zclsyntax: fix parser infinite loops on certain EOF cases

The recovery functions in particular were not all properly handling EOF,
so they would spin forever looking for the right place to stop.

zcl/zclsyntax/parser.go

@@ -71,6 +71,7 @@ Token:
 			}
 		default:
 			bad := p.Read()
+			if !p.recovery {
 				if bad.Type == TokenOQuote {
 					diags = append(diags, &zcl.Diagnostic{
 						Severity: zcl.DiagError,
@@ -86,6 +87,7 @@ Token:
 						Subject:  &bad.Range,
 					})
 				}
+			}
 			endRange = p.PrevRange() // arbitrary, but somewhere inside the body means better diagnostics
 
 			p.recover(end) // attempt to recover to the token after the end of this body
@@ -169,6 +171,19 @@ Token:
 			diags = append(diags, labelDiags...)
 			labels = append(labels, label)
 			labelRanges = append(labelRanges, labelRange)
+			if labelDiags.HasErrors() {
+				p.recoverAfterBodyItem()
+				return &Block{
+					Type:   blockType,
+					Labels: labels,
+					Body:   nil,
+
+					TypeRange:       ident.Range,
+					LabelRanges:     labelRanges,
+					OpenBraceRange:  ident.Range, // placeholder
+					CloseBraceRange: ident.Range, // placeholder
+				}, diags
+			}
 
 		default:
 			switch tok.Type {
@@ -346,6 +361,8 @@ func (p *parser) recover(end TokenType) {
 			}
 
 			nest--
+		case TokenEOF:
+			return
 		}
 	}
 }
@@ -366,7 +383,7 @@ Token:
 	for {
 		tok := p.Read()
 		switch tok.Type {
-		case start:
+		case start, TokenEOF:
 			break Token
 		}
 	}