Fix formatting of negative numbers in pnc apply patterns

crates/compiler/fmt/src/annotation.rs

@@ -56,6 +56,7 @@ pub enum Parens {
     InAsPattern,
     InApplyLastArg,
     InClosurePattern,
+    InPncApplyFunc,
 }
 
 /// In an AST node, do we show newlines around it

crates/compiler/fmt/src/node.rs

@@ -205,6 +205,7 @@ impl From<Parens> for Prec {
             Parens::InFunctionType => Prec::FunctionType,
             Parens::InOperator => Prec::FunctionType,
             Parens::InAsPattern => Prec::AsType,
+            Parens::InPncApplyFunc => Prec::Term,
         }
     }
 }

crates/compiler/fmt/src/pattern.rs

@@ -277,7 +277,8 @@ fn fmt_pattern_only(
 
         Pattern::NumLiteral(string) => {
             buf.indent(indent);
-            let needs_parens = parens == Parens::InClosurePattern;
+            let needs_parens = parens == Parens::InClosurePattern
+                || (parens == Parens::InPncApplyFunc && string.starts_with('-'));
             if needs_parens {
                 buf.push('(');
             }
@@ -419,6 +420,7 @@ fn fmt_pattern_only(
         Pattern::As(pattern, pattern_as) => {
             let needs_parens = parens == Parens::InAsPattern
                 || parens == Parens::InApply
+                || parens == Parens::InPncApplyFunc
                 || parens == Parens::InClosurePattern;
 
             if needs_parens {
@@ -472,7 +474,9 @@ pub fn pattern_fmt_apply(
     buf.indent(indent);
     // Sometimes, an Apply pattern needs parens around it.
     // In particular when an Apply's argument is itself an Apply (> 0) arguments
-    let parens = !args.is_empty() && parens == Parens::InApply && !use_commas_and_parens;
+    let parens = !args.is_empty()
+        && (parens == Parens::InApply || parens == Parens::InPncApplyFunc)
+        && !use_commas_and_parens;
 
     let indent_more = if is_multiline {
         indent + INDENT
@@ -494,7 +498,17 @@ pub fn pattern_fmt_apply(
         }
     }
 
-    fmt_pattern_only(&func.item, buf, Parens::InApply, indent, is_multiline);
+    fmt_pattern_only(
+        &func.item,
+        buf,
+        if is_pnc {
+            Parens::InPncApplyFunc
+        } else {
+            Parens::InApply
+        },
+        indent,
+        is_multiline,
+    );
 
     if use_commas_and_parens {
         buf.push('(');

crates/compiler/test_syntax/tests/snapshots/pass/pnc_apply_neg_pattern.expr.formatted.roc

@@ -0,0 +1,2 @@
+(-8)() : C
+8

crates/compiler/test_syntax/tests/snapshots/pass/pnc_apply_neg_pattern.expr.result-ast

@@ -0,0 +1,46 @@
+@0-10 SpaceAfter(
+    Defs(
+        Defs {
+            tags: [
+                EitherIndex(2147483648),
+            ],
+            regions: [
+                @0-8,
+            ],
+            space_before: [
+                Slice<roc_parse::ast::CommentOrNewline> { start: 0, length: 0 },
+            ],
+            space_after: [
+                Slice<roc_parse::ast::CommentOrNewline> { start: 0, length: 0 },
+            ],
+            spaces: [],
+            type_defs: [],
+            value_defs: [
+                Annotation(
+                    @1-6 PncApply(
+                        @1-3 NumLiteral(
+                            "-8",
+                        ),
+                        [],
+                    ),
+                    @7-8 Apply(
+                        "",
+                        "C",
+                        [],
+                    ),
+                ),
+            ],
+        },
+        @9-10 SpaceBefore(
+            Num(
+                "8",
+            ),
+            [
+                Newline,
+            ],
+        ),
+    ),
+    [
+        Newline,
+    ],
+)

crates/compiler/test_syntax/tests/snapshots/pass/pnc_apply_neg_pattern.expr.roc

@@ -0,0 +1,2 @@
+(-8)():C
+8

crates/compiler/test_syntax/tests/test_snapshots.rs

@@ -639,6 +639,7 @@ mod test_snapshots {
         pass/plus_if.expr,
         pass/plus_when.expr,
         pass/pnc_apply_comment_after_newline.expr,
+        pass/pnc_apply_neg_pattern.expr,
         pass/pnc_parens_apply_etc.expr,
         pass/pos_inf_float.expr,
         pass/positive_float.expr,