Start splitting completion into components

3 files changed, 316 insertions, 222 deletions

diff --git a/crates/ra_analysis/src/completion/complete_fn_param.rs b/crates/ra_analysis/src/completion/complete_fn_param.rs
new file mode 100644
index 000000000..d05a5e3cf
--- /dev/null
+++ b/crates/ra_analysis/src/completion/complete_fn_param.rs
@@ -0,0 +1,107 @@
+use ra_syntax::{
+    algo::{
+        visit::{visitor_ctx, VisitorCtx}
+    },
+    ast,
+    AstNode,
+};
+use rustc_hash::{FxHashMap};
+
+use crate::{
+    completion::{SyntaxContext, Completions, CompletionKind, CompletionItem},
+};
+
+/// Complete repeated parametes, both name and type. For example, if all
+/// functions in a file have a `spam: &mut Spam` parameter, a completion with
+/// `spam: &mut Spam` insert text/label and `spam` lookup string will be
+/// suggested.
+pub(super) fn complete_fn_param(acc: &mut Completions, ctx: &SyntaxContext) {
+    if !ctx.is_param {
+        return;
+    }
+
+    let mut params = FxHashMap::default();
+    for node in ctx.leaf.ancestors() {
+        let _ = visitor_ctx(&mut params)
+            .visit::<ast::SourceFile, _>(process)
+            .visit::<ast::ItemList, _>(process)
+            .accept(node);
+    }
+    params
+        .into_iter()
+        .filter_map(|(label, (count, param))| {
+            let lookup = param.pat()?.syntax().text().to_string();
+            if count < 2 {
+                None
+            } else {
+                Some((label, lookup))
+            }
+        })
+        .for_each(|(label, lookup)| {
+            CompletionItem::new(label)
+                .lookup_by(lookup)
+                .kind(CompletionKind::Magic)
+                .add_to(acc)
+        });
+
+    fn process<'a, N: ast::FnDefOwner<'a>>(
+        node: N,
+        params: &mut FxHashMap<String, (u32, ast::Param<'a>)>,
+    ) {
+        node.functions()
+            .filter_map(|it| it.param_list())
+            .flat_map(|it| it.params())
+            .for_each(|param| {
+                let text = param.syntax().text().to_string();
+                params.entry(text).or_insert((0, param)).0 += 1;
+            })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::completion::*;
+
+    fn check_magic_completion(code: &str, expected_completions: &str) {
+        check_completion(code, expected_completions, CompletionKind::Magic);
+    }
+
+    #[test]
+    fn test_param_completion_last_param() {
+        check_magic_completion(
+            r"
+            fn foo(file_id: FileId) {}
+            fn bar(file_id: FileId) {}
+            fn baz(file<|>) {}
+            ",
+            r#"file_id "file_id: FileId""#,
+        );
+    }
+
+    #[test]
+    fn test_param_completion_nth_param() {
+        check_magic_completion(
+            r"
+            fn foo(file_id: FileId) {}
+            fn bar(file_id: FileId) {}
+            fn baz(file<|>, x: i32) {}
+            ",
+            r#"file_id "file_id: FileId""#,
+        );
+    }
+
+    #[test]
+    fn test_param_completion_trait_param() {
+        check_magic_completion(
+            r"
+            pub(crate) trait SourceRoot {
+                pub fn contains(&self, file_id: FileId) -> bool;
+                pub fn module_map(&self) -> &ModuleMap;
+                pub fn lines(&self, file_id: FileId) -> &LineIndex;
+                pub fn syntax(&self, file<|>)
+            }
+            ",
+            r#"file_id "file_id: FileId""#,
+        );
+    }
+}
diff --git a/crates/ra_analysis/src/completion/complete_keywords.rs b/crates/ra_analysis/src/completion/complete_keywords.rs
new file mode 100644
index 000000000..d0a6ec19e
--- /dev/null
+++ b/crates/ra_analysis/src/completion/complete_keywords.rs
@@ -0,0 +1,206 @@
+use ra_syntax::{
+    algo::visit::{visitor, Visitor},
+    AstNode,
+    ast::{self, LoopBodyOwner},
+    SyntaxKind::*, SyntaxNodeRef,
+};
+
+use crate::{
+    completion::{SyntaxContext, CompletionItem, Completions, CompletionKind::*},
+};
+
+pub(super) fn complete_expr_keyword(acc: &mut Completions, ctx: &SyntaxContext) {
+    if !ctx.is_trivial_path {
+        return;
+    }
+    let fn_def = match ctx.enclosing_fn {
+        Some(it) => it,
+        None => return,
+    };
+    acc.add(keyword("if", "if $0 {}"));
+    acc.add(keyword("match", "match $0 {}"));
+    acc.add(keyword("while", "while $0 {}"));
+    acc.add(keyword("loop", "loop {$0}"));
+
+    if ctx.after_if {
+        acc.add(keyword("else", "else {$0}"));
+        acc.add(keyword("else if", "else if $0 {}"));
+    }
+    if is_in_loop_body(ctx.leaf) {
+        acc.add(keyword("continue", "continue"));
+        acc.add(keyword("break", "break"));
+    }
+    acc.add_all(complete_return(fn_def, ctx.is_stmt));
+}
+
+fn is_in_loop_body(leaf: SyntaxNodeRef) -> bool {
+    for node in leaf.ancestors() {
+        if node.kind() == FN_DEF || node.kind() == LAMBDA_EXPR {
+            break;
+        }
+        let loop_body = visitor()
+            .visit::<ast::ForExpr, _>(LoopBodyOwner::loop_body)
+            .visit::<ast::WhileExpr, _>(LoopBodyOwner::loop_body)
+            .visit::<ast::LoopExpr, _>(LoopBodyOwner::loop_body)
+            .accept(node);
+        if let Some(Some(body)) = loop_body {
+            if leaf.range().is_subrange(&body.syntax().range()) {
+                return true;
+            }
+        }
+    }
+    false
+}
+
+fn complete_return(fn_def: ast::FnDef, is_stmt: bool) -> Option<CompletionItem> {
+    let snip = match (is_stmt, fn_def.ret_type().is_some()) {
+        (true, true) => "return $0;",
+        (true, false) => "return;",
+        (false, true) => "return $0",
+        (false, false) => "return",
+    };
+    Some(keyword("return", snip))
+}
+
+fn keyword(kw: &str, snippet: &str) -> CompletionItem {
+    CompletionItem::new(kw)
+        .kind(Keyword)
+        .snippet(snippet)
+        .build()
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::completion::{CompletionKind, check_completion};
+    fn check_keyword_completion(code: &str, expected_completions: &str) {
+        check_completion(code, expected_completions, CompletionKind::Keyword);
+    }
+
+    #[test]
+    fn test_completion_kewords() {
+        check_keyword_completion(
+            r"
+            fn quux() {
+                <|>
+            }
+            ",
+            r#"
+            if "if $0 {}"
+            match "match $0 {}"
+            while "while $0 {}"
+            loop "loop {$0}"
+            return "return"
+            "#,
+        );
+    }
+
+    #[test]
+    fn test_completion_else() {
+        check_keyword_completion(
+            r"
+            fn quux() {
+                if true {
+                    ()
+                } <|>
+            }
+            ",
+            r#"
+            if "if $0 {}"
+            match "match $0 {}"
+            while "while $0 {}"
+            loop "loop {$0}"
+            else "else {$0}"
+            else if "else if $0 {}"
+            return "return"
+            "#,
+        );
+    }
+
+    #[test]
+    fn test_completion_return_value() {
+        check_keyword_completion(
+            r"
+            fn quux() -> i32 {
+                <|>
+                92
+            }
+            ",
+            r#"
+            if "if $0 {}"
+            match "match $0 {}"
+            while "while $0 {}"
+            loop "loop {$0}"
+            return "return $0;"
+            "#,
+        );
+        check_keyword_completion(
+            r"
+            fn quux() {
+                <|>
+                92
+            }
+            ",
+            r#"
+            if "if $0 {}"
+            match "match $0 {}"
+            while "while $0 {}"
+            loop "loop {$0}"
+            return "return;"
+            "#,
+        );
+    }
+
+    #[test]
+    fn test_completion_return_no_stmt() {
+        check_keyword_completion(
+            r"
+            fn quux() -> i32 {
+                match () {
+                    () => <|>
+                }
+            }
+            ",
+            r#"
+            if "if $0 {}"
+            match "match $0 {}"
+            while "while $0 {}"
+            loop "loop {$0}"
+            return "return $0"
+            "#,
+        );
+    }
+
+    #[test]
+    fn test_continue_break_completion() {
+        check_keyword_completion(
+            r"
+            fn quux() -> i32 {
+                loop { <|> }
+            }
+            ",
+            r#"
+            if "if $0 {}"
+            match "match $0 {}"
+            while "while $0 {}"
+            loop "loop {$0}"
+            continue "continue"
+            break "break"
+            return "return $0"
+            "#,
+        );
+        check_keyword_completion(
+            r"
+            fn quux() -> i32 {
+                loop { || { <|> } }
+            }
+            ",
+            r#"
+            if "if $0 {}"
+            match "match $0 {}"
+            while "while $0 {}"
+            loop "loop {$0}"
+            return "return $0"
+            "#,
+        );
+    }
+}
diff --git a/crates/ra_analysis/src/completion/reference_completion.rs b/crates/ra_analysis/src/completion/reference_completion.rs
index c2ac95453..15ff4c5dd 100644
--- a/crates/ra_analysis/src/completion/reference_completion.rs
+++ b/crates/ra_analysis/src/completion/reference_completion.rs
@@ -1,9 +1,7 @@
 use rustc_hash::{FxHashSet};
-use ra_editor::find_node_at_offset;
 use ra_syntax::{
-    algo::visit::{visitor, Visitor},
     SourceFileNode, AstNode,
-    ast::{self, LoopBodyOwner},
+    ast,
     SyntaxKind::*,
 };
 use hir::{
@@ -21,7 +19,7 @@ pub(super) fn completions(
     acc: &mut Completions,
     db: &RootDatabase,
     module: &hir::Module,
-    file: &SourceFileNode,
+    _file: &SourceFileNode,
     name_ref: ast::NameRef,
 ) -> Cancelable<()> {
     let kind = match classify_name_ref(name_ref) {
@@ -34,7 +32,7 @@ pub(super) fn completions(
             if let Some(fn_def) = enclosing_fn {
                 let scopes = FnScopes::new(fn_def);
                 complete_fn(name_ref, &scopes, acc);
-                complete_expr_keywords(&file, fn_def, name_ref, acc);
+                // complete_expr_keywords(&file, fn_def, name_ref, acc);
                 complete_expr_snippets(acc);
             }
 
@@ -182,91 +180,6 @@ fn ${1:feature}() {
         .add_to(acc);
 }
 
-fn complete_expr_keywords(
-    file: &SourceFileNode,
-    fn_def: ast::FnDef,
-    name_ref: ast::NameRef,
-    acc: &mut Completions,
-) {
-    acc.add(keyword("if", "if $0 {}"));
-    acc.add(keyword("match", "match $0 {}"));
-    acc.add(keyword("while", "while $0 {}"));
-    acc.add(keyword("loop", "loop {$0}"));
-
-    if let Some(off) = name_ref.syntax().range().start().checked_sub(2.into()) {
-        if let Some(if_expr) = find_node_at_offset::<ast::IfExpr>(file.syntax(), off) {
-            if if_expr.syntax().range().end() < name_ref.syntax().range().start() {
-                acc.add(keyword("else", "else {$0}"));
-                acc.add(keyword("else if", "else if $0 {}"));
-            }
-        }
-    }
-    if is_in_loop_body(name_ref) {
-        acc.add(keyword("continue", "continue"));
-        acc.add(keyword("break", "break"));
-    }
-    acc.add_all(complete_return(fn_def, name_ref));
-}
-
-fn is_in_loop_body(name_ref: ast::NameRef) -> bool {
-    for node in name_ref.syntax().ancestors() {
-        if node.kind() == FN_DEF || node.kind() == LAMBDA_EXPR {
-            break;
-        }
-        let loop_body = visitor()
-            .visit::<ast::ForExpr, _>(LoopBodyOwner::loop_body)
-            .visit::<ast::WhileExpr, _>(LoopBodyOwner::loop_body)
-            .visit::<ast::LoopExpr, _>(LoopBodyOwner::loop_body)
-            .accept(node);
-        if let Some(Some(body)) = loop_body {
-            if name_ref
-                .syntax()
-                .range()
-                .is_subrange(&body.syntax().range())
-            {
-                return true;
-            }
-        }
-    }
-    false
-}
-
-fn complete_return(fn_def: ast::FnDef, name_ref: ast::NameRef) -> Option<CompletionItem> {
-    // let is_last_in_block = name_ref.syntax().ancestors().filter_map(ast::Expr::cast)
-    //     .next()
-    //     .and_then(|it| it.syntax().parent())
-    //     .and_then(ast::Block::cast)
-    //     .is_some();
-
-    // if is_last_in_block {
-    //     return None;
-    // }
-
-    let is_stmt = match name_ref
-        .syntax()
-        .ancestors()
-        .filter_map(ast::ExprStmt::cast)
-        .next()
-    {
-        None => false,
-        Some(expr_stmt) => expr_stmt.syntax().range() == name_ref.syntax().range(),
-    };
-    let snip = match (is_stmt, fn_def.ret_type().is_some()) {
-        (true, true) => "return $0;",
-        (true, false) => "return;",
-        (false, true) => "return $0",
-        (false, false) => "return",
-    };
-    Some(keyword("return", snip))
-}
-
-fn keyword(kw: &str, snippet: &str) -> CompletionItem {
-    CompletionItem::new(kw)
-        .kind(Keyword)
-        .snippet(snippet)
-        .build()
-}
-
 fn complete_expr_snippets(acc: &mut Completions) {
     CompletionItem::new("pd")
         .snippet("eprintln!(\"$0 = {:?}\", $0);")
@@ -286,10 +199,6 @@ mod tests {
         check_completion(code, expected_completions, CompletionKind::Reference);
     }
 
-    fn check_keyword_completion(code: &str, expected_completions: &str) {
-        check_completion(code, expected_completions, CompletionKind::Keyword);
-    }
-
     fn check_snippet_completion(code: &str, expected_completions: &str) {
         check_completion(code, expected_completions, CompletionKind::Snippet);
     }
@@ -471,134 +380,6 @@ mod tests {
     }
 
     #[test]
-    fn test_completion_kewords() {
-        check_keyword_completion(
-            r"
-            fn quux() {
-                <|>
-            }
-            ",
-            r#"
-            if "if $0 {}"
-            match "match $0 {}"
-            while "while $0 {}"
-            loop "loop {$0}"
-            return "return"
-            "#,
-        );
-    }
-
-    #[test]
-    fn test_completion_else() {
-        check_keyword_completion(
-            r"
-            fn quux() {
-                if true {
-                    ()
-                } <|>
-            }
-            ",
-            r#"
-            if "if $0 {}"
-            match "match $0 {}"
-            while "while $0 {}"
-            loop "loop {$0}"
-            else "else {$0}"
-            else if "else if $0 {}"
-            return "return"
-            "#,
-        );
-    }
-
-    #[test]
-    fn test_completion_return_value() {
-        check_keyword_completion(
-            r"
-            fn quux() -> i32 {
-                <|>
-                92
-            }
-            ",
-            r#"
-            if "if $0 {}"
-            match "match $0 {}"
-            while "while $0 {}"
-            loop "loop {$0}"
-            return "return $0;"
-            "#,
-        );
-        check_keyword_completion(
-            r"
-            fn quux() {
-                <|>
-                92
-            }
-            ",
-            r#"
-            if "if $0 {}"
-            match "match $0 {}"
-            while "while $0 {}"
-            loop "loop {$0}"
-            return "return;"
-            "#,
-        );
-    }
-
-    #[test]
-    fn test_completion_return_no_stmt() {
-        check_keyword_completion(
-            r"
-            fn quux() -> i32 {
-                match () {
-                    () => <|>
-                }
-            }
-            ",
-            r#"
-            if "if $0 {}"
-            match "match $0 {}"
-            while "while $0 {}"
-            loop "loop {$0}"
-            return "return $0"
-            "#,
-        );
-    }
-
-    #[test]
-    fn test_continue_break_completion() {
-        check_keyword_completion(
-            r"
-            fn quux() -> i32 {
-                loop { <|> }
-            }
-            ",
-            r#"
-            if "if $0 {}"
-            match "match $0 {}"
-            while "while $0 {}"
-            loop "loop {$0}"
-            continue "continue"
-            break "break"
-            return "return $0"
-            "#,
-        );
-        check_keyword_completion(
-            r"
-            fn quux() -> i32 {
-                loop { || { <|> } }
-            }
-            ",
-            r#"
-            if "if $0 {}"
-            match "match $0 {}"
-            while "while $0 {}"
-            loop "loop {$0}"
-            return "return $0"
-            "#,
-        );
-    }
-
-    #[test]
     fn completes_snippets_in_expressions() {
         check_snippet_completion(
             r"fn foo(x: i32) { <|> }",