add c-style typedef and a built-in string alias

typedef T name; binds name to the type record of T, at the top level or
in a function (scoped to its block). string is a built-in alias for char*.
A type name straight before , or ) in a parameter list is the parameter's
name, so fn f(string) still works. The language server shows typedef T
name; on hover and highlights typedef as a keyword.

9 files changed, 56 insertions, 0 deletions

diff --git a/tests/langerrors/typedef_generic_bare.zc b/tests/langerrors/typedef_generic_bare.zc
new file mode 100644
index 0000000..5f3e906
--- /dev/null
+++ b/tests/langerrors/typedef_generic_bare.zc
@@ -0,0 +1,6 @@
+namespace;
+
+// expect: expected '<', found 'plain'
+struct box<T> { T item; };
+typedef box plain;
+fn main() { return 0; }
diff --git a/tests/langerrors/typedef_local_redefine.zc b/tests/langerrors/typedef_local_redefine.zc
new file mode 100644
index 0000000..e51c32f
--- /dev/null
+++ b/tests/langerrors/typedef_local_redefine.zc
@@ -0,0 +1,8 @@
+namespace;
+
+// expect: cell: already defined
+fn main() {
+	typedef int cell;
+	typedef char* cell;
+	return 0;
+}
diff --git a/tests/langerrors/typedef_redefine.zc b/tests/langerrors/typedef_redefine.zc
new file mode 100644
index 0000000..05085ec
--- /dev/null
+++ b/tests/langerrors/typedef_redefine.zc
@@ -0,0 +1,6 @@
+namespace;
+
+// expect: num: already defined
+typedef int num;
+typedef char* num;
+fn main() { return 0; }
diff --git a/tests/langerrors/typedef_scope.zc b/tests/langerrors/typedef_scope.zc
new file mode 100644
index 0000000..833e30e
--- /dev/null
+++ b/tests/langerrors/typedef_scope.zc
@@ -0,0 +1,8 @@
+namespace;
+
+// expect: expected ';', found 'x'
+fn main() {
+	{ typedef int cell; cell a = 1; }
+	cell x = 2;
+	return 0;
+}
diff --git a/tests/langerrors/typedef_string_redefine.zc b/tests/langerrors/typedef_string_redefine.zc
new file mode 100644
index 0000000..226a94e
--- /dev/null
+++ b/tests/langerrors/typedef_string_redefine.zc
@@ -0,0 +1,5 @@
+namespace;
+
+// expect: string: already defined
+typedef int string;
+fn main() { return 0; }
diff --git a/tests/langerrors/typedef_tag.zc b/tests/langerrors/typedef_tag.zc
new file mode 100644
index 0000000..70ab491
--- /dev/null
+++ b/tests/langerrors/typedef_tag.zc
@@ -0,0 +1,5 @@
+namespace;
+
+// expect: a typedef names a type, which has no tag
+typedef char*.u owned;
+fn main() { return 0; }
diff --git a/tests/langerrors/typedef_unknown.zc b/tests/langerrors/typedef_unknown.zc
new file mode 100644
index 0000000..8076e86
--- /dev/null
+++ b/tests/langerrors/typedef_unknown.zc
@@ -0,0 +1,5 @@
+namespace;
+
+// expect: missing_t: isn't a type
+typedef missing_t thing;
+fn main() { return 0; }
diff --git a/tests/langerrors/typedef_variable_clash.zc b/tests/langerrors/typedef_variable_clash.zc
new file mode 100644
index 0000000..2c843f2
--- /dev/null
+++ b/tests/langerrors/typedef_variable_clash.zc
@@ -0,0 +1,8 @@
+namespace;
+
+// expect: count: already defined
+fn main() {
+	int count = 1;
+	typedef int count;
+	return count;
+}
diff --git a/tests/langerrors/typedef_void_variable.zc b/tests/langerrors/typedef_void_variable.zc
new file mode 100644
index 0000000..c5c7ced
--- /dev/null
+++ b/tests/langerrors/typedef_void_variable.zc
@@ -0,0 +1,5 @@
+namespace;
+
+// expect: a variable can't be void
+typedef void nothing;
+fn main() { nothing x; return 0; }