parser/checker: deduce type of global from initialization expression (#11005)

vlib/v/ast/scope.v

@@ -100,6 +100,16 @@ pub fn (s &Scope) find_var(name string) ?&Var {
 	return none
 }
 
+pub fn (s &Scope) find_global(name string) ?&GlobalField {
+	if obj := s.find(name) {
+		match obj {
+			GlobalField { return &obj }
+			else {}
+		}
+	}
+	return none
+}
+
 pub fn (s &Scope) find_const(name string) ?&ConstField {
 	if obj := s.find(name) {
 		match obj {

vlib/v/checker/checker.v

@@ -134,10 +134,24 @@ pub fn (mut c Checker) check(ast_file &ast.File) {
 			}
 		}
 	}
-	for stmt in ast_file.stmts {
+	for mut stmt in ast_file.stmts {
+		if stmt is ast.ConstDecl || stmt is ast.ExprStmt {
 			c.expr_level = 0
 			c.stmt(stmt)
 		}
+	}
+	for mut stmt in ast_file.stmts {
+		if stmt is ast.GlobalDecl {
+			c.expr_level = 0
+			c.stmt(stmt)
+		}
+	}
+	for mut stmt in ast_file.stmts {
+		if stmt !is ast.ConstDecl && stmt !is ast.GlobalDecl && stmt !is ast.ExprStmt {
+			c.expr_level = 0
+			c.stmt(stmt)
+		}
+	}
 	c.check_scope_vars(c.file.scope)
 }
 
@@ -4831,13 +4845,12 @@ fn (mut c Checker) global_decl(mut node ast.GlobalDecl) {
 		if sym.kind == .placeholder {
 			c.error('unknown type `$sym.name`', field.typ_pos)
 		}
-		if field.expr !is ast.EmptyExpr {
-			expr_typ := c.expr(field.expr)
-			if !c.check_types(expr_typ, field.typ) {
-				got_sym := c.table.get_type_symbol(expr_typ)
-				c.error('cannot initialize global variable `$field.name` of type `$sym.name` with expression of type `$got_sym.name`',
-					field.expr.position())
+		if field.has_expr {
+			field.typ = c.expr(field.expr)
+			mut v := c.file.global_scope.find_global(field.name) or {
+				panic('internal compiler error - could not find global in scope')
 			}
+			v.typ = c.table.mktyp(field.typ)
 		}
 		c.global_names << field.name
 	}
@@ -5569,7 +5582,7 @@ pub fn (mut c Checker) cast_expr(mut node ast.CastExpr) ast.Type {
 				c.mark_as_referenced(mut &node.expr, true)
 			}
 		}
-	} else if node.typ == ast.bool_type && !c.inside_unsafe {
+	} else if node.typ == ast.bool_type && node.expr_type != ast.bool_type && !c.inside_unsafe {
 		c.error('cannot cast to bool - use e.g. `some_int != 0` instead', node.pos)
 	} else if node.expr_type == ast.none_type && !node.typ.has_flag(.optional) {
 		type_name := c.table.type_to_str(node.typ)

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

@@ -1,3 +0,0 @@
-vlib/v/checker/tests/globals/assign_no_type.vv:1:21: error: global assign must have a type and value, use `name = type(value)` or `name type`
-    1 | __global ( test = 0 )
-      |                     ^

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

@@ -1 +0,0 @@
-__global ( test = 0 )

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

@@ -1,3 +1,3 @@
-vlib/v/checker/tests/globals/assign_no_value.vv:1:23: error: global assign must have a type and value, use `name = type(value)` or `name type`
+vlib/v/checker/tests/globals/assign_no_value.vv:1:19: error: undefined ident: `int`
     1 | __global ( test = int )
-      |                       ^
+      |                   ~~~

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

@@ -3,9 +3,9 @@ vlib/v/checker/tests/globals/unknown_typ.vv:1:12: error: unknown type `foo`
       |            ~~~
     2 | __global (
     3 |     y = float(5.0)
-vlib/v/checker/tests/globals/unknown_typ.vv:3:6: error: unknown type `float`
+vlib/v/checker/tests/globals/unknown_typ.vv:3:6: error: unknown function: float
     1 | __global x foo
     2 | __global (
     3 |     y = float(5.0)
-      |         ~~~~~
+      |         ~~~~~~~~~~
     4 | )

vlib/v/fmt/fmt.v

@@ -983,10 +983,7 @@ pub fn (mut f Fmt) global_decl(node ast.GlobalDecl) {
 		f.write(strings.repeat(` `, max - field.name.len))
 		if field.has_expr {
 			f.write('= ')
-			f.write(f.table.type_to_str_using_aliases(field.typ, f.mod2alias))
-			f.write('(')
 			f.expr(field.expr)
-			f.write(')')
 		} else {
 			f.write('${f.table.type_to_str_using_aliases(field.typ, f.mod2alias)}')
 		}

vlib/v/parser/parser.v

@@ -2937,24 +2937,47 @@ fn (mut p Parser) global_decl() ast.GlobalDecl {
 		pos := p.tok.position()
 		name := p.check_name()
 		has_expr := p.tok.kind == .assign
+		mut expr := ast.empty_expr()
+		mut typ := ast.void_type
+		mut typ_pos := token.Position{}
 		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)`')
-			return ast.GlobalDecl{}
-		}
-		mut expr := ast.empty_expr()
-		if has_expr {
-			if p.tok.kind != .lpar {
-				p.error('global assign must have a type and value, use `name = type(value)` or `name type`')
-				return ast.GlobalDecl{}
-			}
-			p.next() // (
 			expr = p.expr(0)
-			p.check(.rpar)
+			match expr {
+				ast.CastExpr {
+					typ = (expr as ast.CastExpr).typ
+				}
+				ast.StructInit {
+					typ = (expr as ast.StructInit).typ
+				}
+				ast.ArrayInit {
+					typ = (expr as ast.ArrayInit).typ
+				}
+				ast.ChanInit {
+					typ = (expr as ast.ChanInit).typ
+				}
+				ast.BoolLiteral, ast.IsRefType {
+					typ = ast.bool_type
+				}
+				ast.CharLiteral {
+					typ = ast.char_type
+				}
+				ast.FloatLiteral {
+					typ = ast.f64_type
+				}
+				ast.IntegerLiteral, ast.SizeOf {
+					typ = ast.int_type
+				}
+				ast.StringLiteral, ast.StringInterLiteral {
+					typ = ast.string_type
+				}
+				else {
+					// type will be deduced by checker
+				}
+			}
+		} else {
+			typ_pos = p.tok.position()
+			typ = p.parse_type()
 		}
 		field := ast.GlobalField{
 			name: name

vlib/v/tests/init_global_test.v

@@ -28,6 +28,30 @@ fn test_global_init() {
 	assert true
 }
 
+fn get_u64() u64 {
+	return 27
+}
+
+fn test_no_type() {
+	assert test == 0
+	assert typeof(test).name == 'int'
+	assert testf == 1.25
+	assert typeof(testf).name == 'f64'
+	assert testneg == -2
+	assert typeof(testneg).name == 'int'
+	assert testnegf == -1250000
+	assert typeof(testnegf).name == 'f64'
+	assert testexpl == 7
+	assert typeof(testexpl).name == 'f32'
+	assert testfn == 27
+	assert typeof(testfn).name == 'u64'
+	assert typeof(testarr).name == '[]f64'
+	assert testarr.len == 10
+	assert testarr[9] == 2.75
+	assert typeof(testmap).name == 'map[string]f64'
+	assert testmap['asd'] == -7.25
+}
+
 __global (
 	intmap    map[string]int
 	numberfns map[string]fn () int
@@ -38,6 +62,18 @@ __global (
 	mtx       sync.RwMutex
 	f1        = f64(545 / (sizeof(f64) + f32(8))) // directly initialized
 	f2        f64
+	test      = 0 // int
+	testf     = 1.25 // f64
+	testneg   = -2 // int
+	testnegf  = -1.25e06 // f64
+	testexpl  = f32(7)
+	testfn    = get_u64()
+	testarr   = []f64{len: 10, init: 2.75}
+	testmap   = map{
+		'qwe': 2.5
+		'asd': -7.25
+		'yxc': 3.125
+	}
 )
 
 fn init() {