Improve template error msg

compiler/src/dmd/funcsem.d

@@ -2068,16 +2068,48 @@ private void printCandidates(Decl)(Loc loc, Decl declaration, bool showDeprecate
     bool child; // true if inside an eponymous template
     const(char)* errorPrefix() @safe
     {
+        static char[128] buf;
+        size_t pos = 0;
         if (child)
             return "  - Containing: ";
 
-        // align with blank spaces after first message
-        enum plural = "Candidates are: ";
-        enum spaces = "                ";
         if (printed)
-            return spaces;
-
-        return (count == 1) ? "Candidate is: " : plural;
+        {
+            enum prefix = "Candidate "; // Prefix of the message to be displayed
+            foreach(i; 0 .. prefix.length)
+            {
+                buf[pos++] = prefix[i];
+            }
+            static char[64] tmp; // Buffer to store digits of the number
+            int idx = 0 ; // index for tmp buffer
+            int copy = printed + 1; // Stores the candidate number that will be displayed
+            // store the reversed number
+            while(copy)
+            {
+                tmp[idx++] = cast(char)('0' + copy%10);
+                copy /= 10;
+            }
+            tmp[idx] = '\0';
+            // in place reversal of digits
+            for(int end = idx-1 ; end>=0 ;end--)
+            {
+                buf[pos++] = tmp[end];
+            }
+            // Suffix of the message
+            enum suffix = " is: ";
+            foreach(i;0 .. suffix.length)
+            {
+                buf[pos++] = suffix[i];
+            }
+            buf[pos] = '\0';
+            return &buf[0];
+        }
+        if(count == 1)
+            return "Candidate is: ";
+        else
+        {
+            return "Candidate 1 is: ";
+        }
     }
     bool matchSymbol(Dsymbol s, bool print)
     {

compiler/test/fail_compilation/b19717a.d

@@ -4,8 +4,8 @@
 fail_compilation/b19717a.d(14): Error: forward reference to template `a`
 fail_compilation/b19717a.d(14): Error: forward reference to template `a`
 fail_compilation/b19717a.d(14): Error: none of the overloads of `a` are callable using argument types `()`
-fail_compilation/b19717a.d(13):        Candidates are: `b19717a.a(int b)`
-fail_compilation/b19717a.d(14):                        `b19717a.a(int b = a)`
+fail_compilation/b19717a.d(13):        Candidate 1 is: `b19717a.a(int b)`
+fail_compilation/b19717a.d(14):        Candidate 2 is: `b19717a.a(int b = a)`
 ---
 */
 module b19717a;

compiler/test/fail_compilation/constraints_func3.d

@@ -3,21 +3,21 @@ EXTRA_FILES: imports/constraints.d
 TEST_OUTPUT:
 ----
 fail_compilation/constraints_func3.d(53): Error: none of the overloads of template `imports.constraints.overload` are callable using argument types `!()(int)`
-fail_compilation/imports/constraints.d(39):        Candidates are: `overload(T)(T v)`
+fail_compilation/imports/constraints.d(39):        Candidate 1 is: `overload(T)(T v)`
   with `T = int`
   must satisfy the following constraint:
 `       N!T`
-fail_compilation/imports/constraints.d(40):                        `overload(T)(T v)`
+fail_compilation/imports/constraints.d(40):        Candidate 2 is: `overload(T)(T v)`
   with `T = int`
   must satisfy the following constraint:
 `       !P!T`
-fail_compilation/imports/constraints.d(41):                        `overload(T)(T v1, T v2)`
-fail_compilation/imports/constraints.d(42):                        `overload(T, V)(T v1, V v2)`
+fail_compilation/imports/constraints.d(41):        Candidate 3 is: `overload(T)(T v1, T v2)`
+fail_compilation/imports/constraints.d(42):        Candidate 4 is: `overload(T, V)(T v1, V v2)`
 fail_compilation/constraints_func3.d(54): Error: none of the overloads of template `imports.constraints.overload` are callable using argument types `!()(int, string)`
-fail_compilation/imports/constraints.d(39):        Candidates are: `overload(T)(T v)`
-fail_compilation/imports/constraints.d(40):                        `overload(T)(T v)`
-fail_compilation/imports/constraints.d(41):                        `overload(T)(T v1, T v2)`
-fail_compilation/imports/constraints.d(42):                        `overload(T, V)(T v1, V v2)`
+fail_compilation/imports/constraints.d(39):        Candidate 1 is: `overload(T)(T v)`
+fail_compilation/imports/constraints.d(40):        Candidate 2 is: `overload(T)(T v)`
+fail_compilation/imports/constraints.d(41):        Candidate 3 is: `overload(T)(T v1, T v2)`
+fail_compilation/imports/constraints.d(42):        Candidate 4 is: `overload(T, V)(T v1, V v2)`
   with `T = int,
        V = string`
   must satisfy one of the following constraints:

compiler/test/fail_compilation/constraints_func4.d

@@ -6,37 +6,37 @@ TEST_OUTPUT:
 fail_compilation/constraints_func4.d(90): Error: none of the overloads of template `imports.constraints.overload` are callable using argument types `!()(int)`
     overload(0);
             ^
-fail_compilation/imports/constraints.d(39):        Candidates are: `overload(T)(T v)`
+fail_compilation/imports/constraints.d(39):        Candidate 1 is: `overload(T)(T v)`
   with `T = int`
   must satisfy the following constraint:
 `       N!T`
 void overload(T)(T v) if (N!T);
      ^
-fail_compilation/imports/constraints.d(40):                        `overload(T)(T v)`
+fail_compilation/imports/constraints.d(40):        Candidate 2 is: `overload(T)(T v)`
   with `T = int`
   must satisfy the following constraint:
 `       !P!T`
 void overload(T)(T v) if (!P!T);
      ^
-fail_compilation/imports/constraints.d(41):                        `overload(T)(T v1, T v2)`
+fail_compilation/imports/constraints.d(41):        Candidate 3 is: `overload(T)(T v1, T v2)`
 void overload(T)(T v1, T v2) if (N!T);
      ^
-fail_compilation/imports/constraints.d(42):                        `overload(T, V)(T v1, V v2)`
+fail_compilation/imports/constraints.d(42):        Candidate 4 is: `overload(T, V)(T v1, V v2)`
 void overload(T, V)(T v1, V v2) if (N!T || N!V);
      ^
 fail_compilation/constraints_func4.d(91): Error: none of the overloads of template `imports.constraints.overload` are callable using argument types `!()(int, string)`
     overload(0, "");
             ^
-fail_compilation/imports/constraints.d(39):        Candidates are: `overload(T)(T v)`
+fail_compilation/imports/constraints.d(39):        Candidate 1 is: `overload(T)(T v)`
 void overload(T)(T v) if (N!T);
      ^
-fail_compilation/imports/constraints.d(40):                        `overload(T)(T v)`
+fail_compilation/imports/constraints.d(40):        Candidate 2 is: `overload(T)(T v)`
 void overload(T)(T v) if (!P!T);
      ^
-fail_compilation/imports/constraints.d(41):                        `overload(T)(T v1, T v2)`
+fail_compilation/imports/constraints.d(41):        Candidate 3 is: `overload(T)(T v1, T v2)`
 void overload(T)(T v1, T v2) if (N!T);
      ^
-fail_compilation/imports/constraints.d(42):                        `overload(T, V)(T v1, V v2)`
+fail_compilation/imports/constraints.d(42):        Candidate 4 is: `overload(T, V)(T v1, V v2)`
   with `T = int,
        V = string`
   must satisfy one of the following constraints:

compiler/test/fail_compilation/ctor_attr.d

@@ -2,12 +2,12 @@
 TEST_OUTPUT:
 ---
 fail_compilation/ctor_attr.d(26): Error: none of the overloads of `this` can construct a mutable object with argument types `(int)`
-fail_compilation/ctor_attr.d(16):        Candidates are: `ctor_attr.S.this(int x) const`
-fail_compilation/ctor_attr.d(18):                        `ctor_attr.S.this(string x)`
-fail_compilation/ctor_attr.d(17):                        `this()(int x) shared`
+fail_compilation/ctor_attr.d(16):        Candidate 1 is: `ctor_attr.S.this(int x) const`
+fail_compilation/ctor_attr.d(18):        Candidate 2 is: `ctor_attr.S.this(string x)`
+fail_compilation/ctor_attr.d(17):        Candidate 3 is: `this()(int x) shared`
 fail_compilation/ctor_attr.d(28): Error: none of the overloads of `foo` are callable using a mutable object with argument types `(int)`
-fail_compilation/ctor_attr.d(20):        Candidates are: `ctor_attr.S.foo(int x) immutable`
-fail_compilation/ctor_attr.d(21):                        `ctor_attr.S.foo(string x)`
+fail_compilation/ctor_attr.d(20):        Candidate 1 is: `ctor_attr.S.foo(int x) immutable`
+fail_compilation/ctor_attr.d(21):        Candidate 2 is: `ctor_attr.S.foo(string x)`
 ---
 */
 

compiler/test/fail_compilation/diag10415.d

@@ -2,8 +2,8 @@
 TEST_OUTPUT:
 ---
 fail_compilation/diag10415.d(36): Error: none of the overloads of `x` are callable using argument types `(int) const`
-fail_compilation/diag10415.d(13):        Candidates are: `diag10415.C.x() const`
-fail_compilation/diag10415.d(18):                        `diag10415.C.x(int __param_0)`
+fail_compilation/diag10415.d(13):        Candidate 1 is: `diag10415.C.x() const`
+fail_compilation/diag10415.d(18):        Candidate 2 is: `diag10415.C.x(int __param_0)`
 fail_compilation/diag10415.d(39): Error: d.x is not an lvalue
 ---
 */

compiler/test/fail_compilation/diag11078.d

@@ -2,8 +2,8 @@
 TEST_OUTPUT:
 ---
 fail_compilation/diag11078.d(19): Error: none of the overloads of `value` are callable using argument types `(double)`
-fail_compilation/diag11078.d(12):        Candidates are: `diag11078.S1.value()`
-fail_compilation/diag11078.d(13):                        `diag11078.S1.value(int n)`
+fail_compilation/diag11078.d(12):        Candidate 1 is: `diag11078.S1.value()`
+fail_compilation/diag11078.d(13):        Candidate 2 is: `diag11078.S1.value(int n)`
 ---
 */
 

compiler/test/fail_compilation/diag14818.d

@@ -2,8 +2,8 @@
 TEST_OUTPUT:
 ---
 fail_compilation/diag14818.d(40): Error: none of the overloads of `func` are callable using argument types `(string)`
-fail_compilation/diag14818.d(18):        Candidates are: `diag14818.foo(int __param_0)`
-fail_compilation/diag14818.d(19):                        `diag14818.bar(double __param_0)`
+fail_compilation/diag14818.d(18):        Candidate 1 is: `diag14818.foo(int __param_0)`
+fail_compilation/diag14818.d(19):        Candidate 2 is: `diag14818.bar(double __param_0)`
 fail_compilation/diag14818.d(41): Error: template instance `diag14818.X!string` does not match any template declaration
 fail_compilation/diag14818.d(41):        Candidates are:
 fail_compilation/diag14818.d(24):        Foo(T) if (is(T == int))

compiler/test/fail_compilation/diag8101.d

@@ -1,33 +1,33 @@
 /*
 TEST_OUTPUT:
 ---
-fail_compilation/diag8101.d(62): Error: function `f_0` is not callable using argument types `()`
-fail_compilation/diag8101.d(62):        too few arguments, expected 1, got 0
-fail_compilation/diag8101.d(34):        `diag8101.f_0(int)` declared here
-fail_compilation/diag8101.d(63): Error: none of the overloads of `f_1` are callable using argument types `()`
-fail_compilation/diag8101.d(36):        Candidates are: `diag8101.f_1(int)`
-fail_compilation/diag8101.d(37):                        `diag8101.f_1(int, int)`
-fail_compilation/diag8101.d(64): Error: none of the overloads of `f_2` are callable using argument types `()`
-fail_compilation/diag8101.d(39):        Candidates are: `diag8101.f_2(int)`
-fail_compilation/diag8101.d(40):                        `diag8101.f_2(int, int)`
-fail_compilation/diag8101.d(41):                        `diag8101.f_2(int, int, int)`
-fail_compilation/diag8101.d(42):                        `diag8101.f_2(int, int, int, int)`
-fail_compilation/diag8101.d(43):                        `diag8101.f_2(int, int, int, int, int)`
-fail_compilation/diag8101.d(44):                        `diag8101.f_2(int, int, int, int, int, int)`
-fail_compilation/diag8101.d(64):        ... (1 more, -v to show) ...
-fail_compilation/diag8101.d(66): Error: template `t_0` is not callable using argument types `!()()`
-fail_compilation/diag8101.d(47):        Candidate is: `t_0(T1)()`
-fail_compilation/diag8101.d(67): Error: none of the overloads of template `diag8101.t_1` are callable using argument types `!()()`
-fail_compilation/diag8101.d(49):        Candidates are: `t_1(T1)()`
-fail_compilation/diag8101.d(50):                        `t_1(T1, T2)()`
-fail_compilation/diag8101.d(68): Error: none of the overloads of template `diag8101.t_2` are callable using argument types `!()()`
-fail_compilation/diag8101.d(52):        Candidates are: `t_2(T1)()`
-fail_compilation/diag8101.d(53):                        `t_2(T1, T2)()`
-fail_compilation/diag8101.d(54):                        `t_2(T1, T2, T3)()`
-fail_compilation/diag8101.d(55):                        `t_2(T1, T2, T3, T4)()`
-fail_compilation/diag8101.d(56):                        `t_2(T1, T2, T3, T4, T5)()`
-fail_compilation/diag8101.d(57):                        `t_2(T1, T2, T3, T4, T5, T6)()`
-fail_compilation/diag8101.d(68):        ... (1 more, -v to show) ...
+fail_compilation\diag8101.d(62): Error: function `f_0` is not callable using argument types `()`
+fail_compilation\diag8101.d(62):        too few arguments, expected 1, got 0
+fail_compilation\diag8101.d(34):        `diag8101.f_0(int)` declared here
+fail_compilation\diag8101.d(63): Error: none of the overloads of `f_1` are callable using argument types `()`
+fail_compilation\diag8101.d(36):        Candidate 1 is: `diag8101.f_1(int)`
+fail_compilation\diag8101.d(37):        Candidate 2 is: `diag8101.f_1(int, int)`
+fail_compilation\diag8101.d(64): Error: none of the overloads of `f_2` are callable using argument types `()`
+fail_compilation\diag8101.d(39):        Candidate 1 is: `diag8101.f_2(int)`
+fail_compilation\diag8101.d(40):        Candidate 2 is: `diag8101.f_2(int, int)`
+fail_compilation\diag8101.d(41):        Candidate 3 is: `diag8101.f_2(int, int, int)`
+fail_compilation\diag8101.d(42):        Candidate 4 is: `diag8101.f_2(int, int, int, int)`
+fail_compilation\diag8101.d(43):        Candidate 5 is: `diag8101.f_2(int, int, int, int, int)`
+fail_compilation\diag8101.d(44):        Candidate 6 is: `diag8101.f_2(int, int, int, int, int, int)`
+fail_compilation\diag8101.d(64):        ... (1 more, -v to show) ...
+fail_compilation\diag8101.d(66): Error: template `t_0` is not callable using argument types `!()()`
+fail_compilation\diag8101.d(47):        Candidate is: `t_0(T1)()`
+fail_compilation\diag8101.d(67): Error: none of the overloads of template `diag8101.t_1` are callable using argument types `!()()`
+fail_compilation\diag8101.d(49):        Candidate 1 is: `t_1(T1)()`
+fail_compilation\diag8101.d(50):        Candidate 2 is: `t_1(T1, T2)()`
+fail_compilation\diag8101.d(68): Error: none of the overloads of template `diag8101.t_2` are callable using argument types `!()()`
+fail_compilation\diag8101.d(52):        Candidate 1 is: `t_2(T1)()`
+fail_compilation\diag8101.d(53):        Candidate 2 is: `t_2(T1, T2)()`
+fail_compilation\diag8101.d(54):        Candidate 3 is: `t_2(T1, T2, T3)()`
+fail_compilation\diag8101.d(55):        Candidate 4 is: `t_2(T1, T2, T3, T4)()`
+fail_compilation\diag8101.d(56):        Candidate 5 is: `t_2(T1, T2, T3, T4, T5)()`
+fail_compilation\diag8101.d(57):        Candidate 6 is: `t_2(T1, T2, T3, T4, T5, T6)()`
+fail_compilation\diag8101.d(68):        ... (1 more, -v to show) ...
 ---
 */
 

compiler/test/fail_compilation/diag8101b.d

@@ -1,16 +1,16 @@
 /*
 TEST_OUTPUT:
 ---
-fail_compilation/diag8101b.d(28): Error: none of the overloads of `foo` are callable using argument types `(double)`
-fail_compilation/diag8101b.d(19):        Candidates are: `diag8101b.S.foo(int __param_0)`
-fail_compilation/diag8101b.d(20):                        `diag8101b.S.foo(int __param_0, int __param_1)`
-fail_compilation/diag8101b.d(30): Error: function `diag8101b.S.bar(int __param_0)` is not callable using argument types `(double)`
-fail_compilation/diag8101b.d(30):        cannot pass argument `1.0` of type `double` to parameter `int __param_0`
-fail_compilation/diag8101b.d(33): Error: none of the overloads of `foo` are callable using a `const` object with argument types `(int)`
-fail_compilation/diag8101b.d(19):        Candidates are: `diag8101b.S.foo(int __param_0)`
-fail_compilation/diag8101b.d(20):                        `diag8101b.S.foo(int __param_0, int __param_1)`
-fail_compilation/diag8101b.d(35): Error: mutable method `diag8101b.S.bar` is not callable using a `const` object
-fail_compilation/diag8101b.d(22):        Consider adding `const` or `inout` here
+fail_compilation\diag8101b.d(28): Error: none of the overloads of `foo` are callable using argument types `(double)`
+fail_compilation\diag8101b.d(19):        Candidate 1 is: `diag8101b.S.foo(int __param_0)`
+fail_compilation\diag8101b.d(20):        Candidate 2 is: `diag8101b.S.foo(int __param_0, int __param_1)`
+fail_compilation\diag8101b.d(30): Error: function `diag8101b.S.bar(int __param_0)` is not callable using argument types `(double)`
+fail_compilation\diag8101b.d(30):        cannot pass argument `1.0` of type `double` to parameter `int __param_0`
+fail_compilation\diag8101b.d(33): Error: none of the overloads of `foo` are callable using a `const` object with argument types `(int)`
+fail_compilation\diag8101b.d(19):        Candidate 1 is: `diag8101b.S.foo(int __param_0)`
+fail_compilation\diag8101b.d(20):        Candidate 2 is: `diag8101b.S.foo(int __param_0, int __param_1)`
+fail_compilation\diag8101b.d(35): Error: mutable method `diag8101b.S.bar` is not callable using a `const` object
+fail_compilation\diag8101b.d(22):        Consider adding `const` or `inout` here
 ---
 */
 

compiler/test/fail_compilation/fail14997.d

@@ -4,8 +4,8 @@
 TEST_OUTPUT:
 ---
 fail_compilation/fail14997.d(19): Error: none of the overloads of `this` are callable using argument types `()`
-fail_compilation/fail14997.d(14):        Candidates are: `fail14997.Foo.this(int a)`
-fail_compilation/fail14997.d(15):                        `fail14997.Foo.this(string a)`
+fail_compilation/fail14997.d(14):        Candidate 1 is: `fail14997.Foo.this(int a)`
+fail_compilation/fail14997.d(15):        Candidate 2 is: `fail14997.Foo.this(string a)`
 ---
 */
 

compiler/test/fail_compilation/fail15616a.d

@@ -2,12 +2,12 @@
 TEST_OUTPUT:
 ---
 fail_compilation/fail15616a.d(41): Error: none of the overloads of `foo` are callable using argument types `(double)`
-fail_compilation/fail15616a.d(14):        Candidates are: `fail15616a.foo(int a)`
-fail_compilation/fail15616a.d(17):                        `fail15616a.foo(int a, int b)`
-fail_compilation/fail15616a.d(26):                        `fail15616a.foo(int a, int b, int c)`
-fail_compilation/fail15616a.d(29):                        `fail15616a.foo(string a)`
-fail_compilation/fail15616a.d(32):                        `fail15616a.foo(string a, string b)`
-fail_compilation\fail15616a.d(35):                        `fail15616a.foo(string a, string b, string c)`
+fail_compilation/fail15616a.d(14):        Candidate 1 is: `fail15616a.foo(int a)`
+fail_compilation/fail15616a.d(17):        Candidate 2 is: `fail15616a.foo(int a, int b)`
+fail_compilation/fail15616a.d(26):        Candidate 3 is: `fail15616a.foo(int a, int b, int c)`
+fail_compilation/fail15616a.d(29):        Candidate 4 is: `fail15616a.foo(string a)`
+fail_compilation/fail15616a.d(32):        Candidate 5 is: `fail15616a.foo(string a, string b)`
+fail_compilation/fail15616a.d(35):        Candidate 6 is: `fail15616a.foo(string a, string b, string c)`
 fail_compilation/fail15616a.d(41):        ... (2 more, -v to show) ...
 ---
 */