Merge pull request rust-lang#19735 from A4-Tacks/improve-let-snippet

Improve the let code snippet

Author: Veykril

src/tools/rust-analyzer/crates/ide-completion/src/completions/expr.rs

@@ -363,9 +363,14 @@ pub(crate) fn complete_expr_path(
                     add_keyword("true", "true");
                     add_keyword("false", "false");
 
-                    if in_condition || in_block_expr {
-                        add_keyword("letm", "let mut $0");
-                        add_keyword("let", "let $0");
+                    if in_condition {
+                        add_keyword("letm", "let mut $1 = $0");
+                        add_keyword("let", "let $1 = $0");
+                    }
+
+                    if in_block_expr {
+                        add_keyword("letm", "let mut $1 = $0;");
+                        add_keyword("let", "let $1 = $0;");
                     }
 
                     if after_if_expr {

src/tools/rust-analyzer/crates/ide-completion/src/completions/keyword.rs

@@ -336,7 +336,7 @@ fn main() {
     }
 
     #[test]
-    fn completes_let_with_space() {
+    fn completes_let_in_block() {
         check_edit(
             "let",
             r#"
@@ -346,7 +346,7 @@ fn main() {
 "#,
             r#"
 fn main() {
-    let $0
+    let $1 = $0;
 }
 "#,
         );
@@ -359,7 +359,97 @@ fn main() {
 "#,
             r#"
 fn main() {
-    let mut $0
+    let mut $1 = $0;
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn completes_let_in_condition() {
+        check_edit(
+            "let",
+            r#"
+fn main() {
+    if $0 {}
+}
+"#,
+            r#"
+fn main() {
+    if let $1 = $0 {}
+}
+"#,
+        );
+        check_edit(
+            "letm",
+            r#"
+fn main() {
+    if $0 {}
+}
+"#,
+            r#"
+fn main() {
+    if let mut $1 = $0 {}
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn completes_let_in_no_empty_condition() {
+        check_edit(
+            "let",
+            r#"
+fn main() {
+    if $0x {}
+}
+"#,
+            r#"
+fn main() {
+    if let $1 = $0x {}
+}
+"#,
+        );
+        check_edit(
+            "letm",
+            r#"
+fn main() {
+    if $0x {}
+}
+"#,
+            r#"
+fn main() {
+    if let mut $1 = $0x {}
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn completes_let_in_condition_block() {
+        check_edit(
+            "let",
+            r#"
+fn main() {
+    if { $0 } {}
+}
+"#,
+            r#"
+fn main() {
+    if { let $1 = $0; } {}
+}
+"#,
+        );
+        check_edit(
+            "letm",
+            r#"
+fn main() {
+    if { $0 } {}
+}
+"#,
+            r#"
+fn main() {
+    if { let mut $1 = $0; } {}
 }
 "#,
         );