Revert "parser: Support `unsafe(expr)` (#5973)"

This reverts commit 19c226fcf8.

doc/docs.md

@@ -1907,10 +1907,10 @@ To mark potentially memory-unsafe operations, enclose them in an `unsafe` block:
 
 ```v
 // allocate 2 uninitialized bytes & return a reference to them
-mut p := unsafe(&byte(malloc(2)))
+mut p := unsafe { &byte(malloc(2)) }
 p[0] = `h` // Error: pointer indexing is only allowed in `unsafe` blocks
 unsafe {
-    p[0] = `h` // OK
+    p[0] = `h`
     p[1] = `i`
 }
 p++ // Error: pointer arithmetic is only allowed in `unsafe` blocks
@@ -1920,12 +1920,13 @@ unsafe {
 assert *p == `i`
 ```
 
-Best practice is to avoid putting memory-safe expressions inside an `unsafe` expression/block,
+Best practice is to avoid putting memory-safe expressions inside an `unsafe` block,
 so that the reason for using `unsafe` is as clear as possible. Generally any code 
-you think is memory-safe should be verified by the compiler.
+you think is memory-safe should not be inside an `unsafe` block, so the compiler 
+can verify it.
 
 If you suspect your program does violate memory-safety, you have a head start on 
-finding the cause: look for the `unsafe` keyword (and how it affects the
+finding the cause: look at the `unsafe` blocks (and how they interact with 
 surrounding code).
 
 * Note: This is work in progress.

vlib/v/ast/ast.v

@@ -728,7 +728,6 @@ pub:
 pub struct ParExpr {
 pub:
 	expr Expr
-	is_unsafe bool // unsafe(expr)
 }
 
 pub struct GoStmt {

vlib/v/checker/checker.v

@@ -2385,14 +2385,7 @@ pub fn (mut c Checker) expr(node ast.Expr) table.Type {
 			return table.void_type
 		}
 		ast.ParExpr {
-			if !node.is_unsafe {
-				return c.expr(node.expr)
-			}
-			assert !c.inside_unsafe
-			c.inside_unsafe = true
-			t := c.expr(node.expr)
-			c.inside_unsafe = false
-			return t
+			return c.expr(node.expr)
 		}
 		ast.RangeExpr {
 			// never happens

vlib/v/fmt/fmt.v

@@ -902,9 +902,6 @@ pub fn (mut f Fmt) expr(node ast.Expr) {
 			panic('fmt: OrExpr should to linked to CallExpr')
 		}
 		ast.ParExpr {
-			if node.is_unsafe {
-				f.write('unsafe')
-			}
 			f.write('(')
 			f.par_level++
 			f.expr(node.expr)

vlib/v/parser/parser.v

@@ -602,22 +602,13 @@ pub fn (mut p Parser) stmt(is_top_level bool) ast.Stmt {
 			}
 		}
 		.key_unsafe {
-			// unsafe {
-			if p.peek_tok.kind == .lcbr {
-				p.next()
-				assert !p.inside_unsafe
-				p.inside_unsafe = true
-				stmts := p.parse_block()
-				p.inside_unsafe = false
-				return ast.UnsafeStmt{
-					stmts: stmts
-				}
-			}
-			// unsafe(
-			pos := p.tok.position()
-			return ast.ExprStmt{
-				expr: p.expr(0)
-				pos: pos
+			p.next()
+			assert !p.inside_unsafe
+			p.inside_unsafe = true
+			stmts := p.parse_block()
+			p.inside_unsafe = false
+			return ast.UnsafeStmt{
+				stmts: stmts
 			}
 		}
 		.hash {

vlib/v/parser/pratt.v

@@ -93,23 +93,12 @@ pub fn (mut p Parser) expr(precedence int) ast.Expr {
 			pos := p.tok.position()
 			assert !p.inside_unsafe
 			p.inside_unsafe = true
-			if p.tok.kind == .lpar {
-				// unsafe(
-				p.check(.lpar)
-				node = ast.ParExpr{
-					expr: p.expr(0)
-					is_unsafe: true
-				}
-				p.check(.rpar)
-			} else {
-				// unsafe {
-				// old syntax, UnsafeExpr can be removed later
-				node = ast.UnsafeExpr{
-					stmts: p.parse_block()
-					pos: pos
-				}
-			}
+			stmts := p.parse_block()
 			p.inside_unsafe = false
+			node = ast.UnsafeExpr{
+				stmts: stmts
+				pos: pos
+			}
 		}
 		.key_lock, .key_rlock {
 			node = p.lock_expr()

vlib/v/tests/unsafe_test.v

@@ -3,9 +3,17 @@ fn test_ptr_assign() {
 	mut p := &v[0]
 	unsafe {
 		(*p)++
-		p++ // p now points to v[1]
+	}
+	unsafe {
+		p++
+	} // p now points to v[1]
+	unsafe {
 		(*p) += 2
-		p += 2 // p now points to v[3]
+	}
+	unsafe {
+		p += 2
+	} // p now points to v[3]
+	unsafe {
 		*p = 31
 	}
 	assert v[0] == 6
@@ -16,9 +24,16 @@ fn test_ptr_assign() {
 
 fn test_ptr_infix() {
 	v := 4
-	mut q := unsafe(&v - 1)
-	q = unsafe(q + 3)
-	assert q == unsafe(&v + 2)
+	mut q := unsafe {
+		&v - 1
+	}
+	
+	q = unsafe {
+		q + 3
+	}
+	
+	_ := q
+	_ := v
 }
 
 struct S1 {