when token pasting does not create a preprocessing token
+// { dg-do preprocess }
+// { dg-options "-pedantic-errors" }
+
+#define A(a, b) a ## b
+A(5,6)
+A(-,32)			// { dg-error "pasting '-' and '32' does not give a valid preprocessing token" }
+A("","")		// { dg-error "pasting '\"\"' and '\"\"' does not give a valid preprocessing token" }
+A(\,u0393)
diff --git a/gcc/testsuite/gcc.dg/c23-attr-syntax-6.c b/gcc/testsuite/gcc.dg/c23-attr-syntax-6.c
index f8c5b0facff9..4e6b80b76395 100644
--- a/gcc/testsuite/gcc.dg/c23-attr-syntax-6.c
+++ b/gcc/testsuite/gcc.dg/c23-attr-syntax-6.c
@@ -45,7 +45,7 @@ typedef int [[__extension__ __extension__]] b2; /* { dg-error {'extension' attri
 typedef int [[__extension__ unknown_attribute]] b3; /* { dg-error {'unknown_attribute' attribute ignored} } */
 typedef int [[__extension__ gnu:vector_size(4)]] b4; /* { dg-error {expected '\]' before ':'} } */
 /* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */
-typedef int [[__extension__ gnu JOIN2(:,:) vector_size (4)]] b5; /* { dg-error {pasting ":" and ":" does not give a valid preprocessing token} } */
+typedef int [[__extension__ gnu JOIN2(:,:) vector_size (4)]] b5; /* { dg-error {pasting ':' and ':' does not give a valid preprocessing token} } */
 /* { dg-error {expected '\]' before ':'} "" { target *-*-* } .-1 } */
 /* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-2 } */
 typedef int [[__extension__ gnu : : vector_size (4)]] b6; /* { dg-error {expected '\]' before ':'} } */
@@ -81,7 +81,7 @@ typedef int [[gnu :: vector_size (4)]] b18; /* { dg-error {attributes before C23
 typedef int [[gnu FOO vector_size (4)]] b19; /* { dg-error {attributes before C23} } */
 typedef int [[gnu :: vector_size (sizeof (void (*)(...)))]] b20; /* { dg-error {attributes before C23} } */
 /* { dg-error {requires a named argument before} "" { target *-*-* } .-1 } */
-typedef int [[gnu JOIN2(:,:) vector_size (4)]] b21; /* { dg-error {pasting ":" and ":" does not give a valid preprocessing token} } */
+typedef int [[gnu JOIN2(:,:) vector_size (4)]] b21; /* { dg-error {pasting ':' and ':' does not give a valid preprocessing token} } */
 /* { dg-error {expected '\]' before ':'} "" { target *-*-* } .-1 } */
 /* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-2 } */
 /* { dg-error {attributes before C23} "" { target *-*-* } .-3 } */
diff --git a/gcc/testsuite/gcc.dg/cpp/paste12-2.c b/gcc/testsuite/gcc.dg/cpp/paste12-2.c
index 6e2e4f1057d7..f46645a96136 100644
--- a/gcc/testsuite/gcc.dg/cpp/paste12-2.c
+++ b/gcc/testsuite/gcc.dg/cpp/paste12-2.c
@@ -6,6 +6,6 @@
 /* Test correct diagnostics when pasting in #include.
    Source: PR preprocessor/6780.  */
 
-#define inc2(a,b) <##a.b>  /* { dg-error "pasting \"<\" and \"stdio\" does not" } */
+#define inc2(a,b) <##a.b>  /* { dg-error "pasting '<' and 'stdio' does not" } */
 #define INC(X) inc2(X,h)
 #include INC(stdio)
diff --git a/gcc/testsuite/gcc.dg/cpp/paste12.c b/gcc/testsuite/gcc.dg/cpp/paste12.c
index 3e0f7b959222..f6b369695f80 100644
--- a/gcc/testsuite/gcc.dg/cpp/paste12.c
+++ b/gcc/testsuite/gcc.dg/cpp/paste12.c
@@ -8,4 +8,4 @@
 
 #define inc2(a,b) <##a.b>
 #define INC(X) inc2(X,h)
-#include INC(stdio) /* { dg-error "pasting \"<\" and \"stdio\" does not" } */
+#include INC(stdio) /* { dg-error "pasting '<' and 'stdio' does not" } */
diff --git a/gcc/testsuite/gcc.dg/cpp/paste14-2.c b/gcc/testsuite/gcc.dg/cpp/paste14-2.c
index 3b23ada3d215..bb5199949855 100644
--- a/gcc/testsuite/gcc.dg/cpp/paste14-2.c
+++ b/gcc/testsuite/gcc.dg/cpp/paste14-2.c
@@ -4,8 +4,8 @@
    { dg-do preprocess }
 */
 
-#define foo - ## >> /* { dg-error "pasting \"-\" and \">>\"" } */
+#define foo - ## >> /* { dg-error "pasting '-' and '>>'" } */
 foo
-#define bar = ## == /* { dg-error "pasting \"=\" and \"==\"" } */
+#define bar = ## == /* { dg-error "pasting '=' and '=='" } */
 bar
 
diff --git a/gcc/testsuite/gcc.dg/cpp/paste14.c b/gcc/testsuite/gcc.dg/cpp/paste14.c
index 043d5e5804ff..d60b3287bf00 100644
--- a/gcc/testsuite/gcc.dg/cpp/paste14.c
+++ b/gcc/testsuite/gcc.dg/cpp/paste14.c
@@ -5,6 +5,6 @@
 */
 
 #define foo - ## >>
-foo		/* { dg-error "pasting \"-\" and \">>\"" } */
+foo		/* { dg-error "pasting '-' and '>>'" } */
 #define bar = ## ==
-bar		/* { dg-error "pasting \"=\" and \"==\"" } */
+bar		/* { dg-error "pasting '=' and '=='" } */
diff --git a/libcpp/macro.cc b/libcpp/macro.cc
index d869b0239350..158c8215e522 100644
--- a/libcpp/macro.cc
+++ b/libcpp/macro.cc
@@ -1071,7 +1071,7 @@ paste_tokens (cpp_reader *pfile, location_t location,
       /* Mandatory error for all apart from assembler.  */
       if (CPP_OPTION (pfile, lang) != CLK_ASM)
 	cpp_error_with_line (pfile, CPP_DL_ERROR, location, 0,
-			     "pasting \"%.*s\" and \"%.*s\" does not give "
+			     "pasting %<%.*s%> and %<%.*s%> does not give "
 			     "a valid preprocessing token",
 			     (int) (lhsend - buf), buf,
 			     (int) (end - rhsstart), rhsstart);