1 files changed, 189 insertions, 0 deletions
diff --git a/src/tools/rust-analyzer/crates/ide-completion/src/completions/snippet.rs b/src/tools/rust-analyzer/crates/ide-completion/src/completions/snippet.rs
new file mode 100644
index 000000000..66adb4286
--- /dev/null
+++ b/src/tools/rust-analyzer/crates/ide-completion/src/completions/snippet.rs
@@ -0,0 +1,189 @@
+//! This file provides snippet completions, like `pd` => `eprintln!(...)`.
+
+use hir::Documentation;
+use ide_db::{imports::insert_use::ImportScope, SnippetCap};
+
+use crate::{
+    context::{ExprCtx, ItemListKind, PathCompletionCtx, Qualified},
+    item::Builder,
+    CompletionContext, CompletionItem, CompletionItemKind, Completions, SnippetScope,
+};
+
+pub(crate) fn complete_expr_snippet(
+    acc: &mut Completions,
+    ctx: &CompletionContext<'_>,
+    path_ctx: &PathCompletionCtx,
+    &ExprCtx { in_block_expr, .. }: &ExprCtx,
+) {
+    if !matches!(path_ctx.qualified, Qualified::No) {
+        return;
+    }
+    if !ctx.qualifier_ctx.none() {
+        return;
+    }
+
+    let cap = match ctx.config.snippet_cap {
+        Some(it) => it,
+        None => return,
+    };
+
+    if !ctx.config.snippets.is_empty() {
+        add_custom_completions(acc, ctx, cap, SnippetScope::Expr);
+    }
+
+    if in_block_expr {
+        snippet(ctx, cap, "pd", "eprintln!(\"$0 = {:?}\", $0);").add_to(acc);
+        snippet(ctx, cap, "ppd", "eprintln!(\"$0 = {:#?}\", $0);").add_to(acc);
+        let item = snippet(
+            ctx,
+            cap,
+            "macro_rules",
+            "\
+macro_rules! $1 {
+    ($2) => {
+        $0
+    };
+}",
+        );
+        item.add_to(acc);
+    }
+}
+
+pub(crate) fn complete_item_snippet(
+    acc: &mut Completions,
+    ctx: &CompletionContext<'_>,
+    path_ctx: &PathCompletionCtx,
+    kind: &ItemListKind,
+) {
+    if !matches!(path_ctx.qualified, Qualified::No) {
+        return;
+    }
+    if !ctx.qualifier_ctx.none() {
+        return;
+    }
+    let cap = match ctx.config.snippet_cap {
+        Some(it) => it,
+        None => return,
+    };
+
+    if !ctx.config.snippets.is_empty() {
+        add_custom_completions(acc, ctx, cap, SnippetScope::Item);
+    }
+
+    // Test-related snippets shouldn't be shown in blocks.
+    if let ItemListKind::SourceFile | ItemListKind::Module = kind {
+        let mut item = snippet(
+            ctx,
+            cap,
+            "tmod (Test module)",
+            "\
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn ${1:test_name}() {
+        $0
+    }
+}",
+        );
+        item.lookup_by("tmod");
+        item.add_to(acc);
+
+        let mut item = snippet(
+            ctx,
+            cap,
+            "tfn (Test function)",
+            "\
+#[test]
+fn ${1:feature}() {
+    $0
+}",
+        );
+        item.lookup_by("tfn");
+        item.add_to(acc);
+
+        let item = snippet(
+            ctx,
+            cap,
+            "macro_rules",
+            "\
+macro_rules! $1 {
+    ($2) => {
+        $0
+    };
+}",
+        );
+        item.add_to(acc);
+    }
+}
+
+fn snippet(ctx: &CompletionContext<'_>, cap: SnippetCap, label: &str, snippet: &str) -> Builder {
+    let mut item = CompletionItem::new(CompletionItemKind::Snippet, ctx.source_range(), label);
+    item.insert_snippet(cap, snippet);
+    item
+}
+
+fn add_custom_completions(
+    acc: &mut Completions,
+    ctx: &CompletionContext<'_>,
+    cap: SnippetCap,
+    scope: SnippetScope,
+) -> Option<()> {
+    if ImportScope::find_insert_use_container(&ctx.token.parent()?, &ctx.sema).is_none() {
+        return None;
+    }
+    ctx.config.prefix_snippets().filter(|(_, snip)| snip.scope == scope).for_each(
+        |(trigger, snip)| {
+            let imports = match snip.imports(ctx) {
+                Some(imports) => imports,
+                None => return,
+            };
+            let body = snip.snippet();
+            let mut builder = snippet(ctx, cap, trigger, &body);
+            builder.documentation(Documentation::new(format!("```rust\n{}\n```", body)));
+            for import in imports.into_iter() {
+                builder.add_import(import);
+            }
+            builder.set_detail(snip.description.clone());
+            builder.add_to(acc);
+        },
+    );
+    None
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::{
+        tests::{check_edit_with_config, TEST_CONFIG},
+        CompletionConfig, Snippet,
+    };
+
+    #[test]
+    fn custom_snippet_completion() {
+        check_edit_with_config(
+            CompletionConfig {
+                snippets: vec![Snippet::new(
+                    &["break".into()],
+                    &[],
+                    &["ControlFlow::Break(())".into()],
+                    "",
+                    &["core::ops::ControlFlow".into()],
+                    crate::SnippetScope::Expr,
+                )
+                .unwrap()],
+                ..TEST_CONFIG
+            },
+            "break",
+            r#"
+//- minicore: try
+fn main() { $0 }
+"#,
+            r#"
+use core::ops::ControlFlow;
+
+fn main() { ControlFlow::Break(()) }
+"#,
+        );
+    }
+}