Fix underflows when formatting certain call chains

For certain call chains the formatter wouldn't reset the indentation
correctly, resulting in an underflow for the indent count.

Changelog: fixed

Author: yorickpeterse

compiler/src/format.rs

@@ -2584,11 +2584,19 @@ impl Generator {
             Node::IndentNext(nodes) if wrap.is_enabled() => {
                 self.pending_indents += 1;
 
+                let before = self.pending_indents;
+
                 for n in nodes {
                     self.node(n, wrap);
                 }
 
-                self.indent -= 2;
+                // If we didn't encounter a new line, reset the state. If we do,
+                // we have to dedent the lines that follow.
+                if self.pending_indents == before {
+                    self.pending_indents -= 1;
+                } else {
+                    self.indent -= 2;
+                }
             }
             Node::IndentNext(nodes) => {
                 for n in nodes {

std/fixtures/fmt/indented_call_chains/input.inko

@@ -0,0 +1,13 @@
+fn foo {
+  aaa.aaaaaaaaaaaaaaaaa.bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb.cccc('aaaaaaaa').cccc('aaa').cccc(aaaa, bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb)
+  100
+}
+
+fn bar {
+  aaa.aaaaaaaaaaaaaaaaa.bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb.cccc('aaaaaaaa').cccc('aaa').cccc(aaaa)
+  100
+}
+
+fn baz {
+  # line
+}

std/fixtures/fmt/indented_call_chains/output.inko

@@ -0,0 +1,26 @@
+fn foo {
+  aaa
+    .aaaaaaaaaaaaaaaaa
+    .bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
+    .cccc('aaaaaaaa')
+    .cccc('aaa')
+    .cccc(
+      aaaa,
+      bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb,
+    )
+  100
+}
+
+fn bar {
+  aaa
+    .aaaaaaaaaaaaaaaaa
+    .bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
+    .cccc('aaaaaaaa')
+    .cccc('aaa')
+    .cccc(aaaa)
+  100
+}
+
+fn baz {
+  # line
+}