From 44627aff43bd53c927fb212b810ff0b0a005cb3e Mon Sep 17 00:00:00 2001
From: William Killerud <william@killerud.com>
Date: Sun, 4 Aug 2024 08:37:31 +0200
Subject: [PATCH] fix: suggest variables and functions as mixin parameters

---
 .../do-complete-interpolation.test.ts         | 30 +++++++++++++++++++
 .../features/__tests__/do-complete.test.ts    | 26 ++++++++++++++++
 .../src/features/do-complete.ts               |  6 ++++
 3 files changed, 62 insertions(+)

diff --git a/packages/language-services/src/features/__tests__/do-complete-interpolation.test.ts b/packages/language-services/src/features/__tests__/do-complete-interpolation.test.ts
index 62eb60d5..7404eef5 100644
--- a/packages/language-services/src/features/__tests__/do-complete-interpolation.test.ts
+++ b/packages/language-services/src/features/__tests__/do-complete-interpolation.test.ts
@@ -37,6 +37,36 @@ test("should not suggest mixin or placeholder in string interpolation", async ()
 	assert.isUndefined(items.find((item) => item.label === "%placeholder"));
 });
 
+test("should not suggest module mixin in string interpolation", async () => {
+	ls.configure({
+		completionSettings: {
+			suggestFromUseOnly: true,
+		},
+	});
+
+	const one = fileSystemProvider.createDocument(
+		["$primary: limegreen;", "@mixin mixin($a: 1, $b) {}"],
+		{
+			uri: "one.scss",
+		},
+	);
+	const two = fileSystemProvider.createDocument(
+		['@use "./one";', '.a { background: url("/#{one.'],
+		{
+			uri: "two.scss",
+		},
+	);
+
+	// emulate scanner of language service which adds workspace documents to the cache
+	ls.parseStylesheet(one);
+	ls.parseStylesheet(two);
+
+	const { items } = await ls.doComplete(two, Position.create(1, 29));
+	assert.equal(items.length, 1);
+	assert.ok(items.find((annotation) => annotation.label === "$primary"));
+	assert.isUndefined(items.find((item) => item.label === "mixin"));
+});
+
 test("should suggest symbol from a different document via @use when in string interpolation", async () => {
 	ls.configure({
 		completionSettings: {
diff --git a/packages/language-services/src/features/__tests__/do-complete.test.ts b/packages/language-services/src/features/__tests__/do-complete.test.ts
index b6fce9ce..d0131d46 100644
--- a/packages/language-services/src/features/__tests__/do-complete.test.ts
+++ b/packages/language-services/src/features/__tests__/do-complete.test.ts
@@ -524,3 +524,29 @@ test("should suggest function in @for $i from 1 through ", async () => {
 	assert.isUndefined(items.find((item) => item.label === "mixin"));
 	assert.isUndefined(items.find((item) => item.label === "%placeholder"));
 });
+
+test("should suggest variable and function as parameter to mixin, not mixin or placeholder", async () => {
+	ls.configure({
+		completionSettings: {
+			suggestAllFromOpenDocument: true,
+			suggestFromUseOnly: false,
+		},
+	});
+
+	const one = fileSystemProvider.createDocument([
+		'$name: "value";',
+		"@mixin mixin($a: 1, $b) {}",
+		"@function compare($a: 1, $b) {}",
+		"%placeholder { color: blue; }",
+		".a { @include mixin(",
+	]);
+
+	ls.parseStylesheet(one);
+
+	const { items } = await ls.doComplete(one, Position.create(4, 20));
+
+	assert.ok(items.find((item) => item.label === "$name"));
+	assert.ok(items.find((item) => item.label === "compare"));
+	assert.isUndefined(items.find((item) => item.label === "mixin"));
+	assert.isUndefined(items.find((item) => item.label === "%placeholder"));
+});
diff --git a/packages/language-services/src/features/do-complete.ts b/packages/language-services/src/features/do-complete.ts
index 0e6e2c1d..aca429fd 100644
--- a/packages/language-services/src/features/do-complete.ts
+++ b/packages/language-services/src/features/do-complete.ts
@@ -55,6 +55,7 @@ const rePropertyValue = /.*:\s*/;
 const reEmptyPropertyValue = /.*:\s*$/;
 const reQuotedValueInString = /["'](?:[^"'\\]|\\.)*["']/g;
 const reMixinReference = /.*@include\s+(.*)/;
+const reCompletedMixinWithParametersReference = /.*@include\s+(.*)\(/;
 const reComment = /^(.*\/\/|.*\/\*|\s*\*)/;
 const reSassDoc = /^[\\s]*\/{3}.*$/;
 const reQuotes = /["']/;
@@ -480,6 +481,11 @@ export class DoComplete extends LanguageFeature {
 
 		if (!isPropertyValue && reMixinReference.test(lineBeforePosition)) {
 			context.isMixinContext = true;
+			if (reCompletedMixinWithParametersReference.test(lineBeforePosition)) {
+				context.isMixinContext = false;
+				context.isVariableContext = true;
+				context.isFunctionContext = true;
+			}
 		}
 
 		return context;