[dev.typeparams] all: merge master (296ddf2) into dev.typeparams

Conflicts:

- src/runtime/runtime2.go

  On master, CL 317191 fixed the mentions of gc/reflect.go in comments
  to reflectdata/reflect.go; but on dev.typeparams, CL 325921 fixed
  that the same comment to reflect that deferstruct actually ended up
  in ssagen/ssa.go.

Merge List:

+ 2021-07-08 296ddf2a93 net: filter bad names from Lookup functions instead of hard failing
+ 2021-07-08 ce76298ee7 Update oudated comment
+ 2021-07-08 2ca44fe221 doc/go1.17: linkify time.UnixMilli and time.UnixMicro
+ 2021-07-07 5c59e11f5e cmd/compile: remove special-casing of blank in types.sconv{,2}
+ 2021-07-07 b003a8b1ae cmd/compile: optimize types.sconv
+ 2021-07-07 11f5df2d67 cmd/compile: extract pkgqual from symfmt
+ 2021-07-07 991fd381d5 cmd/go: don't lock .mod and .sum files for read in overlay
+ 2021-07-07 186a3bb4b0 cmd/go/internal/modfetch/codehost: skip hg tests if no hg binary is present
+ 2021-07-07 00c00558e1 cmd/go/internal/modload: remove unused functions
+ 2021-07-07 f264879f74 cmd/go/internal/modload: fix an apparent typo in the AutoRoot comment
+ 2021-07-07 c96833e5ba doc: remove stale comment about arm64 port

Change-Id: I849046b6d8f7421f60323549f3f763ef418bf9e7

1 files changed, 27 insertions, 30 deletions

diff --git a/src/cmd/compile/internal/types/fmt.go b/src/cmd/compile/internal/types/fmt.go
index 095b795d03..a52dd060a0 100644
--- a/src/cmd/compile/internal/types/fmt.go
+++ b/src/cmd/compile/internal/types/fmt.go
@@ -109,14 +109,18 @@ func sconv(s *Sym, verb rune, mode fmtMode) string {
 		return "<S>"
 	}
 
-	if s.Name == "_" {
-		return "_"
+	q := pkgqual(s.Pkg, verb, mode)
+	if q == "" {
+		return s.Name
 	}
+
 	buf := fmtBufferPool.Get().(*bytes.Buffer)
 	buf.Reset()
 	defer fmtBufferPool.Put(buf)
 
-	symfmt(buf, s, verb, mode)
+	buf.WriteString(q)
+	buf.WriteByte('.')
+	buf.WriteString(s.Name)
 	return InternString(buf.Bytes())
 }
 
@@ -128,56 +132,49 @@ func sconv2(b *bytes.Buffer, s *Sym, verb rune, mode fmtMode) {
 		b.WriteString("<S>")
 		return
 	}
-	if s.Name == "_" {
-		b.WriteString("_")
-		return
-	}
 
 	symfmt(b, s, verb, mode)
 }
 
 func symfmt(b *bytes.Buffer, s *Sym, verb rune, mode fmtMode) {
+	if q := pkgqual(s.Pkg, verb, mode); q != "" {
+		b.WriteString(q)
+		b.WriteByte('.')
+	}
+	b.WriteString(s.Name)
+}
+
+// pkgqual returns the qualifier that should be used for printing
+// symbols from the given package in the given mode.
+// If it returns the empty string, no qualification is needed.
+func pkgqual(pkg *Pkg, verb rune, mode fmtMode) string {
 	if verb != 'S' {
 		switch mode {
 		case fmtGo: // This is for the user
-			if s.Pkg == BuiltinPkg || s.Pkg == LocalPkg {
-				b.WriteString(s.Name)
-				return
+			if pkg == BuiltinPkg || pkg == LocalPkg {
+				return ""
 			}
 
 			// If the name was used by multiple packages, display the full path,
-			if s.Pkg.Name != "" && NumImport[s.Pkg.Name] > 1 {
-				fmt.Fprintf(b, "%q.%s", s.Pkg.Path, s.Name)
-				return
+			if pkg.Name != "" && NumImport[pkg.Name] > 1 {
+				return strconv.Quote(pkg.Path)
 			}
-			b.WriteString(s.Pkg.Name)
-			b.WriteByte('.')
-			b.WriteString(s.Name)
-			return
+			return pkg.Name
 
 		case fmtDebug:
-			b.WriteString(s.Pkg.Name)
-			b.WriteByte('.')
-			b.WriteString(s.Name)
-			return
+			return pkg.Name
 
 		case fmtTypeIDName:
 			// dcommontype, typehash
-			b.WriteString(s.Pkg.Name)
-			b.WriteByte('.')
-			b.WriteString(s.Name)
-			return
+			return pkg.Name
 
 		case fmtTypeID:
 			// (methodsym), typesym, weaksym
-			b.WriteString(s.Pkg.Prefix)
-			b.WriteByte('.')
-			b.WriteString(s.Name)
-			return
+			return pkg.Prefix
 		}
 	}
 
-	b.WriteString(s.Name)
+	return ""
 }
 
 // Type