Deny unreachable-pub

It's very useful when `pub` is equivalent to "this is crate's public
API", let's enforce this!

Ideally, we should enforce it for local `cargo test`, and only during
CI, but that needs https://github.com/rust-lang/cargo/issues/5034.

crates/syntax/src/ast.rs

@@ -17,7 +17,7 @@ use crate::{
 
 pub use self::{
     expr_ext::{ArrayExprKind, BinOp, Effect, ElseBranch, LiteralKind, PrefixOp, RangeOp},
-    generated::*,
+    generated::{nodes::*, tokens::*},
     node_ext::{
         AttrKind, FieldKind, NameOrNameRef, PathSegmentKind, SelfParamKind, SlicePatComponents,
         StructKind, TypeBoundKind, VisibilityKind,

crates/syntax/src/ast/generated.rs

@@ -1,8 +1,8 @@
 //! This file is actually hand-written, but the submodules are indeed generated.
 #[rustfmt::skip]
-mod nodes;
+pub(crate) mod nodes;
 #[rustfmt::skip]
-mod tokens;
+pub(crate) mod tokens;
 
 use crate::{
     AstNode,
@@ -10,7 +10,7 @@ use crate::{
     SyntaxNode,
 };
 
-pub use {nodes::*, tokens::*};
+pub(crate) use nodes::*;
 
 // Stmt is the only nested enum, so it's easier to just hand-write it
 impl AstNode for Stmt {

crates/syntax/src/lib.rs

@@ -46,16 +46,19 @@ use text_edit::Indel;
 pub use crate::{
     algo::InsertPosition,
     ast::{AstNode, AstToken},
-    parsing::{lex_single_syntax_kind, lex_single_valid_syntax_kind, tokenize, Token},
+    parsing::lexer::{lex_single_syntax_kind, lex_single_valid_syntax_kind, tokenize, Token},
     ptr::{AstPtr, SyntaxNodePtr},
     syntax_error::SyntaxError,
     syntax_node::{
-        Direction, GreenNode, NodeOrToken, SyntaxElement, SyntaxElementChildren, SyntaxNode,
-        SyntaxNodeChildren, SyntaxToken, SyntaxTreeBuilder,
+        SyntaxElement, SyntaxElementChildren, SyntaxNode, SyntaxNodeChildren, SyntaxToken,
+        SyntaxTreeBuilder,
     },
 };
 pub use parser::{SyntaxKind, T};
-pub use rowan::{SmolStr, SyntaxText, TextRange, TextSize, TokenAtOffset, WalkEvent};
+pub use rowan::{
+    Direction, GreenNode, NodeOrToken, SmolStr, SyntaxText, TextRange, TextSize, TokenAtOffset,
+    WalkEvent,
+};
 
 /// `Parse` is the result of the parsing: a syntax tree and a collection of
 /// errors.

crates/syntax/src/parsing.rs

@@ -1,7 +1,7 @@
 //! Lexing, bridging to parser (which does the actual parsing) and
 //! incremental reparsing.
 
-mod lexer;
+pub(crate) mod lexer;
 mod text_token_source;
 mod text_tree_sink;
 mod reparsing;
@@ -10,7 +10,7 @@ use crate::{syntax_node::GreenNode, AstNode, SyntaxError, SyntaxNode};
 use text_token_source::TextTokenSource;
 use text_tree_sink::TextTreeSink;
 
-pub use lexer::*;
+pub(crate) use lexer::*;
 
 pub(crate) use self::reparsing::incremental_reparse;
 use parser::SyntaxKind;

crates/syntax/src/parsing/text_token_source.rs

@@ -65,7 +65,7 @@ fn mk_token(pos: usize, token_offset_pairs: &[(Token, TextSize)]) -> parser::Tok
 
 impl<'t> TextTokenSource<'t> {
     /// Generate input from tokens(expect comment and whitespace).
-    pub fn new(text: &'t str, raw_tokens: &'t [Token]) -> TextTokenSource<'t> {
+    pub(crate) fn new(text: &'t str, raw_tokens: &'t [Token]) -> TextTokenSource<'t> {
         let token_offset_pairs: Vec<_> = raw_tokens
             .iter()
             .filter_map({

crates/syntax/src/syntax_node.rs

@@ -10,9 +10,7 @@ use rowan::{GreenNodeBuilder, Language};
 
 use crate::{Parse, SmolStr, SyntaxError, SyntaxKind, TextSize};
 
-pub use rowan::GreenNode;
-
-pub(crate) use rowan::GreenToken;
+pub(crate) use rowan::{GreenNode, GreenToken, NodeOrToken};
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub enum RustLanguage {}
@@ -34,8 +32,6 @@ pub type SyntaxElement = rowan::SyntaxElement<RustLanguage>;
 pub type SyntaxNodeChildren = rowan::SyntaxNodeChildren<RustLanguage>;
 pub type SyntaxElementChildren = rowan::SyntaxElementChildren<RustLanguage>;
 
-pub use rowan::{Direction, NodeOrToken};
-
 #[derive(Default)]
 pub struct SyntaxTreeBuilder {
     errors: Vec<SyntaxError>,