checker: check __global type (#9804)

vlib/v/ast/ast.v

@@ -519,6 +519,7 @@ pub:
 	expr     Expr
 	has_expr bool
 	pos      token.Position
+	typ_pos  token.Position
 pub mut:
 	typ      Type
 	comments []Comment

vlib/v/checker/checker.v

@@ -3834,6 +3834,10 @@ fn (mut c Checker) global_decl(node ast.GlobalDecl) {
 		if field.name in c.global_names {
 			c.error('duplicate global `$field.name`', field.pos)
 		}
+		sym := c.table.get_type_symbol(field.typ)
+		if sym.kind == .placeholder {
+			c.error('unknown type `$sym.name`', field.typ_pos)
+		}
 		c.global_names << field.name
 	}
 }

vlib/v/checker/tests/globals/unknown_typ.out

@@ -0,0 +1,11 @@
+vlib/v/checker/tests/globals/unknown_typ.vv:1:12: error: unknown type `foo`
+    1 | __global x foo
+      |            ~~~
+    2 | __global (
+    3 |     y = float(5.0)
+vlib/v/checker/tests/globals/unknown_typ.vv:3:6: error: unknown type `float`
+    1 | __global x foo
+    2 | __global (
+    3 |     y = float(5.0)
+      |         ~~~~~
+    4 | )

vlib/v/checker/tests/globals/unknown_typ.vv

@@ -0,0 +1,4 @@
+__global x foo
+__global (
+	y = float(5.0)
+)

vlib/v/parser/parser.v

@@ -2846,6 +2846,7 @@ fn (mut p Parser) global_decl() ast.GlobalDecl {
 		if has_expr {
 			p.next() // =
 		}
+		typ_pos := p.tok.position()
 		typ := p.parse_type()
 		if p.tok.kind == .assign {
 			p.error('global assign must have the type around the value, use `name = type(value)`')
@@ -2866,6 +2867,7 @@ fn (mut p Parser) global_decl() ast.GlobalDecl {
 			has_expr: has_expr
 			expr: expr
 			pos: pos
+			typ_pos: typ_pos
 			typ: typ
 			comments: comments
 		}