Improve error for default args #2096. Deprecated old inference with slice copy. Copying must now ensure a slicing operator at the end of the right hand side: foo[1..2] = bar[..] rather than the old foo[1..2] = bar. The old behaviour can be mostly retained with --use-old-slice-copy).

test/test_suite/expressions/bad_number_args_2096.c3

@@ -0,0 +1,11 @@
+fn void foo(int a, int b, bool c = false) {}
+fn void foo2(int a, int b, bool c) {}
+
+fn int main()
+{
+	foo(2); // #error: 1-2 additional arguments were expected
+	foo2(2);// #error: 2 more arguments
+	foo();  // #error: expects 2-3 parameters
+	foo2(); // #error: expects 3 parameter(s)
+	return 0;
+}

test/test_suite/functions/vararg_and_named_tests.c3

@@ -44,7 +44,7 @@ fn void multiple(int x, int y) {}
 
 fn void f()
 {
-	multiple(1); // #error: Expected 1 more argument after this one
+	multiple(1); // #error:1 more argument was expected after this one
 }
 
 fn void g()

test/test_suite/slices/slice_assign_designated_2095.c3

@@ -0,0 +1,16 @@
+module test;
+
+struct Struct
+{
+	int field;
+}
+
+fn int main()
+{
+	Struct[4] arr;
+
+	arr[1] = {.field = 1};
+	arr[1..2] = {1};
+	arr[1..2] = {.field = 1};
+	return 0;
+}

test/test_suite/slices/slice_scalar.c3

@@ -0,0 +1,7 @@
+fn void assign_slice()
+{
+	int[8] a;
+	a[2..3] = { 1, 2 }; // #error: Maybe you wanted to do a slice copy
+	a[5..7] = 5;
+	assert(a == (int[8]){ 0, 0, 1, 2, 0, 5, 5, 5});
+}

test/unit/regression/slice_assign.c3

@@ -3,7 +3,7 @@ module slice_assign @test;
 fn void assign_slice()
 {
 	int[8] a;
-	a[2..3] = { 1, 2 };
+	a[2..3] = { 1, 2 }[..];
 	a[5..7] = 5;
 	assert(a == (int[8]){ 0, 0, 1, 2, 0, 5, 5, 5});
 }