Merge #1909

1909: move ast builder to a separate file r=matklad a=matklad



Co-authored-by: Aleksey Kladov <[email protected]>

1 files changed, 102 insertions, 0 deletions

diff --git a/crates/ra_assists/src/assists/replace_if_let_with_match.rs b/crates/ra_assists/src/assists/replace_if_let_with_match.rs
new file mode 100644
index 000000000..401835c57
--- /dev/null
+++ b/crates/ra_assists/src/assists/replace_if_let_with_match.rs
@@ -0,0 +1,102 @@
+use format_buf::format;
+use hir::db::HirDatabase;
+use ra_fmt::extract_trivial_expression;
+use ra_syntax::{ast, AstNode};
+
+use crate::{Assist, AssistCtx, AssistId};
+
+pub(crate) fn replace_if_let_with_match(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
+    let if_expr: ast::IfExpr = ctx.node_at_offset()?;
+    let cond = if_expr.condition()?;
+    let pat = cond.pat()?;
+    let expr = cond.expr()?;
+    let then_block = if_expr.then_branch()?;
+    let else_block = match if_expr.else_branch()? {
+        ast::ElseBranch::Block(it) => it,
+        ast::ElseBranch::IfExpr(_) => return None,
+    };
+
+    ctx.add_action(AssistId("replace_if_let_with_match"), "replace with match", |edit| {
+        let match_expr = build_match_expr(expr, pat, then_block, else_block);
+        edit.target(if_expr.syntax().text_range());
+        edit.replace_node_and_indent(if_expr.syntax(), match_expr);
+        edit.set_cursor(if_expr.syntax().text_range().start())
+    });
+
+    ctx.build()
+}
+
+fn build_match_expr(
+    expr: ast::Expr,
+    pat1: ast::Pat,
+    arm1: ast::BlockExpr,
+    arm2: ast::BlockExpr,
+) -> String {
+    let mut buf = String::new();
+    format!(buf, "match {} {{\n", expr.syntax().text());
+    format!(buf, "    {} => {}\n", pat1.syntax().text(), format_arm(&arm1));
+    format!(buf, "    _ => {}\n", format_arm(&arm2));
+    buf.push_str("}");
+    buf
+}
+
+fn format_arm(block: &ast::BlockExpr) -> String {
+    match extract_trivial_expression(block) {
+        None => block.syntax().text().to_string(),
+        Some(e) => format!("{},", e.syntax().text()),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::helpers::{check_assist, check_assist_target};
+
+    #[test]
+    fn test_replace_if_let_with_match_unwraps_simple_expressions() {
+        check_assist(
+            replace_if_let_with_match,
+            "
+impl VariantData {
+    pub fn is_struct(&self) -> bool {
+        if <|>let VariantData::Struct(..) = *self {
+            true
+        } else {
+            false
+        }
+    }
+}           ",
+            "
+impl VariantData {
+    pub fn is_struct(&self) -> bool {
+        <|>match *self {
+            VariantData::Struct(..) => true,
+            _ => false,
+        }
+    }
+}           ",
+        )
+    }
+
+    #[test]
+    fn replace_if_let_with_match_target() {
+        check_assist_target(
+            replace_if_let_with_match,
+            "
+impl VariantData {
+    pub fn is_struct(&self) -> bool {
+        if <|>let VariantData::Struct(..) = *self {
+            true
+        } else {
+            false
+        }
+    }
+}           ",
+            "if let VariantData::Struct(..) = *self {
+            true
+        } else {
+            false
+        }",
+        );
+    }
+}