fix tests

tooling/nargo_fmt/src/config.rs

@@ -47,6 +47,7 @@ config! {
     remove_nested_parens: bool, true, "Remove nested parens";
     short_array_element_width_threshold: usize, 10, "Width threshold for an array element to be considered short";
     array_width: usize, 100, "Maximum width of an array literal before falling back to vertical formatting";
+    single_line_if_else_max_width: usize, 100, "Maximum line length for single line if-else expressions";
 }
 
 impl Config {

tooling/nargo_fmt/src/visitor.rs

@@ -198,7 +198,7 @@ struct Shape {
     indent: Indent,
 }
 
-#[derive(PartialEq, Eq)]
+#[derive(PartialEq, Eq, Debug)]
 pub(crate) enum ExpressionType {
     Statement,
     SubExpression,

tooling/nargo_fmt/src/visitor/expr.rs

@@ -186,32 +186,58 @@ impl FmtVisitor<'_> {
                 if allow_single_line {
                     let mut visitor = self.fork();
                     visitor.indent = Indent::default();
-                    if let Some(line) = visitor.format_if_single_line(*if_expr) {
+                    if let Some(line) = visitor.format_if_single_line(*if_expr.clone()) {
                         return line;
                     }
                 }
 
-                todo!()
+                self.format_if(*if_expr)
             }
-            ExpressionKind::Variable(_) => self.slice(span).to_string(),
-            ExpressionKind::Lambda(_) => todo!(),
-            ExpressionKind::Error => todo!(),
+            _ => self.slice(span).to_string(),
         }
     }
 
+    fn format_if(&self, if_expr: IfExpression) -> String {
+        let condition_str = self.format_subexpr(if_expr.condition);
+        let consequence_str = self.format_subexpr(if_expr.consequence);
+
+        let mut result = format!("if {condition_str} {consequence_str}");
+
+        if let Some(alternative) = if_expr.alternative {
+            let alternative = if let Some(ExpressionKind::If(if_expr)) =
+                extract_simple_expr(alternative.clone()).map(|expr| expr.kind)
+            {
+                self.format_if(*if_expr)
+            } else {
+                self.format_expr(alternative, ExpressionType::Statement)
+            };
+
+            result.push_str(" else ");
+            result.push_str(&alternative);
+        };
+
+        result
+    }
+
     fn format_if_single_line(&self, if_expr: IfExpression) -> Option<String> {
         let condition_str = self.format_subexpr(if_expr.condition);
-        let consequence_str =
-            self.format_subexpr(extract_simple_expr(if_expr.consequence).unwrap());
+        let consequence_str = self.format_subexpr(extract_simple_expr(if_expr.consequence)?);
+
+        let if_str = if let Some(alternative) = if_expr.alternative {
+            let alternative_str = if let Some(ExpressionKind::If(_)) =
+                extract_simple_expr(alternative.clone()).map(|expr| expr.kind)
+            {
+                return None;
+            } else {
+                self.format_expr(extract_simple_expr(alternative)?, ExpressionType::Statement)
+            };
 
-        if let Some(alternative_expr) = if_expr.alternative {
-            let alternative_str =
-                self.format_subexpr(extract_simple_expr(alternative_expr).unwrap());
             format!("if {} {{ {} }} else {{ {} }}", condition_str, consequence_str, alternative_str)
-                .into()
         } else {
-            format!("if {{{}}} {{{}}}", condition_str, consequence_str).into()
-        }
+            format!("if {{{}}} {{{}}}", condition_str, consequence_str)
+        };
+
+        (if_str.len() <= self.config.single_line_if_else_max_width).then_some(if_str)
     }
 
     fn format_struct_lit(

tooling/nargo_fmt/src/visitor/stmt.rs

@@ -8,7 +8,7 @@ impl super::FmtVisitor<'_> {
     pub(crate) fn visit_stmts(&mut self, stmts: Vec<Statement>) {
         let len = stmts.len();
 
-        for (Statement { kind, span }, index) in zip(stmts, 0..) {
+        for (Statement { kind, span }, index) in zip(stmts, 1..) {
             let is_last = index == len;
 
             match kind {

tooling/nargo_fmt/tests/expected/expr.nr

@@ -94,3 +94,29 @@ fn parenthesized() {
 fn constructor() {
     Point { x: 5, y: 10 };
 }
+
+fn if_expr() {
+    if true {
+        println("Hello :D");
+    }
+}
+
+fn return_if_expr() {
+    if true { 42 } else { 40 + 2 }
+}
+
+fn return_if_expr() {
+    if true {
+        42
+    };
+
+    if true { 42 } else { 40 + 2 }
+}
+
+fn if_if() {
+    if cond {
+        some();
+    } else {
+        none();
+    }.bar().baz();
+}

tooling/nargo_fmt/tests/expected/if.nr

@@ -0,0 +1,40 @@
+fn main() {
+    if false {
+        ();
+        ();
+    }
+
+    if false // lone if comment
+    {
+        ();
+        ();
+    }
+
+    let a = if 0 > 1 { 0 } else { 0 };
+
+    if true {
+        ();
+    } else if false {
+        ();
+        ();
+    } else {
+        ();
+        ();
+        ();
+    }
+
+    if true // else-if-chain if comment
+    {
+        ();
+    }
+    else if false // else-if-chain else-if comment
+    {
+        ();
+        ();
+    } else // else-if-chain else comment
+    {
+        ();
+        ();
+        ();
+    }
+}

tooling/nargo_fmt/tests/expected/nested_if_else.nr

@@ -1,3 +1,9 @@
 fn nested_if_else() {
-    if false { 1 } else if false { 2 } else { 3 }
+    if false {
+        1
+    } else if false {
+        2
+    } else {
+        3
+    }
 }

tooling/nargo_fmt/tests/input/expr.nr

@@ -103,4 +103,33 @@ fn parenthesized() {
 fn constructor() {
     Point{x :5,
     y:  10   };
+}
+
+fn if_expr() {
+    if true { println("Hello :D"); }
+}
+
+fn return_if_expr() {
+    if true {
+42
+}
+else
+{ 40 + 2 }
+}
+
+fn return_if_expr() {
+    if true {42};
+
+    if true { 
+        42 
+        } 
+        else { 
+            40 +
+         2 }
+}
+
+fn if_if() {
+if cond { some(); } else { none(); }
+        .bar()
+        .baz();
 }

tooling/nargo_fmt/tests/input/if.nr

@@ -0,0 +1,52 @@
+fn main() {
+    if false
+    {
+        ();
+        ();
+    }
+
+    if false // lone if comment
+    {
+        ();
+        ();
+    }
+
+
+    let a =
+        if 0 > 1 {
+            0
+        }
+        else
+        {
+            0
+        };
+
+
+    if true
+    {
+        ();
+    } else if false {
+        ();
+        ();
+    }
+    else {
+        ();
+        ();
+        ();
+    }
+
+    if true // else-if-chain if comment
+    {
+        ();
+    }
+    else if false // else-if-chain else-if comment
+    {
+        ();
+        ();
+    } else // else-if-chain else comment
+    {
+        ();
+        ();
+        ();
+    }
+}