From bec47e221fbd78a2e5f253e9418c4b86e243e35a Mon Sep 17 00:00:00 2001
From: Sergey Parilin <parilinsa@gmail.com>
Date: Mon, 14 Oct 2019 18:39:40 +0300
Subject: #1435 postfix completion for integer literals

---
 .../ra_ide_api/src/completion/complete_postfix.rs  | 67 +++++++++++++++++++++-
 .../src/completion/completion_context.rs           | 12 ++++
 2 files changed, 77 insertions(+), 2 deletions(-)

diff --git a/crates/ra_ide_api/src/completion/complete_postfix.rs b/crates/ra_ide_api/src/completion/complete_postfix.rs
index 445a02676..555cecb73 100644
--- a/crates/ra_ide_api/src/completion/complete_postfix.rs
+++ b/crates/ra_ide_api/src/completion/complete_postfix.rs
@@ -8,7 +8,7 @@ use crate::{
     CompletionItem,
 };
 use hir::{Ty, TypeCtor};
-use ra_syntax::{ast::AstNode, TextRange};
+use ra_syntax::{ast::AstNode, TextRange, TextUnit};
 use ra_text_edit::TextEditBuilder;
 
 fn postfix_snippet(ctx: &CompletionContext, label: &str, detail: &str, snippet: &str) -> Builder {
@@ -42,7 +42,13 @@ fn is_bool_or_unknown(ty: Option<Ty>) -> bool {
 
 pub(super) fn complete_postfix(acc: &mut Completions, ctx: &CompletionContext) {
     if let Some(dot_receiver) = &ctx.dot_receiver {
-        let receiver_text = dot_receiver.syntax().text().to_string();
+        let receiver_text = if ctx.dot_receiver_is_ambiguous_float_literal {
+            let text = dot_receiver.syntax().text();
+            let without_dot = ..text.len() - TextUnit::of_char('.');
+            text.slice(without_dot).to_string()
+        } else {
+            dot_receiver.syntax().text().to_string()
+        };
         let receiver_ty = ctx.analyzer.type_of(ctx.db, &dot_receiver);
         if is_bool_or_unknown(receiver_ty) {
             postfix_snippet(ctx, "if", "if expr {}", &format!("if {} {{$0}}", receiver_text))
@@ -206,6 +212,63 @@ mod tests {
         insert: "&mut bar",
         detail: "&mut expr",
     },
+]"###
+        );
+    }
+
+    #[test]
+    fn postfix_completion_works_for_ambiguous_float_literal() {
+        assert_debug_snapshot!(
+            do_postfix_completion(
+                r#"
+                fn main() {
+                    42.<|>
+                }
+                "#,
+            ),
+            @r###"[
+    CompletionItem {
+        label: "box",
+        source_range: [52; 52),
+        delete: [49; 52),
+        insert: "Box::new(42)",
+        detail: "Box::new(expr)",
+    },
+    CompletionItem {
+        label: "dbg",
+        source_range: [52; 52),
+        delete: [49; 52),
+        insert: "dbg!(42)",
+        detail: "dbg!(expr)",
+    },
+    CompletionItem {
+        label: "match",
+        source_range: [52; 52),
+        delete: [49; 52),
+        insert: "match 42 {\n    ${1:_} => {$0\\},\n}",
+        detail: "match expr {}",
+    },
+    CompletionItem {
+        label: "not",
+        source_range: [52; 52),
+        delete: [49; 52),
+        insert: "!42",
+        detail: "!expr",
+    },
+    CompletionItem {
+        label: "ref",
+        source_range: [52; 52),
+        delete: [49; 52),
+        insert: "&42",
+        detail: "&expr",
+    },
+    CompletionItem {
+        label: "refm",
+        source_range: [52; 52),
+        delete: [49; 52),
+        insert: "&mut 42",
+        detail: "&mut expr",
+    },
 ]"###
         );
     }
diff --git a/crates/ra_ide_api/src/completion/completion_context.rs b/crates/ra_ide_api/src/completion/completion_context.rs
index 73f3f3960..64cbc0f98 100644
--- a/crates/ra_ide_api/src/completion/completion_context.rs
+++ b/crates/ra_ide_api/src/completion/completion_context.rs
@@ -38,6 +38,7 @@ pub(crate) struct CompletionContext<'a> {
     pub(super) is_new_item: bool,
     /// The receiver if this is a field or method access, i.e. writing something.<|>
     pub(super) dot_receiver: Option<ast::Expr>,
+    pub(super) dot_receiver_is_ambiguous_float_literal: bool,
     /// If this is a call (method or function) in particular, i.e. the () are already there.
     pub(super) is_call: bool,
     pub(super) is_path_type: bool,
@@ -80,6 +81,7 @@ impl<'a> CompletionContext<'a> {
             is_call: false,
             is_path_type: false,
             has_type_args: false,
+            dot_receiver_is_ambiguous_float_literal: false,
         };
         ctx.fill(&original_parse, position.offset);
         Some(ctx)
@@ -235,6 +237,16 @@ impl<'a> CompletionContext<'a> {
                 .expr()
                 .map(|e| e.syntax().text_range())
                 .and_then(|r| find_node_with_range(original_file.syntax(), r));
+            self.dot_receiver_is_ambiguous_float_literal = if let Some(ast::Expr::Literal(l)) =
+                &self.dot_receiver
+            {
+                match l.kind() {
+                    ast::LiteralKind::FloatNumber { suffix: _ } => l.token().text().ends_with('.'),
+                    _ => false,
+                }
+            } else {
+                false
+            }
         }
         if let Some(method_call_expr) = ast::MethodCallExpr::cast(parent) {
             // As above
-- 
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